Abstract:
Protective containers for electronic equipment, and methods of testing and manufacture thereof, are provided. The cabinets provide a HEMP protection level to electronic equipment housed therein that meets a HEMP protection level according to

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of, and claims the benefit of priority to, U.S. patent application Ser. No. 11/780,045 filed Jul. 19, 2007, the entire content of which is incorporated herein by reference for all purposes. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Embodiments of the present invention relate to protective containers for electronic equipment, and in particular to enclosure systems and methods for protecting telecommunications equipment from electromagnetic fields. 
         [0003]    A nuclear detonation far above the earth&#39;s surface, for example at 25 miles above sea level, produces an electromagnetic field known as a high altitude electromagnetic pulse (HEMP). Such pulses or energy spikes can cause damage and failure to power systems, telephone networks, electronic devices, and computers across a large geographical area. Systems connected to power lines and telephone wires are particularly vulnerable to the current and voltage surges resulting from an electromagnetic pulse. 
         [0004]    During a HEMP event, damage to telecommunications equipment can be prevented or ameliorated through the use of a protective metallic shielding. For example, telecommunications equipment may be stored in a room having HEMP protected walls. Current approaches for protecting telecommunications racks and enclosures from HEMP exposure are often costly, however, and not well suited for efficient use with standard sized telecommunications storage facilities and components. For example, in some cases custom protected rooms are built to store telecommunications racks. In other cases, vendors lease multiple telecommunications rooms or spaces in which to store oversized hardened enclosures. 
         [0005]    What is needed are improved HEMP protection systems and methods that provide shielding to standard telecommunications rack and device components, while utilizing minimal floor space or meeting other spatial dimension requirements for a telecommunications room or space. Embodiments of the present invention address such needs. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    A telecommunications enclosure encompasses a case or a housing with an interior rack that is dedicated to the telecommunications function and related support facilities. For example, an enclosure can include an integrated telecommunications cabinet and rack. Advantageously, enclosure embodiments of the present invention can be used efficiently and effectively in any of a variety of telecommunications room or space configurations. These enclosures include electrical and fiber entrances which are placed to accommodate a telecommunications environment. 
         [0007]    In a first aspect, embodiments of the present invention provide a method of producing a HEMP protected enclosure for holding an electronic device. The method may include, for example, building a test HEMP protected enclosure according to an enclosure design, performing an acceptance testing procedure on the test HEMP protected enclosure, determining whether the test HEMP protected enclosure meets a HEMP protection level according to MIL STD 188 125 1, and producing a plurality of HEMP protected enclosures according to the enclosure design if the test HEMP protected enclosure meets the HEMP protection level according to MIL STD 188 125 1. In some cases, the test HEMP protected enclosure has a maximum cabinet width dimension that does not exceed about 26 inches and a maximum cabinet depth dimension that does not exceed about 22⅜ inches. In some cases, the test HEMP protected enclosure has a maximum cabinet height dimension that does not exceed about 84 inches. The test HEMP protected enclosure can have a power input point of entry that facilitates entry of a power cable to the interior space from a location external to the cabinet, and a fiber optic cable point of entry that facilitates entry of a fiber optic cable to the interior space from a location external to the cabinet. 
         [0008]    In another aspect, embodiments of the present invention provide a HEMP protected enclosure for holding an electronic device. The enclosure can include, for example, a cabinet having an interior space, and a rack disposed within the interior space. The rack can be configured to support the electronic device. The cabinet can have a maximum width dimension that does not exceed about 26 inches and a maximum depth dimension that does not exceed about 22⅜ inches. The enclosure can provide a HEMP protection level to the telecommunications device that meets a HEMP protection level according to MIL STD 188 125 1. In some cases, the HEMP protected telecommunications enclosure includes a cabinet having a maximum height dimension that does not exceed about 84 inches. In some cases, the enclosure provides a HEMP protection level to the telecommunications device of at least 100 dB attenuation at 1 GHz. In related cases, the enclosure provides a HEMP protection level to the telecommunications device of at least 80 dB attenuation at 1 GHz. The enclosure can further include a power input point of entry that facilitates entry of a power cable to the interior space from a location external to the cabinet, and a fiber optic cable point of entry that facilitates entry of a fiber optic cable to the interior space from a location external to the cabinet. Similarly, the enclosure may include a converter, and a battery coupled with the converter. The enclosure can also include a power filter. A clean output of the power filter can be disposed within the interior space of the cabinet. A dirty input of the power filter can be disposed external to the cabinet. In some cases, the cabinet includes a front opening that is configured to receive the electronic device therethrough. A front opening of the cabinet can have a width dimension of about 23 inches, and a height dimension of about 71 inches. In some aspects, the enclosure includes a power input point of entry that facilitates entry of a power cable to the interior space from a location external to the cabinet, where the power input point of entry is disposed at a top surface of the enclosure. In some aspects, the enclosure includes a fiber optic cable point of entry that facilitates entry of a fiber optic cable to the interior space from a location external to the cabinet, where the fiber optic cable point of entry is disposed at a top surface of the enclosure. The enclosure may also include a power cable coupled with the power input point of entry, and a fiber optic cable coupled with the fiber optic cable point of entry. 
         [0009]    In still another aspect, embodiments of the present invention provide a battery tray for use in a HEMP protected telecommunications enclosure. The battery tray may include a platform configured to support a telecommunications device, and a mounting means coupled with the platform. The mounting means can be disposed above a top surface of the platform. In some cases, the platform has a width dimension that does not exceed about 26 inches, and a depth dimension that does not exceed about 22⅜ inches. 
         [0010]    In yet another aspect, embodiments of the present invention encompass a method of providing HEMP protection to a telecommunications device. The method can include placing the telecommunications device in a HEMP protected telecommunications enclosure. The enclosure can include a cabinet having an interior space, and a rack disposed within the interior space. The rack can be configured to support the telecommunications device. The cabinet can have a maximum width dimension that does not exceed about 26 inches and a maximum depth dimension that does not exceed about 22⅜ inches. The enclosure can provide a HEMP protection level to the telecommunications device that meets a HEMP protection level according to MIL STD 188 125 1. 
         [0011]    In a further aspect, embodiments of the present invention encompass methods of producing a HEMP protected enclosure for holding an electronic device that include building a test HEMP protected enclosure according to an enclosure design, performing an acceptance testing procedure on the test HEMP protected enclosure, determining whether the test HEMP protected enclosure meets a HEMP protection level according to MIL STD 188 125 1, and producing a plurality of HEMP protected enclosures according to the enclosure design if the test HEMP protected enclosure meets the HEMP protection level according to MIL STD 188 125 1, where the test HEMP protected enclosure includes a cabinet width dimension of about 26 inches and a cabinet depth dimension of about 38 inches, a cabinet width dimension of about 65 inches and a cabinet depth dimension of about 30 inches, or a cabinet width dimension of about 26 inches and a cabinet depth dimension of about 20¼ inches. In some cases, the test HEMP protected enclosure includes a cabinet width dimension of about 26 inches and a cabinet depth dimension of about 38 inches. In some cases, the test HEMP protected enclosure includes a cabinet width dimension of about 65 inches and a cabinet depth dimension of about 30 inches. In some cases, the test HEMP protected enclosure includes a cabinet width dimension of about 26 inches and a cabinet depth dimension of about 20¼ inches. In some cases, the test HEMP protected enclosure includes a maximum cabinet height dimension that does not exceed about 84 inches. Optionally, the test HEMP protected enclosure may include a power input point of entry that facilitates entry of a power cable to the interior space from a location external to the cabinet, and a fiber optic cable point of entry that facilitates entry of a fiber optic cable to the interior space from a location external to the cabinet. 
         [0012]    In another aspect, embodiments of the present invention encompass a HEMP protected enclosure for holding an electronic device, where the enclosure includes a cabinet having an interior space, and a rack disposed within the interior space. The rack can be configured to support the electronic device. The test HEMP protected enclosure can include a cabinet width dimension of about 26 inches and a cabinet depth dimension of about 38 inches, a cabinet width dimension of about 65 inches and a cabinet depth dimension of about 30 inches, or a cabinet width dimension of about 26 inches and a cabinet depth dimension of about 20¼ inches. The enclosure can provide a HEMP protection level to the telecommunications device that meets a HEMP protection level according to MIL STD 188 125 1. In some cases, the cabinet includes a maximum height dimension that does not exceed about 84 inches. In some cases, the enclosure provides a HEMP protection level to the telecommunications device of at least 100 dB attenuation at 1 GHz. Optionally, the HEMP protected telecommunications enclosure can include a power input point of entry that facilitates entry of a power cable to the interior space from a location external to the cabinet, and a fiber optic cable point of entry that facilitates entry of a fiber optic cable to the interior space from a location external to the cabinet. In some cases, the HEMP protected telecommunications enclosure can include a converter, and a battery coupled with the converter. Optionally, the HEMP protected telecommunications enclosure may include a power filter. In some instances, a clean output of the power filter can be disposed within the interior space of the cabinet. In some instances, a dirty input of the power filter can be disposed external to the cabinet. According to some embodiments, the cabinet can include a front opening configured to receive the electronic device therethrough. A front opening of the cabinet can have a width dimension of about 23 inches, and a height dimension of about 71 inches. In some cases, the enclosure provides a HEMP protection level to the telecommunications device of at least 80 dB attenuation at 1 GHz. In some cases, an enclosure may include a power input point of entry that facilitates entry of a power cable to the interior space from a location external to the cabinet, where the power input point of entry disposed at a top surface of the enclosure. In some cases, the enclosure may include a fiber optic cable point of entry that facilitates entry of a fiber optic cable to the interior space from a location external to the cabinet, where the fiber optic cable point of entry is disposed at a top surface of the enclosure. Optionally, a HEMP protected telecommunications enclosure can include a power cable coupled with the power input point of entry, and a fiber optic cable coupled with the fiber optic cable point of entry. 
         [0013]    In still a further aspect, embodiments of the present invention encompass methods of providing HEMP protection to a telecommunications device. Exemplary methods include placing the telecommunications device in a HEMP protected telecommunications enclosure, where the enclosure includes a cabinet having an interior space, and a rack disposed within the interior space. The rack can be configured to support the telecommunications device. The cabinet can have a cabinet width dimension of about 26 inches and a cabinet depth dimension of about 38 inches, a cabinet width dimension of about 65 inches and a cabinet depth dimension of about 30 inches, or a cabinet width dimension of about 26 inches and a cabinet depth dimension of about 20¼ inches. In some cases, the enclosure provides a HEMP protection level to the telecommunications device that meets a HEMP protection level according to MIL STD 188 125 1. 
         [0014]    For a fuller understanding of the nature and advantages of the present invention, reference should be had to the ensuing detailed description taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIGS. 1A-D  illustrate various views of a HEMP protected telecommunications enclosure according to embodiments of the present invention. 
           [0016]      FIGS. 2A-F  show various views of a HEMP protected telecommunications enclosure  200  according to embodiments of the present invention. 
           [0017]      FIGS. 3 ,  3 A, and  3 B show transverse views of a HEMP protected telecommunications enclosure according to embodiments of the present invention. 
           [0018]      FIG. 4  shows a top view of an enclosure according to embodiments of the present invention. 
           [0019]      FIG. 5  depicts a top view of an enclosure door according to embodiments of the present invention. 
           [0020]      FIG. 6A  provides a front view and  FIG. 6B  provides a cutaway side view of a HEMP protected telecommunications enclosure according to embodiments of the present 
           [0021]      FIG. 7  provides a schematic of a HEMP protected telecommunications enclosure according to embodiments of the present invention 
           [0022]      FIG. 8  shows a carding arrangement in a HEMP protected telecommunications enclosure according to embodiments of the present invention. 
           [0023]      FIGS. 9A and 9B  illustrate top views of a telecommunications enclosure cabinet according to embodiments of the present invention. 
           [0024]      FIGS. 10A and 10B  depict various views of a HEMP protected telecommunications enclosure according to embodiments of the present invention. 
           [0025]      FIGS. 11 ,  11 A, and  11 B show transverse views of enclosure according to embodiments of the present invention. 
           [0026]      FIGS. 12A-12C  show a battery tray according to embodiments of the present invention. 
           [0027]      FIGS. 13A-13E  illustrate an enclosure system having a sliding cantilever hinge design according to embodiments of the present invention. 
           [0028]      FIG. 14  shows the three measurement ranges of the system for the three Shielding Effectiveness tests. 
           [0029]      FIGS. 15A-15E  show Shielding Effectiveness measurements of a cabinet according to embodiments of the present invention. 
           [0030]      FIG. 16  shows a drive current waveform into a short circuit according to embodiments of the present invention. 
           [0031]      FIG. 17  shows residuals measured on filters for the peak drive currents according to embodiments of the present invention. 
           [0032]      FIGS. 18 and 19  show details of an E2 risetime and entire waveform into a short circuit according to embodiments of the present invention. 
           [0033]      FIG. 20  depicts four recorded E2 residuals according to embodiments of the present invention. 
           [0034]      FIG. 21  shows three measurement ranges of a DTRA system for three Shielding Effectiveness tests according to embodiments of the present invention. 
           [0035]      FIGS. 22A-22E  show Shielding Effectiveness measurements of a cabinet according to embodiments of the present invention. 
           [0036]      FIG. 23  illustrates results of a Shielding Effectiveness measurement according to embodiments of the present invention. 
           [0037]      FIGS. 24 and 25  show residuals measured on filters for the peak drive currents according to embodiments of the present invention. 
           [0038]      FIGS. 26 and 27  show details of an E2 risetime and entire waveform into a short circuit according to embodiments of the present invention. 
           [0039]      FIG. 28  shows recorded E2 residuals according to embodiments of the present invention. 
           [0040]      FIGS. 29A-29C  illustrate various views of a HEMP protected telecommunications enclosure  2900  according to embodiments of the present invention. 
           [0041]      FIGS. 30A-30C  illustrate various views of a HEMP protected telecommunications enclosure  3000  according to embodiments of the present invention. 
           [0042]      FIGS. 31A-31C  illustrate various views of a HEMP protected telecommunications enclosure  3100  according to embodiments of the present invention. 
           [0043]      FIG. 32  shows an exemplary Anderson plug assembly  3200  coupled with a cabinet mounting rail assembly  3210  according to embodiments of the present invention. 
           [0044]      FIG. 33  shows a spool assembly  3300  according to embodiments of the present invention. 
           [0045]      FIG. 34  shows a hinge assembly  3400  of an enclosure according to embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0046]    Embodiments of the present invention can enhance the survivability of a telecommunications system or device against an HEMP event, while at the same time providing optimum space utilization of a telecommunications space or room. Telecommunication enclosures meet established standards for HEMP protection, and dimensional specifications for telecommunications infrastructure administration, pathways, spaces, and the like. Enclosures can be pre-wired or pre-packaged for cost-effective shipment and installation. Embodiments provide off-the-shelf solutions and can eliminate the need for customized designs. In some cases, enclosures can provide customized dimensions or components. For example, an enclosure can be customized pursuant to an equipment configuration to provide desired size dimensions and power needs. In some cases, an enclosure may include a custom battery tray. 
         [0047]    Turning now to the drawings,  FIGS. 1A-D  illustrate various views of a HEMP protected telecommunications enclosure  100  according to embodiments of the present invention. Telecommunications enclosure  100  includes a cabinet  110  having a top  120 , a bottom  130 , a front  140 , a back  150 , and two sides  160 . Cabinet  110  defines an interior space  170 , and is coupled with a door  180  via a hinge assembly  182 . When door  180  is closed, it can be securely fastened to cabinet  110  with latches  184 . Typically, door  180  is wide enough to accommodate installation and routine maintenance of equipment housed in cabinet  110 , and robust enough to provide adequate shielding. Enclosure  100  also includes an air exhaust system  122  disposed toward top  120  of cabinet  110 . Exhaust system  122  may include, for example, two 48 volt fans located at or toward cabinet top  120  and accessible for maintenance and repair. In some cases, exhaust system  122  vents out the top of the cabinet. In some cases, exhaust system  122  vents out the back of the cabinet. In a preferred embodiment, exhaust system  122  vents out the back of the cabinet, toward the top. Enclosure  100  includes rack components such as vertical mounting rails or tapped mounting angles  162  and chassis supports  164  coupled with cabinet sides  160 . Enclosure  100  also includes an air intake system  152 , a power filter system  154 , a fiber optic cable point of entry (POE)  124 , and a power input point of entry (POE)  126 , each coupled with back  150  of cabinet  110 . In some embodiments, interior cables from filter system  154  are clean ( FIG. 1C ), and exterior cables from filter system  154  are dirty ( FIG. 1D ). 
         [0048]    Telecommunications enclosure  100  also includes a base mounting support  190  having a front flange  192  and a rear flange  194 , where each flange extends the widths of cabinet  110 . Often, flanges  192 ,  194  will include means for attachment with a floor or supporting surface. For example, flanges  192 ,  194  may include apertures for attachment with the floor via floor anchoring bolts. The apertures may be elongated to provide easy installation or to accommodate for less exact installation. In some embodiments, flanges  192 ,  194  are configured to be as narrow as possible while still accommodating installation via the anchoring bolts or other means of attachment. Telecommunications enclosure  100  may also include a top support  128 , which in some cases may include an auxiliary bar welded to the top of cabinet  110 . The auxiliary bar can be aligned parallel with the front and back of cabinet  110 . In a preferred embodiment, the bar or top support includes three holes, three inches apart, tapped for a ⅝″ threaded rod. The top support may be configured to accommodate components mounted on or toward the top of the cabinet, for example a power line filter, a fiber point of entry, and the like. In some embodiments, base mounting support  190  or top mounting support  128 , or the combination thereof, can be configured to meet Zone 4 stress requirements. 
         [0049]    Enclosure  100  or component parts thereof are typically configured to certain specifications or dimensions. For example, the enclosure can be configured for installation in a standard telecommunications room or space, such that the dimensions of the enclosure do not exceed certain limits. In some cases, enclosure  100  can be manufactured not to exceed a volume or space of about 26″ width by about 22⅜″ depth by about 84″ height. This may include the frame or relay rack size, including panel covers. The enclosure can include two vertical mounting rails on each side, and the forward rails can be located approximately 8 inches into the cabinet as measured from the cabinet front. This particular configuration is useful for enclosures that hold telecommunications equipment. Enclosures that hold computer servers may provide a different mounting rail configuration. The rails can be manufactured from 12 Gauge steel, and can include holes which may be tapped according to an American National Standard. For example, in some embodiments, the rails are tapped with 12-24 National Coarse (NC) holes along their entire length or one or more portions thereof. The holes may be punched so that they are aligned in a straight vertical line, which can allow for ease of telecommunications equipment installation. In some cases, enclosure elements such as the vertical mounting rails are configured to meet or exceed seismic standards. For example, the rails can be manufactured to meet a Zone 4 seismic specification. Typically a cabinet includes four vertical mounting rails. Embodiments of the present invention include enclosures and component elements thereof that are constructed according to certain procedures or standard specifications such as MIL-HDBK-423. In some embodiments, enclosure  100  is configured for placement in a but or prefabricated building located along a telecommunications backbone, at least part of which may be near a railroad grid or right-of-way. 
         [0050]    Enclosure  100  can define an electromagnetic barrier, so as to prevent or limit HEMP fields and conducted transients from entering the enclosed space. In some cases, enclosure  100  complies with minimum requirements or design objects as set forth in certain standards, such as MIL-STD-188-125-1 (including Appendices), which is a standard for high-altitude electromagnetic pulse (HEMP) protection for ground-based facilities performing critical, time-urgent missions. For example, embodiments of the present invention encompass enclosures and component parts that provide at least about 80 dB attenuation at 1 GHz. In some embodiments, enclosures and component parts provide at least about 100 dB attenuation at 1 GHz. Enclosure  100  and components thereof can also comply with safety, spatial and environmental design guidelines applied to telecommunications equipment, such as NEBS™. Similarly, enclosure  100  and components thereof can comply with documents such as Telcordia Technologies GR-63-CORE and GR-1089-CORE, as well as related standards required by or developed by organizations such as FCC, CISPR, IEC, IEEE, ASTM, ANSI, and ETSI. The fiber optic cable point of entry can include a shielded wave guide, and in some cases is located on the top of the enclosure, toward the front, so as to allow for ease of internal cable management. In some cases, an air intake system includes a shielded passive vent, which may be constructed of machined, steel honeycomb. The vent can be circumferentially welded to a mounting surface or cabinet surface according to a procedure or standard specification such as MIL-HDBK-423. 
         [0051]      FIGS. 2A-F  show various views of a HEMP protected telecommunications enclosure  200  according to embodiments of the present invention. Telecommunications enclosure  200  includes a cabinet  210  having a top  220 , a bottom  230 , a front  240 , a back  250 , and two sides  260 . In some embodiments, cabinet  210  has or does not exceed a total height H of 81 inches, a total width W of 26 inches, and a total depth D of 20 inches. In a preferred embodiment, total height H is 84 inches. Depth D may represent the distance from the exterior front surface of door  280  to the back surface of cabinet back  250 , and in some cases does not include front flange  292 , rear flange  294 , or air intake system  252 . Enclosure  200  may also include a top support or structural angle  228  that can be adjusted or moved to any desired position between front  240  and back  250 . Top support  228  can be coupled with one or more auxiliary bars  229 . Cabinet  210  includes struts  212  along which auxiliary bars  229  may slide or move, thus allowing top support  228  to be adjustably positioned to any location between cabinet front  240  and cabinet back  250 , as indicated by arrow  228 ′. Auxiliary bars  229  are coupled with struts  212  via spring nuts  214 . In a preferred embodiment, the enclosure does not include an adjustable top support and auxiliary bars, struts, and spring nuts. 
         [0052]    In some cases, enclosure  200  includes one or more fire wall shelves  268 . These shelves can be perforated for air flow, and can be adjusted or moved to any desired position between top  220  and bottom  230 . Typically, a fire wall shelf  268  is installed above a piece of telecommunications equipment. In a preferred embodiment, the enclosure does not include a fire wall shelf. Cabinet  210  defines an interior space  270 , and is coupled with a door  280  via a hinge assembly  282 . Enclosure  200  also includes an air exhaust system  222 , a fiber optic cable point of entry  224 , and a DC power input point of entry  226 , each disposed toward top  220  of cabinet  210 . Fiber optic cable POE  224  can include a wave guide with an EMI/RFI gasket. Air exhaust system  222  can provide, for example, an air flow rate of 450 cubic feet per minute (CFM). For example, the system can include two DC fans providing 225 CFM each. In some embodiments, the system includes two P1751 DC fans, available from Pelonis Technologies, Inc. (Malvern, Pa.). Enclosure  200  includes vertical mounting rails  262  and chassis supports  264  coupled with cabinet sides  260 . Chassis supports  264  can be adjustable to any desired position between top  220  and bottom  230 , and can provide support for chassis shelves  266 . In a preferred embodiment, the chassis supports are fixed, and not adjustable. Depending on how much equipment is placed inside the enclosure, any number of fixed or sliding fire wall shelves  268  or chassis shelves  266  may be needed or desired. In some cases, one or more of these shelves can be configured to comply with safety, spatial and environmental design guidelines applied to telecommunications equipment, such as NEBS™ 
         [0053]    Enclosure  200  also includes an air intake system  252  coupled with back  250  of cabinet  210 , and a power filter system  254  disposed near cabinet top  220 . In some embodiments, power filter system  254  includes a power vault with one or more DC-line filters, and converts a dirty electrical input to a clean electrical output that is transmitted to a load. Power filter system  254  may be mounted on the interior of cabinet  210 . In a preferred embodiment, the power filter system is mounted on the exterior of cabinet  210 . Enclosure  200  can be installed according to standard installation techniques without incurring damage to power filter system  254 . Air intake system  252  can include a removable and washable outside dust filter  252   a  and an inside one inch thick steel electromagnetic interference (EMI) and radiofrequency interference (RFI) honeycomb filter  252   b . In a preferred embodiment, the air intake system does not include a dust filter. An enclosure can include durable hinges, latches, and handles that will not buckle, misalign, or degrade over an approximately 20 year lifespan. The front of the enclosure will typically define a large enough opening to allow for ease of equipment installation and maintenance. For example, the size of the opening can be maximized to allow for removal of installed telecommunications components such as cards. 
         [0054]      FIGS. 3 ,  3 A, and  3 B show transverse views of enclosure  300  according to embodiments of the present invention.  FIG. 3  corresponds to Section A-A as depicted in  FIG. 2A . Telecommunications enclosure  300  includes a cabinet  310  having a front  340 , a back  350 , and two sides  360 . Cabinet  310  defines an interior space  370 , and is coupled with a door  380  via a hinge assembly  382 . In some embodiments, hinge assembly  382  includes a piano hinge. In a preferred embodiment, the hinge assembly does not include a piano hinge. Enclosure  300  includes vertical mounting rails  362  and chassis supports  364  coupled with cabinet sides  360 . Enclosure  300  also includes an air intake system  352  coupled with back  350  of cabinet  310  interior. Door  380  can be sealed with cabinet front  340  with a gasket  384  that extends around a door opening rim  386 . In some embodiments, gasket  384  includes a knife edge/copper finger stock gasketing. Enclosure gaskets such as gasket  384  can provide an air seal, an RFI seal, or any other suitable seal, for example as specified in MIL-STD-188-125-1. In a preferred embodiment, the door is not sealed with the cabinet front with a gasket that extends around a door opening rim. Cabinet  310  can have a depth D that extends from cabinet front  340  to cabinet back  350 , where depth D is or does not exceed 20 inches. A distance between the left door opening rim  386  ( FIG. 3A ) and the right door opening rim  386  ( FIG. 3B ), which may also be referred to as a clear opening, can be within a range from about 19 inches to about 22 inches. In some embodiments, this width dimension is about 20.5 inches. In a preferred embodiment, this width dimension is about 23.5 inches. What is more, this width dimension can be modified when the enclosure is configured as a double-wide design. The width dimension can be configured so as to facilitate telecommunications equipment installation and maintenance activities. In some cases, the depth of rim  386  is about 1.125 inches. In some cases, the thickness of gasket  384  is about 0.250 inches. As noted above, in a preferred embodiment the door is not sealed with the cabinet front with a gasket that extends around a door opening rim. 
         [0055]    A top view of an enclosure  400  is shown in  FIG. 4 , according to embodiments of the present invention. Telecommunications enclosure  400  includes a cabinet  410  having a top  420 , a front  440 , a back  450 , and two sides  460 . Enclosure  400  also includes a top support  428  coupled with two auxiliary bars  429 . Cabinet  410  includes two struts  412  along which auxiliary bars  429  may slide or move, thus allowing top support  428  to be adjustably positioned to any location between cabinet front  440  and cabinet back  450 , as indicated by arrows  428 ′. Auxiliary bars  429  are coupled with struts  412  via spring nuts  414 . In a preferred embodiment, the top support is fixed, and not adjustable. 
         [0056]    Cabinet  410  is coupled with a door  480  via a hinge assembly (not shown). Enclosure  400  also includes an air exhaust system  422 , a fiber optic cable point of entry  424  and a power input point of entry  426  disposed toward top  420  of cabinet  410 . In some embodiments, fiber optic cable POE and power input POE  426  are configured with grommets. In a preferred embodiment, the enclosure does not include a fiber optic cable POE and power input POE configured with grommets.  FIG. 5  shows a top view of a door  580  according to embodiments of the present invention. Door  580  is coupled with a hinge assembly  582  for attachment with an enclosure cabinet, a gasket  584 , a gasket guide  586 , and a hat section stiffener  588 . Gasket  584  and gasket guide  586  extend around the perimeter of door  580  to provide a seal between door  580  and the front of the cabinet. In a preferred embodiment, the enclosure does not include a gasket and gasket guide extending around the perimeter of the door. 
         [0057]      FIG. 6A  provides a front view and  FIG. 6B  provides a cutaway side view of a HEMP protected telecommunications enclosure  600  according to embodiments of the present invention. Telecommunications enclosure  600  includes a cabinet  610  having a top  620 , a bottom  630 , a front  640 , a back  650 , and two sides  660 . Cabinet  610  is coupled with a door  680 , and includes a fiber optic cable point of entry  624 . Enclosure  600  includes vertical mounting rails  662  coupled with cabinet sides  660 . Cabinet  610  includes an exterior room  612  configured to house a power filter system  654 , and an interior room  614  configured to house an air exhaust system  622 . In some embodiments, power filter system  654  includes a power vault with one or more DC-line filters, and converts a dirty electrical input (located exterior to the enclosure) to a clean electrical output (located within the enclosure) that is transmitted to a load. Cabinet  610  defines an interior space  670 , which can house any of a variety of telecommunications components, including a Ciena transport equipment module  670   a , a dispersion compensation module (DCM)  670   b , a Ciena transport equipment module  670   c , a DC converter  670   d , and a battery string  670   e . In a preferred embodiment, the enclosure includes two battery strings. In some embodiments, an enclosure does not include a transport equipment module. Two battery strings  670   e  can provide stand-along self-sufficiency to enclosure  600  during a power outage. For example, a first string can provide power to the load, and the second string can provide N+1 protection, where N is the number of battery strings required to satisfy the backup time requirement based on the current load. The +1 is (1) additional string as a redundancy precaution. In a preferred embodiment, (1) string is needed to satisfy the total back-up power requirements for a minimum of 8 hours plus (1) string for redundancy. Enclosure  600  also includes an air intake system  652  coupled with back  650  of cabinet  610 . In some embodiments, telecommunications equipment is installed in an enclosure starting at the bottom, and proceeding toward the top, so as to leave as much empty space toward the top as possible. 
         [0058]    Enclosure  600  is typically configured for installation in a standard telecommunications room or space, such that the dimensions of the enclosure do not exceed certain limits. For example, enclosure  600  can be manufactured not to exceed dimensions of about 26″ in width, about 22⅜″ in depth, and about 84″ in height, including any exterior mounted power line filters, but exclusive of any door handles, hinges, air intake vents, or bottom or top bracing. 
         [0059]    Enclosure  600  can also be constructed so as to accommodate or support telecommunications equipment having certain parameters. For example, enclosure  600  can be constructed to accommodate two battery strings, each weighing about 282.4 pounds, and a DC-DC converter weighing about 30 pounds. In some cases, enclosure  600  can be constructed to support and house telecommunications equipment having a combined weight of about 333 pounds. In some cases, this combined weight may be in a range from about 200 pounds to about 500 pounds. In some embodiments, the cabinet occupies a minimal amount of space, while still being able to accommodate installation of telecommunications equipment and routine maintenance of fans and filters. In some embodiments, the enclosure contains other electronic equipment in addition to or instead of telecommunications equipment. 
         [0060]      FIG. 7  provides a schematic of a HEMP protected telecommunications enclosure  700  according to one embodiment of the present invention, and illustrates how power can be brought from an external site into the interior of enclosure  700 . Telecommunications enclosure  700  includes a cabinet  710  having a top  720 , a bottom  730 , and two sides  760 . Cabinet  710  includes a power filter system  754 , a DC converter  770   d , an air exhaust system  722 , a breaker panel  770   f , a Cicna transport equipment module  770   c , and two battery strings  770   e . In some embodiments, the enclosure does not include a transport equipment module. In some embodiments, during operation site power can be supplied to the cabinet from site batteries  700   a  or commercial AC  700   b . Where the power source is commercial AC  700   b , power is transmitted through site rectifiers  700   c . Power is then transmitted through a buss  700   d , such as a −48v site DC buss, optionally through a site battery distribution feeder bay  700   e , and through a butt splice or H-tap  700   f . In some embodiments, 60 amp breakers may be required or desired at the BDFB to insure that the recharge current for the cabinet batteries does not trip the BDFB breakers. Breaker panel  770   f , which is attached with fans  722  and transport equipment  770   c , acts as a load. Similarly, batteries  770   e  act as a load. When site power is lost, or when site voltage drops below a threshold, site power can be disconnected at a custom DC converter  770   d , and cabinet batteries  770   e  will carry the load for the cabinet. When site power is restored, for example via commercial AC or a generator, custom DC converter  770   d  can switch back to normal operation and the cabinet can be powered via site power. The A and B side of filter system  754  can provide redundancy to filter. For example, if the A side is compromised, the B side can accommodate the needs of the enclosure system. In some embodiments, an estimated maximum load includes 2 amps for fans and 11.6 amps for transport equipment. 
         [0061]    In some embodiments, custom DC converter  770   d  may include, for example, a −48 VDC to −48 VDC converter, for example a Valere −48v to −48v converter, shelf part #HK25S-ANN-VT, converter module part #DCHF1000AA-VV26. During normal operation, site power can be supplied to the cabinet. Breaker panel  770   f , which may be coupled with fans  722  and transport equipment  770   c , and cabinet batteries  770   e  may act as loads. When the DC input voltage drops below a low operating threshold of the converter input, which may occur due site battery drain after an extended DC power outage, the converter can stop converting site DC and cabinet batteries  770   e  can carry the load for only the cabinet. When site power is restored, for example via commercial AC or a generator, or the converter input voltage rises above the input threshold, the converter can resume converting site DC and the cabinet can be powered and the cabinet batteries can be charged via the site power. In a preferred embodiment, the enclosure is configured so that if the site loses power, the cabinet batteries pick up only the cabinet load and not the rest of the site. This can be accomplished by the DC converter. When site power is lost or drops below an input voltage threshold the converter shuts off and isolates the site from the cabinet batteries. Thus, the cabinet is powered by the batteries. The converter turns back on when the site power is restored. In some cases the input voltage threshold is relatively low, and a switch from external to internal power can be delayed. This time delay can be a function of the existing load at a site and the Amp Hour (AH) capacity of the site battery plant. A longer delay can correspond to a larger site battery plant AH and a smaller site load. Conversely, a shorter delay can correspond to a smaller site battery plant AH and a larger site load. The time delay can enable the equipment to run off site back up longer thus extending the overall run time of the equipment. In a preferred embodiment, the enclosure is configured to use site power first. In some embodiments, individual sites may have different battery requirements. 
         [0062]    The power filter system can include one or more DC HEMP shielded power line filters, such as a 30 amp power filter. Power filters encompass electronic circuits that locate and eliminate surges, harmonic transient currents, spikes, and other unwanted signals in telecommunications equipment. The filters are mounted external to the cabinet, for example on the cabinet top, and can include a dirty input to accommodate an A/B feed coming from the site. In some embodiments, the power filters are installed in accordance with a procedure or standard specification such as MIL-HDBK-423. 
         [0063]    The power filter system can also include or be adapted to couple with an external DC power connection. For example, the dirty power input can be configured to receive a wide variety of power cables, such as a #6 power cable (e.g. 6 AWG, XHHW, black, copper, stranded, 10 conductor, 600 volt). In some embodiments, the telecommunications enclosure includes a length of cable extending from the filter, which may be slack and coiled. Cables passing through the enclosure cabinet can be configured in accordance with a procedure or standard specification such as MIL-HDBK-423. In some embodiments, a filter output (e.g. clean) that runs inside of the cabinet is pre-wired with a five foot length of #10 power cable. Various components of the telecommunications enclosure, for example elements for power entry into and exit out of a power filter, may be pre-installed. Enclosures may therefore be well suited for convenient installation. For the exterior of the enclosure, on-site installation power work may include butt splicing site power cables to a #6 cable that protrudes from the enclosure or filter. For the interior of the enclosure, on-site installation power work may include terminating a #10 power cable to a DC converter, which can feed power to a distribution panel for other components in the enclosure. Power filter system  754  can include internal and external DC cables connected to one or more DC filters. In some cases, these cables can be pre-connected to the filters prior to shipment of the cabinet, to protect the integrity of the DC filters during cabinet installation. In a preferred embodiment, DC filters are configured to meet RF and electromagnetic filtering and size requirements or limitations of a customer (e.g. MIL or NEBS™ standards). Such requirements or limitations may encompass standards set forth by a utility or telecommunications company. In some embodiments, a #6 AWG (American Wire Gauge wire size) can be used for a DC filter input (external power) and a #10 AWG can be used for a DC filter output (internal to a cabinet bay). Cabinets having pre-connected cables can reduce the amount of onsite power installation work to standard terminations performed by technicians. 
         [0064]    Battery string  770   e  can be configured to sit on two custom made trays, one disposed above the other, at or toward the bottom of the cabinet. In some cases, the batteries have dimensions of 15.59″ length, 16.96″ width, and 10.04″ height. Trays upon which batteries sit may add 1″ height and/or 1′ width to the space occupied by the batteries. Any of a variety of batteries can be used in the cabinet, as long as they physically fit inside of the enclosure. For example, a string of Northstar NSB 90 FT batteries can be used to provide 10.8 amps for 8 hours. String dimensions are 15.59″ in length, 16.96″ in width, and 10.04″ in height, and string weight is 282.4 lbs. In some embodiments, cabinet batteries are sized and selected to provide an optimal or desired back-up capacity while still fitting inside the cabinet. Back-up times can be estimated by, for example, calculating worst-case power loads for various transport configurations and comparing to usable batteries. Exemplary estimations are shown in Table 1, where back-up times exceeded a requirement of 8 hours. These estimations include maximum power draws for each equipment configuration. GNB Marathon M12V90FT and NorthStar NSB-90-FT batteries are compared. 
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Max Draw (in amps) 
                 Marathon M12V90FT 
                 NorthStar NSB.90.FT 
                 Time on Battery 
                 Time on Battery 
               
               
                   
                 includes 1.5 amps 
                 @8 Hours 
                 @8 Hours 
                 w/2 strings 
                 w/2 strings 
               
               
                 @ 6 wavelengths 
                 for fans 
                 (in amps) 
                 (in amps) 
                 (in hours) Marathon 
                 (in hours) NorthStar 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Amp 
                 3.6 
                 10.1 
                   
                 45.6 
                 48.8 
               
               
                 Amp (w/1 
                 5.4 
                 10.1 
                   
                 30.3 
                 32.4 
               
               
                 Raman) 
               
               
                 Amp (w/2 
                 6.3 
                 10.1 
                   
                 25.9 
                 27.7 
               
               
                 Raman) 
               
               
                 Regen 
                 11.6 
                 10.1 
                 10.8 
                 14.0 
                 15.0 
               
               
                 Regen (w/ 
                 13.1 
                 10.1 
                 10.8 
                 12.4 
                 13.3 
               
               
                 Raman) 
               
               
                 Terminal 
                 11.6 
                 10.1 
                 10.8 
                 14.0 
                 15.0 
               
               
                 Terminal (w/ 
                 13.1 
                 10.1 
                 10.8 
                 12.4 
                 13.3 
               
               
                 Raman) 
               
               
                 Core Director CI 
                 44.7 
                   
                 10.8 
               
               
                   
               
             
          
         
       
     
         [0065]    In some embodiments, a cabinet can be configured with two strings of NorthStar NSB-90-FT batteries, having dimensions of 10.04″ height, 4.24″ width, and 15.59″ length, at 70.6 lbs per cell and 282.4 lbs per string (4 cells per string). Each string can provide 10.8 amps during an 8 hour discharge, where two strings are equivalent to 21.6 amps per cabinet. In some embodiments, an enclosure can include two strings of EnerSys SBS C11 batteries, providing 11.3 Amps over 8 hours, or 20 Amps over 4 hours. At 6 wavelengths, the EnerSys SBS C11 configuration also provides the following values for reserve time: Amp 51.1, Amp (w/1 Raman) 33.9, Amp (w/2 Raman) 29.0, Regen 15.7, Regen (w/Raman) 13.9, Terminal 15.7, and Terminal (w/Raman) 13.9. The battery length is 15.6″, the width is 4.1″ per cell or 16.4″ per string, and the depth is 10.4″. The weight is 246.4 lbs per string. 
         [0066]      FIG. 8  shows a carding arrangement in a HEMP protected telecommunications enclosure  800  according to one embodiment of the present invention. A telecommunications rack chassis, for example a Ciena® chassis, will typically include a number of slots configured for receiving enclosure elements such as subscriber cards, line cards, switch fabric modules, and the like. This figure illustrates an exemplary arrangement of cards in a telecommunications enclosure, where the card placement spans from one side to the other. Enclosure embodiments of the present invention provide sufficient room to access and remove the cards through the cabinet door, post-installation, for ongoing maintenance purposes. Components of an enclosure such as a Regen Terminal may include, for example, a power distribution unit (PDU)  810 , a common dispersion compensation module (DCM)  815 , a fan  820 , an SCM/enhanced BE module (EBEM)  825 , anNCP2  830 , a wreal signal to electrical signal (W2E) (ILA-2)  835 , an electrical signal to wreal signal (E2W) integrated line amplifier (ILA-2)  840 , a router  845 , a multiplexer/demultiplexer (MUX/DEMUX)  850 , a transceiver (XCVR) or muxceiver (MUXCVR)  855 , a (PS)/power distribution unit (PDU)  860 , a filler panel  865 , and the like. 
         [0067]      FIG. 9A  illustrates a top view of a telecommunications enclosure cabinet  900  according to embodiments of the present invention. The external depth is represented by A, the distance between the mounting holes of mounting rails is represented by B, and the usable area space is represented by C. In some embodiments, a telecommunications enclosure has an external depth A of about 22.3 inches. In a preferred embodiment, external depth A does not exceed about 22.3 inches. In some embodiments, a telecommunications enclosure has a distance between the mounting holes of mounting rails B of 22¼ inches. In some cases, distance between the mounting holes of mounting rails B can be in a range from between about 18¼ and about 22¼ inches. In some cases, distance between the mounting holes of mounting rails B does not exceed 22¼ inches. 
         [0068]      FIG. 9B  illustrates a top view of a telecommunications enclosure cabinet  900  according to embodiments of the present invention. The internal usable height is represented by D, the external height is represented by E, the chassis clearance is represented by F, the internal usable width is represented by G, and the external width is represented by H. In some embodiments, a telecommunications enclosure has an external height E of about 84 inches. In a preferred embodiment, external height E does not exceed 84 inches. In a preferred embodiment, a telecommunications enclosure has an external width H of about 26 inches. In a preferred embodiment, external width H does not exceed about 26 inches. 
         [0069]      FIGS. 10A and 10B  show various views of a HEMP protected telecommunications enclosure  1000  according to embodiments of the present invention. Telecommunications enclosure  1000  includes a cabinet  1010  having a top  1020 , a bottom  1030 , a front  1040 , a back  1050 , and two sides  1060 . In some embodiments, cabinet  1010  has or does not exceed a total height H of about 84 inches, a total width W of about 26 inches, and a total depth D of about 20 inches. Depth D may represent the distance from the front surface of door  1080  to the back surface of cabinet back  1050 , and in some cases does not include front flange  1092 , rear flange  1094 , or air intake system  1052 . Enclosure  1000  may also include a top support or structural angle that can be adjusted or moved to any desired position between front  1040  and back  1050 . In a preferred embodiment, the top support is fixed, and not adjustable. 
         [0070]    Enclosure  1000  also includes an air exhaust system  1022 , one or more fiber optic cable and/or power input points of entry  1024 , each disposed toward top  1020  of cabinet  1010 . In a preferred embodiment, POE  1024  includes a metal tube. Air exhaust system  1022  can provide, for example, an air flow rate of 450 cubic feet per minute (CFM). For example, the system can include two DC fans providing 225 CFM each. In some embodiments, the system includes two P1751 DC fans, available from Pelonis Technologies, Inc. (Malvern, Pa.). In a preferred embodiment, as shown here, exhaust system  1022  can be disposed on a side of the enclosure  1000 , for example the back side  1050 . 
         [0071]      FIGS. 11 ,  11 A, and  11 B show transverse views of enclosure  1100  according to embodiments of the present invention. Telecommunications enclosure  1100  includes a cabinet  1110  having a front  1140 , a back  1150 , and two sides  1160 . Cabinet  1110  defines an interior space  1170 , and is coupled with a door  1180  via a hinge assembly  1182 . In some embodiments, hinge assembly  1182  includes a hinge. In a preferred embodiment, the hinge assembly includes a sliding cantilever hinge. Such an assembly provides a sliding cantilever on which to place a pivot point, allowing for a desired articulation. Enclosure  1100  includes vertical mounting rails  1162  and chassis supports  1164  coupled with cabinet sides  1160 . Door  1180  can be sealed with cabinet front  1140  with a gasket  1184  that extends around a door opening rim  1186 . In some embodiments, gasket  1184  includes a knife edge/copper finger stock gasketing. Relatedly, gasket  1184  can include a double finger stock gasket. Enclosure gaskets such as gasket  1184  can provide an air seal, an RFI seal, or any other suitable seal, for example as specified in MIL-STD-188-125-1. Cabinet  1110  has a depth D that extends from cabinet front  1140  to cabinet back  1150 , where depth D is or does not exceed about 20 inches. A distance between the left door opening rim  1186  ( FIG. 11A ) and the right door opening rim  1186  ( FIG. 11B ) may be in a range of about 19 inches to about 22 inches. A depth of rim  1186  can be about 1.125 inches. In a preferred embodiment, the enclosure does not include a gasket having a knife edge/copper finger stock gasket or a double finger stock gasket. 
         [0072]      FIGS. 12A-12C  show a battery tray  1200  according to one embodiment of the present invention. As illustrated in top view  FIG. 12A , tray  1200  includes a platform  1210  and two mounts  1212 . Platform width A is about 20⅞ inches. Platform depth B is about 15½ inches. Distance C between platform front  1210   a  and mount  1212  is about 6⅛ inches. Mounts  1212  are configured to couple with mounting rails in an enclosure. Front view  FIG. 12B  similarly illustrates platform  1210  and mounts  1212  of tray  1200 . Mounts  1212  include mount holes  1213  having a radius of about 3/16 inch. Mount width D is about 23⅞ inches. Mounting hole width E is about 22¼ inches. Tray height F is about 9 inches. Mount width G is about 1⅝ inches. Mount hole spacing distance H is about 1¾ inches. Distance I between platform bottom  1210   b  and lower mount hole  1213   a  is about 1 inch. As shown in side view  FIG. 12C , tray  1200  includes platform  1210 , mount  1212 , and front side panel  1220 . Front side panel leading edge height  1220   a  is about 1½ inches. Platform height K is about 1½ inches. Front side panel depth L is about 6⅛ inches. Battery tray  1200  can provide advantages over some known trays that mount from the cabinet bottom, or that may not otherwise easily fit or mount into the enclosure. 
         [0073]      FIGS. 13A-13E  illustrate an enclosure system  1300  having a sliding cantilever hinge design according to embodiments of the present invention. As shown in the front isometric view provided by  FIG. 13A , enclosure system  1300  includes a seismic brace  1310 , a rack channel and spacer assembly  1320 , a door  1330 , a plurality of door clamps  1332 , a plurality of power filters  1340 , and a cantilever hinge assembly  1350 . Cantilever hinge assembly  1350  includes a pin guide  1352  coupled with the body  1305  of the enclosure, and a pin  1354  coupled with the door  1330 . As shown in the rear isometric view provided by  FIG. 13B , enclosure system  1300  includes a seismic brace  1310 , a door  1330 , a plurality of door clamps  1332 , a plurality of power filters  1340 , a cantilever hinge assembly  1350 , an intake vent  1360 , and an exhaust vent  1362 . Each cantilever hinge assembly  1350  includes a pin guide  1352  coupled with the body  1305  of the enclosure, and a pin  1354  coupled with the door  1330 .  FIG. 13C  provides a partial side view (door open) of the enclosure system  1300 . As seen here, the cantilever hinge assembly  1350  includes a pin guide  1352  coupled with the body  1305  of the enclosure, and a pin  1354  coupled with the door  1330 .  FIG. 13D  provides a top view (door open) of the enclosure system  1300 . As seen here, the cantilever hinge assembly  1350  includes a pin guide  1352  coupled with the body  1305  of the enclosure, and a pin  1354  coupled with the door  1330 . Pin guide  1352  includes a pin guide aperture  1356  that is adapted to receive pin  1354 . In use, pin  1354  is disposed within pin guide aperture  1356 , and can slide or translate laterally within the aperture.  FIG. 13E  provides a top view (door closed) of the enclosure system  1300 . As seen here, the cantilever hinge assembly  1350  includes a pin guide  1352  coupled with the body  1305  of the enclosure, and a pin  1354  coupled with the door  1330 . Pin guide  1352  includes a pin guide aperture  1356  that is adapted to receive pin  1354 . In use, pin  1354  is disposed within pin guide aperture  1356 , and can slide or translate laterally within the aperture. 
         [0074]    Enclosures according to embodiment of the present invention may include various accessories or features, including input and outputs such as cables and power cords, cutouts for connectors, LEDs, displays, ventilating slots, holes, or louvers in the top, back, or sides or provisions for mounting exhaust fans or blowers. Enclosures may also include wire management accessories such as cable management panels, clips, and cableway covers. Typically, the enclosure is hardened and is designed to shield from electromagnetic or radiofrequency interference. For example, the enclosure cabinet can be constructed of steel, which exhibits desirable shielding properties. Depending on the power level involved, points of entry into the enclosure can be protected from electromagnetic pulse by using specially-designed surge protectors. 
         [0075]    Various testing protocols can be used to determine performance characteristics of an enclosure. For example, one testing protocol involves four suites of tests, including a heat testing dummy load suite, a heat testing functional equipment suite, a power system verification test suite, and an NEBS™ testing (empty cabinet only including fans and passive power filters) suite. A heat testing (dummy load equipment configuration) suite can determine whether a cabinet provides adequate or desired ventilation and temperature control characteristics in typical and borderline operating environments. An exemplary test involves simulating the heat production and power draw of a 60 amp system. Normal operating environment conditions can be tested within various locations of the cabinet (e.g. top, middle, and bottom). The test can determine whether the temperature stays within acceptable operating levels, and identify and measure any difference between the ambient temperature outside the cabinet and the internal cabinet temperature. Fan failures can be tested to identify and measure any effect on the internal temperature and the length of time it takes to reach steady state relative to the ambient temperature outside the cabinet. Such tests can involve disabling one or both of the cabinet fans, or the chassis fan. Airflow obstruction of external air intake vents can be tested, to determine any effect an obstruction (e.g. 50%) would have on the internal cabinet temperature over time. HVAC system failures can be tested inside a thermal chamber to determine any insulating properties the cabinet provides under a range of typical to extreme conditions that would impact the relative difference between external and internal temperature. 
         [0076]    A heat testing (15 amp functional equipment configuration) suite can involve a specific equipment configuration that draws approximately 15 amps that is installed inside the cabinet. This suite can determine whether the cabinet provides adequate ventilation and temperature control in typical, borderline, and extreme operating environments when fully loaded with functioning equipment such as telecommunications equipment. This suite can also determine how the installed equipment performs in typical, borderline, and extreme operating environments. The test can determine whether the temperature stays within acceptable operating levels, and identify and measure any difference between the ambient temperature outside the cabinet and the internal cabinet temperature. Fan failures can be tested to identify and measure any effect on the internal temperature and the length of time it takes to reach steady state relative to the ambient temperature outside the cabinet. Such tests can involve disabling one or both of the cabinet fans, or the chassis fan. Airflow obstruction of external air intake vents can be tested, to determine any effect an obstruction (e.g. 50%) would have on the internal cabinet temperature over time. HVAC system failures can be tested inside a thermal chamber to determine any insulating properties the cabinet provides under a range of typical to extreme conditions, and the point at which the performance of the operating equipment begins to degrade. 
         [0077]    A power system verification (on specific equipment configuration) suite can simulate a rapid site power failure to evaluate the operation of a converter and batteries, simulate a site power return to evaluate the operation of the converter, simulate a gradual drain of site batteries to evaluate the operation of the converter and batteries (e.g. by gradually reducing the input voltage), and simulate a site power return to evaluate the operation of the converter. 
         [0078]    In a preferred embodiment, an enclosure meets the shielding requirements of MIL-STD-188-125-1, and has outside dimensions that do not exceed 26″ wide, 84″ tall, and 22⅜″ deep. These measurements include the door, exterior mounted power line filters, and top seismic bracing, but not door handles, latches, air intake vent(s), or bottom bracing. The internal clear space depth is 19″. The enclosure houses two battery strings (282.4 lbs per string), one battery switch (20-30 lbs), and combined functional electronic equipment (33 lbs). The enclosure has one front door entry having an opening of 23.5″ to accommodate equipment installation and maintenance, a knife edge/copper finger stock EM door seal, and a hinge/latch/handle system that does not buckle, misalign, or degrade over approx 20 year life span when reasonably maintained. The enclosure also includes three shielded waveguide below cutoff fiber entry ports, located on the top of the cabinet, as far forward and to the left as possible, and below the top seismic bracing bar. The enclosure includes two shielded wave guide below cutoff air vents (and fan) that meet MIL-STD-188-125-1 requirements, are constructed of machined, steel material, ¾″ thick with ⅛ inch holes for air flow, and are circumferentially welded per MIL HDBK 423 to the cabinet surface. The enclosure further includes a bottom vent, sized at 7″×16″, and located 12″ off the floor centered on the back wall of the cabinet, as well as a top vent with fan, sized 7″×16″, centered on the back wall, 12″ down from top of cabinet. The enclosure includes two −48 VDC exhaust fans capable of exhausting 320 CFM. Each fan is provided with 6″ of hookup wire for both positive and negative terminals, and has access provisions for maintenance. The enclosure includes internal rails for equipment mounting. There is one rail system per side, each having a tapped front and back face. The forward rail face is located 8″ into the cabinet (usable space), 11″ from the back. The back rail face is located 5″ from the front face. Opposite rails are located 21½″ apart. Rails are tapped ½″ (Typ) and 1¼ (Typ). Opposite mounting holes are be 22 5/16 apart. Holes are punched in a straight, vertical line for ease of equipment installation. Rails are strong enough to support zone 4 activity. A power system for the enclosure includes two 30 Amp 48 VDC, HEMP shielded power line filters, each filter is externally mounted on the top of the cabinet, removable for replacement and accessible for maintenance, includes two power inputs to accommodate two different power feeds (AB) from site power, and is installed in accordance with MIL-HDBK 423 procedures. The power system also includes an external DC power connection to filter input that has four (4) power cables connected to the dirty power inputs on both filters, a specific cable type (#6 power cable (6 AWG, XHHW, Black, Copper, Stranded, 1 Conductor, 600 Volt)), a specific cable length with approximately 4 feet of slack from the cabinet-delivered coiled. The cables enter the cabinet and are bonded to the power terminals of the “dirty” filter compartment. The power system further includes an internal power connection for filter output that has a pre-wired cable from filter output (which terminates inside the cabinet) that is run through a MIL-STD-188-125-1 compliant threaded and gasketed pipe nipple from the “clean” compartment of the power filter into the cabinet. The internal power connection also has a specific cable type (#10 power cable) and a specific cable length with 5 feet of slack delivered coiled. What is more, the power system includes grounding that has a rectangular grounding strip (as apposed to a post), which is roughly 1″ long, 2″ wide and ½″ thick. It is drilled with two ¼ inch holes (tapped for National Course—⅝″ apart center to center), and is welded to the top rear of the cabinet. All items supporting power entry into and exit out of the filter are provided and pre-installed by the enclosure manufacturer. On-site power work involves “butt splicing” site power cables to the #6 cable protruding from the filter (work outside the cabinet) and terminating the #10 power cable to the battery disconnect which feeds power to the distribution panel for the rest of the equipment (work inside the cabinet). The enclosure also includes a base mounting/support that has two solid flanges welded to the front and back of the cabinet, both running the entire width (26″). The support meets Zone 4 stress requirements, has elongated holes in each corner to accommodate floor anchoring bolts. The flanges are narrow but are still be able to accommodate installation of anchoring screws. The enclosure also includes a top seismic support, which has an auxiliary seismic bar structurally connected to the top of the cabinet to meet zone 4 requirements. The support runs parallel to the front and back, and includes (3) holes, three inches apart, tapped for ⅝″ threaded rod. The support accommodates the power line filters and fiber POE mounted on the top of the cabinet. The enclosure batteries sit on two custom made trays (one on top of the other) at the bottom of the cabinet. 
         [0079]    Acceptance testing of an enclosure can encompass a Shielding Effectiveness (SE) testing as well as E1 and E2 Pulse Current Injection (PCI) tests. The SE and PCI testing can be performed in accordance with MIL STD 188-125-1 Appendices A and B, respectively. 
         [0080]    Acceptance Testing of Cabinet—Requirements Met 
         [0081]    In a first test example of an enclosure according to a preferred embodiment of the present invention, the cabinet shielding effectiveness of the enclosure exceeded the magnetic field (H) and electric field (E) performance requirements of the MIL-STD. The filters passed both E1 and E2 pulse current injection testing. The cabinet measured 84″ tall×26″ wide×20″ deep. The cabinet included two vertical supports on the left and right interior for mounting rack equipment. Two HEMP hardened filter boxes were mounted on the top exterior of the cabinet. For the SE test setup, free-space field maps for horizontal and vertical illumination of the cabinet door and sides as well as the roof were made with transmit and receive antennas separated by 1.6 m. The field maps were made with only the ground (earth) present. No metallic objects were nearby. For horizontal illumination of the sides of the cabinet, the receive antenna were rotated at 45 degrees relative to the transmit antenna in order to account for the receive antenna space limitations inside the cabinet under test. The field map for this horizontal configuration included this 45 degree rotation between transmit and receive antennas. For vertical illumination of the sides of the cabinet, the antennas were aligned as is specified in the MIL STD. No rotation off nominal antenna alignment was needed to accommodate fitting the receive antennas inside the cabinet. The field map was performed with the antennas aligned in an up and down configuration wherein the receive antennas were closest to the ground (earth), and the transmit antennas were above, and 1.6 meters away from, the receive antennas. This matched the antenna configuration used to test the roof of the cabinet. The SE measurement was made by subtracting the signal measured on the receive antennas inside the cabinet from the appropriate field map. The result, expressed in DB, is the Shielding Effectiveness. Magnetic field SE was measured from 10 kHz to 20 MHz. Electric field SE was measured from 20 MHz to 1 GHz. A determination of the system measurement range can be made based on the field maps and a noise floor measurement inside the cabinet. The measurement range can provide an upper bound on the shielding effectiveness that can be measured.  FIG. 14  shows the three measurement ranges of the system for the three SE tests. Line  1400  represents the MIL-STD specification. This figure provides data for horizontal rotated 45 degree, vertical, and roof SE measurements for 1.6 m separation. 
         [0082]    A fiber optic based broadband analog receiver can be used inside the cabinet to transmit the signal from the receive antennas back to a network analyzer where it is subsequently digitized and processed via computer. The cabinet can be equipped with a commercial fiber optic feedthrough consisting of a large cylindrical hole in the center of the feedthrough surrounded by a ring of smaller holes in which the fiber is placed in some current systems. It has been discovered that the diameter of the fiber is often be too large to be installed properly in the smaller holes of the feedthrough. Instead, the center plug of the feedthrough can be left out, and RF gasketing material can be placed around the fiber and filling the feedthrough hole. This plug can effectively reproduce the electrical performance of the original center plug. This configuration was maintained throughout SE and PCI testing. 
         [0083]    A total of 10 shielding effectiveness measurements of the cabinet were completed. The cabinet SE performance was found to exceed the requirements of MIL-STD-188-125-1 for all measurements.  FIGS. 15A ,  15 B,  15 C, and  15 D show the horizontal and vertical SE for the cabinet door, left side, rear, and right side respectively (referenced when facing the door of the cabinet). In  FIG. 15A , which shows horizontal and vertical SE measured on the cabinet door, line  1500   a  represents MIL-STD-188-125-1, line  1510   a  represents the horizontal SE, and line  1520   a  represents the vertical SE. In  FIG. 15B , which shows horizontal and vertical SE measured on the cabinet left side, line  1500   b  represents MIL-STD-188-125-1, line  1510   b  represents the horizontal SE, and line  1520   b  represents the vertical SE. In  FIG. 15C , which shows horizontal and vertical SE measured on the cabinet rear, line  1500   c  represents MIL-STD-188-125-1, line  1510   c  represents the horizontal SE, and line  1520   c  represents the vertical SE. In  FIG. 15D , which shows horizontal and vertical SE measured on the cabinet right side, line  1500   d  represents MIL-STD-188-125-1, line  1510   d  represents the horizontal SE, and line  1520   d  represents the vertical SE.  FIG. 15E  shows the two orthogonal SE measurements of the roof. Line  1500   e  represents MIL-STD-188-125-1, line  1510   e  represents the roof  1  SE, and line  1520   e  represents the roof  2  SE. For the SE measurements shown in  FIGS. 15A-15E , the data from a few MHz to 1 GHz is at or near the limit of the measurement range of the test system (shown in  FIG. 14 ). Hence, the actual SE of the cabinet in this frequency range is equal to or greater than that shown in the data. 
         [0084]    The filter PCI setup for this preferred enclosure cabinet embodiment includes four MPE DS33332C 250V 32A HEMP protection filters. Each filter has an EPCOS B60K275 Metal Oxide Varistor (MOV) surge arrester protecting the front end. Pulse current injection (PCI) testing of the four filters involved injecting the filters/MOVs with the E1 and E2 current waveforms specified in MIL STD 188-125-1, and measuring the residual current waveform at the filter outputs into a dummy load as per Appendix B of the MIL STD. All PCI testing of the filters/MOVs was performed with no AC applied. Four drive current levels were used for both E1 and E2, with the fourth level being the full threat level dictated by the MIL-STD. For E1, the drive levels were approximately 70 A, 400 A, 1000 A, and 2500 A. For E2, the drive levels were approximately 3 A, 40 A, 100 A, and 250 A. Wire-to-ground tests were performed on the filters, and the filters were tested one at a time. The local ground on the input of the filter was used as the low side reference for the E1 and E2 pulse generators. For E1 testing the output of the filter under test was terminated in 2 Ohms to the cabinet itself. For E2 testing the output of the filter under test was terminated in 50 Ohms to the cabinet itself. This termination occurred inside the cabinet. 
         [0085]    The residual output current into the 2 or 50 ohm load of the filter was measured using a Pearson inductive current probe, and the resulting voltage waveform out of the current probe was transmitted back to oscilloscopes for digitizing. For the E-1 PCI, this residual current probe signal was transmitted back via an analog fiber link; for the E-2 PCI, this signal was transmitted directly over coaxial cable. The drive signal for the E-1 PCI was measured with a derivative current probe (I-dot) which was transmitted back to the oscilloscope over an analog fiber optic link. The drive signal for the E-2 PCI was measured with a current probe which was transmitted back to the oscilloscope directly over coaxial cable. The digitized current signals (drive and residual) from the oscilloscope were corrected by the computer for effects of the current probe, fiber optic link, and any fixed attenuators used. The resulting time domain waveforms, corrected for instrumentation effects, are described below via an analog fiber link. A pulser can be connected to one of the two filters for testing at the 2500 amp E1 level. 
         [0086]    The filter PCI test results can be described as follows. The filters under test are referenced from the front to rear relative to the door of the cabinet. Therefore, FF1 corresponds to the front filter, L1, FF2 corresponds to the front filter, L2, FR1 corresponds to the rear filter, L1, and FR2 corresponds to the rear filter, L2. In terms of surge arrester testing, standard testing procedures have the surge arrestor protecting the input to the filter tested before and after PCI to ensure no damage to the device has occurred. The EPCOS MOV surge arresters on each filter were tested using a Bourns Model 4010-01 Surge Protector Test Set. This tester supplies a triangular voltage waveform with a rate of rise of 200V per second and a peak voltage of 1000V. When 1 mA of current flow is detected, the tester reports the voltage at which this occurs. Problems with the tester precluded its use for pre-test measurements, but post-test measurements were completed successfully. To obtain a representative pre-test evaluation, a set of 4 identical MOV&#39;s was purchased and tested. The data from the untested sample and post-test results for the installed MOV&#39;s are shown in Table 2 below (EPCOS surge arrester pre-test and post-test performance). 
         [0000]    
       
         
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Surge 
                 Pre-Test Measurement 
                 Post-Test 
               
               
                   
                 Arrester 
                 (untested sample) 
                 Measurement 
               
               
                   
                   
               
             
             
               
                   
                 FR1 
                 441 V 
                 446 V 
               
               
                   
                 FR2 
                 442 V 
                 442 V 
               
               
                   
                 FF1 
                 445 V 
                 441 V 
               
               
                   
                 FF2 
                 442 V 
                 449 V 
               
               
                   
                   
               
             
          
         
       
     
         [0087]    In terms of El test results, the MIL STD 188-125-1 specified E1 risetime and Full Width Half Maximum (FWHM) values are &lt;20 ns and 500-550 ns into a short circuit.  FIG. 16  shows the drive current waveform into a short circuit. This waveform has a peak current of 3000 A. When driving the actual cabinet filter/MOV combination, the delivered peak current was typically 2500-2600 amps (spec is 2500 amps). 
         [0088]    Mil-Std 188-125-1 residual current requirements are: less than 10 A for peak current, less than 1.0e+07 for peak rate of rise, and less than 1.6e−01 for root action. The MIL STD requires that all 3 of the norms be met.  FIG. 17  shows the residuals measured on each of the four filters for the peak 2500 A drive currents. Line  1700  represents FR2, line  1710  represents FF2, line  1720  represents FF2, and line  1730  represents FR1. Table 3 shows that, for this preferred cabinet embodiment, the 4 filters met the required norms for each residual (El residual norms for 2500 A drive). 
         [0000]    
       
         
               
               
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                   
                 Peak Drive 
                 Peak 
                 Peak Rate of Root 
                 Root Action (A 
               
               
                 Filter 
                 Current (A) 
                 Current (A) 
                 Action (A/s) 
                 sqrt(s)) 
               
               
                   
               
             
             
               
                 FR1 
                 2500 A 
                 5.56 
                 8.05e+06 
                 4.76e−02 
               
               
                 FR2 
                 2500 A 
                 6.45 
                 8.02e+06 
                 3.39e−02 
               
               
                 FF1 
                 2500 A 
                 5.78 
                 4.57e+06 
                 4.69e−02 
               
               
                 FF2 
                 2500 A 
                 7.99 
                 5.68e+06 
                 6.49e−02 
               
               
                   
               
             
          
         
       
     
         [0089]    In terms of E2 test results, the MIL STD 188-125-1 specified E2 risetime and Full Width Half Maximum (FWHM) values are &lt;1 us and 3 to 5 ms. It may be difficult to completely capture properly a waveform with such a fast risetime compared to its width on digital oscilloscope.  FIGS. 18 and 19  show the details of the E2 risetime and entire waveform into a short circuit.  FIG. 18  shows the risetime of E2 current pulse into short circuit.  FIG. 19  shows the entire E2 current waveform into short circuit. 
         [0090]    Because MIL-STD-188-125-1 does not contain an explicit residual requirement for E2 current injection, the pass/fail criteria used for acceptance testing in one embodiment is that there be no damage or upset to the filter and its front end surge arrester. The four filters on this preferred cabinet embodiment met the pass requirements for E2 current injection.  FIG. 20  shows the four recorded E2 residuals. Line  2000  represents FR2, line  2010  represents FF2, line  2020  represents FF2, and line  2030  represents FR1. The DSO sweep speed used for the figure was picked to allow a proper capture of the risetime and waveform peak, but only part of the waveform decay. 
         [0091]    In sum, this preferred cabinet embodiment passed the MIL-STD-188-125-1 Appendix A and B Acceptance testing. Appendix A testing included horizontal and vertical measurements of shielding effectiveness on all four sides and the roof of the cabinet. Appendix B testing included E1 and E2 current waveforms injected into the filters at increasing amplitudes up to and including the 2500 A threat level for wire-to-ground for E1 and 250 A for E2. 
         [0092]    Acceptance Testing of Cabinet—Requirements Not Met 
         [0093]    The following description provides test results for a cabinet that did not meet certain accepting testing requirements. Testing included the Shielding Effectiveness (SE) as well as E1 and E2 Pulse Current Injection (PCI) tests. The SE and PCI testing were performed in accordance with MIL STD 188-125-1 Appendices A and B, respectively. The cabinet initially failed horizontal SE testing on all four sides. Also, both orthogonal SE measurements of the roof failed. An examination of the cabinet found that the door hinges were out of position. After the door was repositioned, the left side of the cabinet was re-tested. The horizontal SE was found to pass with only a few dB of margin. No further re-testing was performed. The filters passed both E1 and E2 pulse current injection testing. 
         [0094]    The cabinet measured 84″ tall×26″ wide×20″ deep. The cabinet included two vertical supports on the left and right interior for mounting rack equipment. There were two HEMP hardened filter boxes mounted on the top exterior of the cabinet, each containing two filters. The HEMP hardened side of these boxes feed directly into the cabinet. The cabinet included a hole drilled through it at the lower right corner of the cabinet left side. This hole had been installed to accommodate an RF-feedthrough used in testing prior to DTRA receiving the cabinet. This hole was sealed using a two fiat washers, two RF gaskets, and a nut and bolt. The gasket was placed on either side of the cabinet wall, covered with the washers, and tightened down with the nut and bolt. 
         [0095]    For the SE test setup, free-space field maps for horizontal and vertical illumination of the cabinet door and sides as well as the roof were made with transmit and receive antennas separated by 1.6 m. These field maps were made with only the ground (earth) present—no metallic objects were nearby. For horizontal illumination of the sides of the cabinet, the receive antenna needed to be rotated at 45 degrees relative to the transmit antenna in order to account for the receive antenna space limitations inside the cabinet under test. The field map for this horizontal configuration included this 45 degree rotation between transmit and receive antennas. For vertical illumination of the sides of the cabinet, the antennas were aligned as is specified in the MIL STD. No rotation off nominal antenna alignment was needed to accommodate fitting the receive antennas inside the cabinet. For the illumination of the roof of the cabinet, no rotation of the antennas was required. The field map, however, was performed with the antennas aligned in an up and down configuration wherein the receive antennas were closet to the ground (earth), and the transmit antennas were above, and 1.6 meters away from, the receive antennas. This matched the antenna configuration used to test the roof of the cabinet. An SE measurement was made by subtracting the signal measured on the receive antennas inside the cabinet from the appropriate field map. The result, expressed in DB is the Shielding Effectiveness. Magnetic field SE was measured from 10 kHz to 20 MHz. Electric filed SE was measured from 20 MHz to 1 GHz. Using these field maps, and using a noise floor measurement inside the cabinet, a determination of the system measurement range can be made. This measurement range provides an upper bound on the shielding effectiveness that can be measured.  FIG. 21  shows the three measurement ranges of the DTRA system for the three SE tests (horizontal rotated 45 degrees, vertical, and roof SE measurement ranges for 1.6 m separation). Line  2100  represents the MIL-STD specification. 
         [0096]    A fiber optic based broadband analog receiver is used inside the cabinet to transmit the signal from the receive antennas back to a network analyzer where it is subsequently digitized and processed via computer. The cabinet was equipped with a commercial fiber optic feedthrough consisting of a large cylindrical hole in the center of the feedthrough surrounded by a ring of smaller holes in which the fiber is currently placed in some systems. The diameter of the fiber was found to be too large to be installed properly in the smaller holes of the feedthrough and still allow the center plug to be completely installed. Instead, the center plug of the feed through was inserted as far as possible, and RF gasketing material was placed around the fiber and filling the rest of the feedthrough hole. A metal cap was fabricated and installed which further capped these holes on the exterior of the cabinet. This plug effectively reproduced the electrical performance of the original center plug. This configuration was maintained throughout SE and PCI testing. 
         [0097]    In terms of SE test results, during initial SE testing of this cabinet, the horizontal SE measurements were found to fail at the high frequency end of the test spectrum for all four sides. An examination of the cabinet found that the hinges holding the door on the cabinet had worked loose. Eight shielding effectiveness measurements of this cabinet were completed on the four sides, four horizontal and vertical, as well as the two orthogonal measurements of the roof, prior to correcting the hinge problem. After correction, a horizontal SE measurement of the left side of the cabinet was repeated, and the cabinet was found to pass with only a few dB of margin. No other SE re-tests were performed. 
         [0098]      FIGS. 22A ,  22 B,  22 C, and  22 D show the horizontal and vertical SE for the cabinet door, left side, rear, and right side respectively, before the door was repaired. In  FIG. 22A , which shows horizontal and vertical SE measured on the cabinet door, line  2200   a  represents MIL-STD-188-125-1, line  2210   a  represents the horizontal SE, and line  2220   a  represents the vertical SE. In  FIG. 22B , which shows horizontal and vertical SE measured on the cabinet left side, line  2200   b  represents MIL-STD-188-125-1, line  2210   b  represents the horizontal SE, and line  2220   b  represents the vertical SE. In  FIG. 22C , which shows horizontal and vertical SE measured on the cabinet rear, line  2200   c  represents MIL-STD-188-125-1, line  2210   c  represents the horizontal SE, and line  2220   c  represents the vertical SE. In  FIG. 22D , which shows horizontal and vertical SE measured on the cabinet right side, line  2200   d  represents MIL-STD-188-125-1, line  2210   d  represents the horizontal SE, and line  2220   d  represents the vertical SE.  FIG. 22E  shows the two orthogonal SE measurements of the roof. Line  2200   e  represents MIL-STD-188-125-1, line  2210   e  represents the roof  1  SE, and line  2220   e  represents the roof  2  SE. Some of the SE measurements at the higher frequencies, as shown in  FIGS. 22A-22E , can be seen to be essentially at the limit of the measurement range of the test system (shown in  FIG. 21 ). This means that the actual SE of the cabinet at these frequencies is equal to or greater than that shown in the data. 
         [0099]    After completion of the original SE test measurement set, the door was realigned on the cabinet. Testing was performed on the cabinet with the repaired door. The left side of the cabinet was chosen for re-test since in the original data this side represented the worst failure.  FIG. 23  shows the results of the post-door fix horizontal SE measurement. Line  2300  represents MIL-STD-188-125-1, and line  2310  represents the horizontal SE. As can be seen when compared to  FIG. 22B  there is improvement in SE across the entire frequency test range. 
         [0100]    For the filter PCI test setup, this cabinet has four MPE DS33332C 250V 32A HEMP protection filters. Each filter has an EPCOS 1360K275 Metal Oxide Varistor (MOV) surge arrester protecting the front end. Pulse current injection (PCI) testing of the four filters involved injecting the filters/MOVs with the E1 and E2 current waveforms specified in MIL STD 188-125-1, and measuring the residual current waveform at the filter outputs into a dummy load as per Appendix B of the MIL STD. All PCI testing of the filters/MOVs was performed with no AC applied. Four drive current levels were used for both E1 and E2, with the fourth level being the full threat level dictated by the MIL-STD. For E1, the drive levels were approximately 70 A, 400 A, 1000 A, and 2500 A. For E2, the drive levels were approximately 3 A, 40 A, 100 A, and 250 A. Only wire-to-ground tests were performed on the filters, and the filters were tested one at a time. The local ground on the input of the filter was used as the low side reference for the E1 and E2 pulse generators. For E1 testing each filter was terminated in 2 Ohms to the cabinet itself For E2 testing each filter was terminated in 50 Ohms, also to the cabinet itself. This termination occurs inside the cabinet. The residual output current into the 2 or 50 ohm load of the filter was measured using a Pearson inductive current probe, and the resulting voltage waveform out of the current probe was transmitted back to oscilloscopes for digitizing. For the E-1 PCI, this residual current probe signal was transmitted back via an analog fiber link; for the E-2 PCI, this signal was transmitted directly over coaxial cable. The drive signal for the E-1 PCI was measured with a derivative current probe (I-dot) which was transmitted back to the oscilloscope over an analog fiber optic link. The drive signal for the E-2 PCI was measured with a current probe which was transmitted back to the oscilloscope directly over coaxial cable. The digitized current signals (drive and residual) from the oscilloscope were corrected by the computer for effects of the current probe, fiber optic link, and any fixed attenuators used. The resulting time domain waveforms, corrected for instrumentation effects, are shown in Section, 6.2. via an analog fiber link.  FIG. 11  below shows the pulser connected to one of the two filters for testing. 
         [0101]    In terms of the filter PCI test results, the filters under test are referenced from the left to right relative to the door of the cabinet. Therefore, FLU corresponds to the left filter, L1, FLL2 corresponds to the left filter, L2, FRL1 corresponds to the right filter, L1, and FRL2 corresponds to the right filter, L2. For the surge arrester testing, standard testing procedures have the surge arrestor protecting the input to the filter tested before and after PCI to ensure no damage to the device has occurred. The EPCOS MOV surge arresters on each filter were tested using a Bourns Model 4010-01 Surge Protector Test Set. This tester supplies a triangular voltage waveform with a rate of rise of 200V per second and a peak voltage of 1000V. When 1 mA of current flow is detected, the tester reports the voltage at which this occurs. These 4 MOVs were tested before injection of the E-2 pulses and again after injection of the E-1 pulses. For comparison, a set of 4 identical MOV&#39;s was purchased and tested for their breakdown voltage (these MOVs were not pulsed). The data from the un-pulsed samples, the pre-E2 test results, and post E-2 test results for the installed. MOV&#39;s are shown in Table 4 below (EPCOS surge arrester pre-test and post-test performance compared to untested MOVs). 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 4 
               
               
                   
               
               
                 Surge 
                 Pre-Test Measurement 
                 Pre-E2 Test 
                 Post-E2 Test 
               
               
                 Arrester 
                 (untested sample) 
                 Measurement 
                 Measurement 
               
               
                   
               
             
             
               
                 FLL1 
                 441 V 
                 438 V 
                 446 V 
               
               
                 FLL2 
                 442 V 
                 433 V 
                 440 V 
               
               
                 FRL1 
                 445 V 
                 440 V 
                 446 V 
               
               
                 FRL2 
                 442 V 
                 422 V 
                 428 V 
               
               
                   
               
             
          
         
       
     
         [0102]    For the E1 test results, the MIL STD 188-125-1 specified El risetime and Full Width Half Maximum (FWHM) values are &lt;20 ns and 500-550 ns into a short circuit.  FIG. 24  shows the E1 drive current waveform into a short circuit. This waveform has a peak current of 3000 A. When driving the actual filter/MOV combination of this cabinet, the delivered peak current was typically 2500-2600 amps (spec is 2500 amps). MIL-STD-188-125-1 residual current requirements are: less than 10 A peak current, less than 1.0e+07 for peak rate of rise, and less than 1.6e−01 for root action. The MIL STD requires that all 3 of the norms be met.  FIG. 24  shows the residuals measured on each of the four filters for the peak 2500 A drive currents. Table 5 shows that all 4 filters met all of the required norms for each residual.  FIG. 25  shows the residuals measured on each of the four filters for the peak 2500 A drive currents. Line  2500  represents FRL2, line  2510  represents FLL2, line  2520  represents FRL1, and line  2530  represents FLL1. Table 5 shows the norms for each residual (E1 residual norms for 2500 A drive). The spec requirements are less than 10 A for peak current, less than 1.0e+07 for peak rate of rise, and less than 1.6e−01 for root action. 
         [0000]    
       
         
               
               
               
               
               
             
           
               
                 TABLE 5 
               
               
                   
               
               
                   
                 Peak Drive 
                 Peak 
                 Peak Rate of 
                 Root Action (A 
               
               
                 Filter 
                 Current (A) 
                 Current (A) 
                 Rise (A/s) 
                 sqrt(s)) 
               
               
                   
               
             
             
               
                 FLL1 
                 2500 A 
                 2.49 
                 9.63e+05 
                 5.44e−02 
               
               
                 FLL2 
                 2500 A 
                 2.35 
                 1.13e+06 
                 3.40e−02 
               
               
                 FRL1 
                 2500 A 
                 2.36 
                 1.16e+06 
                 5.25e−02 
               
               
                 FRL2 
                 2500 A 
                 2.12 
                 1.40e+06 
                 4.53e−02 
               
               
                   
               
             
          
         
       
     
         [0103]    For the E2 test results, the MIL STD 188-125-1 specified E2 risetime and Full Width Half Maximum (FWHM) values are &lt;1 us and 3 to 5 ms. It may be difficult to completely capture properly a waveform with such a fast risetime compared to its width on digital oscilloscope.  FIGS. 26 and 27  show the details of the E2 risetime and entire waveform into a short circuit.  FIG. 26  shows the risetime of E2 current pulse into short circuit.  FIG. 27  shows the entire E2 current waveform into short circuit. 
         [0104]    Because MIL-STD-188-125-1 does not contain an explicit residual requirement for E2 current injection, the pass/fail criteria used for acceptance testing in one embodiment is that there be no damage or upset to the filter and its front end surge arrester. The four filters on this cabinet met the pass requirements for E2 current injection.  FIG. 28  shows the four recorded E2 residuals (for 250 A drive). The DSO sweep speed used for the figure was picked to allow a proper capture of the risetime and waveform peak, but only part of the waveform decay. Line  2800  represents FRL2, line  2810  represents FRL1, line  2820  represents FLL2, and line  2830  represents FLL1. 
         [0105]    In sum, this cabinet only marginally meets the performance requirements of MILSTD-188-125-1. As delivered, the cabinet failed the shielding effectiveness tests at the high end of the frequency band. With adjustment to the door, the worst SE measurement was repeated and found to barely meet the requirements of the standard. The filters met the PCI requirements of the standard, but due to the residual acceptance may not be warranted. The root cause of the failure of the cabinet seems to reside with the design of the door and its method of attachment to the cabinet. Without significant redesign of the RF contact around the door it may not be possible for this design to deliver a −20 dB or greater margin above the specification. 
       DP Model 
       [0106]      FIGS. 29A-29C  illustrate various views of a HEMP protected telecommunications enclosure  2900  according to embodiments of the present invention. Telecommunications enclosure  2900  includes a cabinet  2910  having a top  2920 , a bottom  2930 , a front  2940 , a back  2950 , and two sides  2960 . Cabinet  2910  defines an interior space  2970 , and is coupled with a door  2980  via a hinge assembly  2982 . When door  2980  is closed, it can be securely fastened to cabinet  2910  with latch assembly  2984 . Typically, door  2980  is wide enough to accommodate installation and routine maintenance of equipment housed in cabinet  2910 , and robust enough to provide adequate shielding. Enclosure  2900  also includes an air exhaust system  2922  disposed toward back  2950  of cabinet  2910 . Exhaust system  2922  may include, for example, six fans located toward cabinet top  2920  and accessible for maintenance and repair. As shown in  FIGS. 29B  and C, exhaust system  2922  can vent out the back of the cabinet. In some embodiments, exhaust system  2922  vents out the back of the cabinet, toward the top. Enclosure  2900  includes rack components such as vertical mounting rails or tapped mounting angles  2962  and chassis supports  2964  coupled with cabinet sides  2960 . Enclosure  2900  may also include an air intake system  2952 , a power filter system  2954 , a fiber optic cable point of entry (POE)  2924 , and a power input point of entry (not shown), each coupled with back  2950 , side  2960 , or top  2920  of cabinet  2910 . In some embodiments, interior cables from a filter system are clean and exterior cables from a filter system are dirty. In some cases, power filter system  2954  is configured to deliver  30  amps into the cabinet. 
         [0107]    Enclosure  2900  or component parts thereof are typically configured to certain specifications or dimensions. For example, the enclosure can be configured for installation in a standard telecommunications room or space, such that the dimensions of the enclosure do not exceed certain limits. In some cases, enclosure  2900  can be manufactured not to exceed a volume or space of about 26″ width by about 38″ depth by about 84″ height. This may include the frame or relay rack size, including panel covers. The enclosure can include two vertical mounting rails on each side. This particular configuration is useful for enclosures that hold telecommunications equipment. Enclosures that hold computer servers may provide a different mounting rail configuration. The rails can be manufactured from 12 Gauge steel, and can include holes which may be tapped according to an American National Standard. For example, in some embodiments, the rails are tapped with 12-24 National Coarse (NC) holes along their entire length or one or more portions thereof The holes may be punched so that they are aligned in a straight vertical line, which can allow for ease of telecommunications equipment installation. In some cases, enclosure elements such as the vertical mounting rails are configured to meet or exceed seismic standards. For example, the rails can be manufactured to meet a Zone 4 seismic specification. Typically a cabinet includes four vertical mounting rails. Embodiments of the present invention include enclosures and component elements thereof that are constructed according to certain procedures or standard specifications such as MIL-HDBK-423. In some embodiments, enclosure  2900  is configured for placement in a but or prefabricated building located along a telecommunications backbone, at least part of which may be near a railroad grid or right-of-way. 
         [0108]    Enclosure  2900  can define an electromagnetic barrier, so as to prevent or limit HEMP fields and conducted transients from entering the enclosed space. In some cases, enclosure  2900  complies with minimum requirements or design objects as set forth in certain standards, such as MIL-STD-188-125-1 (including Appendices), which is a standard for high-altitude electromagnetic pulse (HEMP) protection for ground-based facilities performing critical, time-urgent missions. For example, embodiments of the present invention encompass enclosures and component parts that provide at least about 80 dB attenuation at 1 GHz. In some embodiments, enclosures and component parts provide at least about 100 dB attenuation at 1 GHz. Enclosure  2900  and components thereof can also comply with safety, spatial and environmental design guidelines applied to telecommunications equipment, such as NEBS™. Similarly, enclosure  2900  and components thereof can comply with documents such as Telcordia Technologies GR-63-CORE and GR-1089-CORE, as well as related standards required by or developed by organizations such as FCC, CISPR, IEC, IEEE, ASTM, ANSI, and ETSI. The fiber optic cable point of entry can include a shielded wave guide, and in some cases is located on the top of the enclosure, toward the front, so as to allow for ease of internal cable management. In some cases, an air intake system includes a shielded passive vent, which may be constructed of machined, steel honeycomb. The vent can be circumferentially welded to a mounting surface or cabinet surface according to a procedure or standard specification such as MIL-HDBK-423. 
         [0109]    Enclosure  2900  is well suited for use in TEMPEST applications for inhibiting or reducing compromising emanations or other unintentional intelligence-bearing signals that may be transmitted by or received from components contained within the enclosure. Such emanations or radiation can include electrical, mechanical, or acoustical energy signals. 
       DW Model 
       [0110]      FIGS. 30A-30C  illustrate various views of a HEMP protected telecommunications enclosure  3000  according to embodiments of the present invention. Telecommunications enclosure  3000  includes a cabinet  3010  having a top  3020 , a bottom  3030 , a front  3040 , a back  3050 , and two sides  3060 . Cabinet  3010  defines an interior space  3070 , and is coupled with a right door  3080 R via a right hinge assembly  3082 R and a left door  3080 L via a left hinge assembly  3082 L. When doors  3080 R,  3080 L are closed, they can be securely fastened to cabinet  3010  with latch assemblies  3084 R,  3084 L, respectively. Typically, doors  3080 R,  3080 L are wide enough to accommodate installation and routine maintenance of equipment housed in cabinet  3010 , and robust enough to provide adequate shielding. Enclosure  3000  also includes a air exhaust systems  3022 R and  3022 L disposed toward back  3050  of cabinet  3010 . Exhaust systems  3022 R,  3022 L may each include, for example, six fans located toward cabinet top  3020  and accessible for maintenance and repair. In some cases, exhaust systems  3022 R,  3022 L vent out the back of the cabinet. In some cases, the enclosure may include exhaust systems  3023 L that vent out the top of the cabinet. Optionally, exhaust systems  3022 R,  3022 L vent out the back of the cabinet, toward the top. Enclosure  3000  includes rack components such as vertical mounting rails or tapped mounting angles  3062  and chassis supports coupled with cabinet sides  3060 . Enclosure  3000  also includes an air intake systems  3052 R,  3052 L, a power filter system  3054 , a fiber optic cable point of entry (POE)  3024 , and a power input point of entry (POE)  3026 , each coupled with back  3050 , side  3060 , or top  3020  of cabinet  3010 . In some embodiments, interior cables from a filter system are clean and exterior cables from a filter system are dirty. In some cases, power filter system  3054  includes redundant components. In some cases, power filter system  3054  includes one or more DC circuits. 
         [0111]    Enclosure system  3000  may include an ox bar support or seismic brace  3009  coupled with an upper portion of the cabinet. Such seismic braces can be coupled with a ceiling of a building or other structure, and can help to stabilize the enclosure in the event of an earthquake. As shown here, enclosure system  3000  may also include a side floor brace  3011 , which can similarly be useful in stabilizing the enclosure. Enclosure  3000  can also include a finger stock that engages the door. For example, enclosure cabinet  3010  can include a knife edge finger stock  3081 L disposed around a left door opening  3012  of the cabinet, such that door  3080 L fits against the finger stock when the door is in a closed configuration. Although the cabinet may include two doors or two door openings, in some cases left-side interior and the right-side interior of the cabinet will be open toward one another. For example, there may or may not be a middle wall or partition separating the two sides of the interior space  3070 . Enclosure system  3000  may include a site ground  3053 , which can operate to ground the cabinet or enclosure system. In some cases, power filter system  3054  is configured to deliver or transmit 100 amps into the cabinet. 
         [0112]    Enclosure  3000  or component parts thereof are typically configured to certain specifications or dimensions. For example, the enclosure can be configured for installation in a standard telecommunications room or space, such that the dimensions of the enclosure do not exceed certain limits. In some cases, enclosure  3000  can be manufactured not to exceed a volume or space of about 65″ width by about 30″ depth by about 84″ height. This may include the frame or relay rack size, including panel covers. The enclosure can include two vertical mounting rails on each side. This particular configuration is useful for enclosures that hold telecommunications equipment. Enclosures that hold computer servers may provide a different mounting rail configuration. The rails can be manufactured from 12 Gauge steel, and can include holes which may be tapped according to an American National Standard. For example, in some embodiments, the rails are tapped with 12-24 National Coarse (NC) holes along their entire length or one or more portions thereof The holes may be punched so that they are aligned in a straight vertical line, which can allow for ease of telecommunications equipment installation. In some cases, enclosure elements such as the vertical mounting rails are configured to meet or exceed seismic standards. For example, the rails can be manufactured to meet a Zone 4 seismic specification. Typically a cabinet includes four vertical mounting rails. Embodiments of the present invention include enclosures and component elements thereof that are constructed according to certain procedures or standard specifications such as MIL-HDBK-423. In some embodiments, enclosure  3000  is configured for placement in a but or prefabricated building located along a telecommunications backbone, at least part of which may be near a railroad grid or right-of-way. 
         [0113]    Enclosure  3000  can define an electromagnetic barrier, so as to prevent or limit HEMP fields and conducted transients from entering the enclosed space. In some cases, enclosure  2900  complies with minimum requirements or design objects as set forth in certain standards, such as MIL-STD-188-125-1 (including Appendices), which is a standard for high-altitude electromagnetic pulse (HEMP) protection for ground-based facilities performing critical, time-urgent missions. For example, embodiments of the present invention encompass enclosures and component parts that provide at least about 80 dB attenuation at 1 GHz. In some embodiments, enclosures and component parts provide at least about 100 dB attenuation at 1 GHz. Enclosure  3000  and components thereof can also comply with safety, spatial and environmental design guidelines applied to telecommunications equipment, such as NEBS™. Similarly, enclosure  3000  and components thereof can comply with documents such as Telcordia Technologies GR-63-CORE and GR-1089-CORE, as well as related standards required by or developed by organizations such as FCC, CISPR, IEC, IEEE, ASTM, ANSI, and ETSI. The fiber optic cable point of entry can include a shielded wave guide, and in some cases is located on the top of the enclosure, toward the front, so as to allow for ease of internal cable management. In some cases, an air intake system includes a shielded passive vent, which may be constructed of machined, steel honeycomb. The vent can be circumferentially welded to a mounting surface or cabinet surface according to a procedure or standard specification such as MIL-HDBK-423. 
       CS Model 
       [0114]      FIGS. 31A-31C  illustrate various views of a HEMP protected telecommunications enclosure  3100  according to embodiments of the present invention. Telecommunications enclosure  3100  includes a cabinet  3110  having a top  3120 , a bottom  3130 , a front  3140 , a back  3150 , and two sides  3160 . Cabinet  3110  defines an interior space  3170 , and is coupled with a door  3180  via a hinge assembly  3182 . When door  3180  is closed, it can be securely fastened to cabinet  3110  with latch assembly  3184 . Typically, door  3180  is wide enough to accommodate installation and routine maintenance of equipment housed in cabinet  3110 , and robust enough to provide adequate shielding. Enclosure  3100  also includes an air exhaust system  3122  disposed toward back  3150  of cabinet  3110 . Exhaust system  3122  may include, for example, two fans located toward cabinet top  3120  and accessible for maintenance and repair. In some cases, exhaust system  3122  vents out the back of the cabinet. In a preferred embodiment, exhaust system  3122  vents out the back of the cabinet, toward the top. Enclosure  3100  includes rack components such as vertical mounting rails or tapped mounting angles  3162  and chassis supports coupled with cabinet sides  3160 . Enclosure  3100  also includes an air intake system  3152 , a power filter system  3154 , a fiber optic cable point of entry (POE)  3124 , and a power input point of entry (POE)  3126 , each coupled with back  3150 , sides  3160 , or top  3120  of cabinet  3110 . In some embodiments, interior cables from a filter system are clean and exterior cables from a filter system are dirty. In some cases, power filter system  3154  is configured to deliver or transmit 30 amps into the cabinet. Optionally, the exhaust and intake assemblies can be switched, so that air intake system  3152  is disposed toward the upper portion of the cabinet, and exhaust system  3122  is disposed toward the lower portion of the cabinet. 
         [0115]    Enclosure  3100  or component parts thereof are typically configured to certain specifications or dimensions. For example, the enclosure can be configured for installation in a standard telecommunications room or space, such that the dimensions of the enclosure do not exceed certain limits. In some cases, enclosure  3100  can be manufactured not to exceed a volume or space of about 26″ width by about 20¼″ depth by about 84″ height. This may include the frame or relay rack size, including panel covers. The enclosure can include two vertical mounting rails on each side. This particular configuration is useful for enclosures that hold telecommunications equipment. Enclosures that hold computer servers may provide a different mounting rail configuration. The rails can be manufactured from 12 Gauge steel, and can include holes which may be tapped according to an American National Standard. For example, in some embodiments, the rails are tapped with 12-24 National Coarse (NC) holes along their entire length or one or more portions thereof The holes may be punched so that they are aligned in a straight vertical line, which can allow for ease of telecommunications equipment installation. In some cases, enclosure elements such as the vertical mounting rails are configured to meet or exceed seismic standards. For example, the rails can be manufactured to meet a Zone 4 seismic specification. Typically a cabinet includes four vertical mounting rails. Embodiments of the present invention include enclosures and component elements thereof that are constructed according to certain procedures or standard specifications such as MIL-HDBK-423. In some embodiments, enclosure  3100  is configured for placement in a but or prefabricated building located along a telecommunications backbone, at least part of which may be near a railroad grid or right-of-way. 
         [0116]    Enclosure  3100  can define an electromagnetic barrier, so as to prevent or limit HEMP fields and conducted transients from entering the enclosed space. In some cases, enclosure  3100  complies with minimum requirements or design objects as set forth in certain standards, such as MIL-STD-188-125-1 (including Appendices), which is a standard for high-altitude electromagnetic pulse (HEMP) protection for ground-based facilities performing critical, time-urgent missions. For example, embodiments of the present invention encompass enclosures and component parts that provide at least about 80 dB attenuation at 1 GHz. In some embodiments, enclosures and component parts provide at least about 100 dB attenuation at 1 GHz. Enclosure  3100  and components thereof can also comply with safety, spatial and environmental design guidelines applied to telecommunications equipment, such as NEBS™. Similarly, enclosure  3100  and components thereof can comply with documents such as Telcordia Technologies GR-63-CORE and GR-1089-CORE, as well as related standards required by or developed by organizations such as FCC, CISPR, IEC, IEEE, ASTM, ANSI, and ETSI. The fiber optic cable point of entry can include a shielded wave guide, and in some cases is located on the top of the enclosure, toward the front, so as to allow for case of internal cable management. In some cases, an air intake system includes a shielded passive vent, which may be constructed of machined, steel honeycomb. The vent can be circumferentially welded to a mounting surface or cabinet surface according to a procedure or standard specification such as MIL-HDBK-423. 
         [0117]    Enclosure system  3100  can also include an alarm or door sensor assembly  3101  that is configured to send an alarm signal to an alarm center  3105  or control center, so as to provide an alert in the event of unauthorized access to the cabinet enclosure. In some cases, door sensor  3101  may transmit a signal to an automatic built-in test equipment assembly  3113  that is configured to stop a radiation test in the event the door is opened. In some cases, enclosure system  3100  can include one or more spools  3102  for storing or managing cabling. Optionally, enclosure system  3100  may include a DC/DC converter  3107  that separates outside or external site power from internal batteries. During normal usage, telecommunication equipment contained within the cabinet is typically powered by an external or site source. If the site power is interrupted, for example due to an EMP event, then converter  3107  can facilitate the delivery of battery power to the telecommunications equipment. Optionally, converter  3107  can facilitate the delivery of site power to the telecommunications equipment after site power is restored. Hence, telecommunication equipment within the enclosure can be configured to be fed or powered by site power, as well as battery power. Converter  3107  can operate to isolate the enclosure from the site until site power is established. Converter  3107  can also operate to prevent or inhibit the transfer of power from the batteries to the site, so that the batteries do not feed or provide power to the site, thus preserving the battery power for operational needs of the telecommunications equipment within the enclosure. In some cases, enclosure  3100  includes a battery disconnect  3108  that electronically disconnects batteries from the telecommunication components, so as to allow an operator or technician to service various aspects of the enclosure. As shown in  FIG. 31B , enclosure  3000  may also include power cables  3103  and a ground cable  3104 . 
         [0118]      FIG. 32  shows an exemplary Anderson plug assembly  3200  coupled with a cabinet mounting rail assembly  3210  according to embodiments of the present invention. As depicted here, Anderson plug assembly  3200  can include a first plug  3202  coupleable with a second plug  3204 . The plug assembly can be mounted on a vertical rail  3210  via an L-bracket or other mounting assembly  3230 . The incorporation of Anderson plug assemblies into an enclosure system can allow for modular type maintenance of the enclosure. For example, plug assemblies can be used to isolate telecommunications equipment from a power source or other components of an enclosure. Moreover, such plug assemblies enable a technician or operator to quickly disconnect and swap out telecommunication components or other electronic mechanisms within the enclosure during a maintenance procedure. In this way, the plug assemblies can facilitate a simplified approach to operational management of the enclosure 
         [0119]      FIG. 33  shows a spool assembly  3300  according to embodiments of the present invention. Spool assembly  3300  may include an inner support  3310  having one or more radially outward projecting tabs  3312 , and an outer support  3320  having one or more radially inward projecting tabs  3322 . As shown here, outer support  3320  is coupled with a sidewall  3360  of an enclosure cabinet. In use, a portion of a cable  3340  can be wrapped around the inner support, and held in place by the outward and inward projecting tabs. Spool assembly  3300  allows a technician or operator to manage fiber or cable slack within a cabinet. For example, extra cabling can be wrapped around the spool. 
         [0120]      FIG. 34  shows a hinge assembly  3400  of an enclosure according to embodiments of the present invention. The hinge assembly presents a low profile while accommodating a door and knife edge combination that is sufficiently deep to provide HEMP protection. As shown here, hinge assembly  3400  includes a stile  3410 , a pin  3420 , and a leaf  3430 . Door hinge stile  3410  can have a tube length TL of about 3 inches and a tube width TW of about 1 inch. Stile  3410  can also have a cylinder outer diameter OD of about 1.5 inches and a cylinder inner diameter of about 0.5 inches. Hinge pin  3420  can have a length of about 5.225 inches and an outer diameter of about 0.5 inches. Door hinge leaf  3430  can include a shim  3232  having a length of about 8 inches and a width of about 4 inches. Door hinge leaf  3430  can also include a support  3434  having a main section  3434   a , a central section  3434   b , and a cylinder section  3434   c . Main section  3434   a  has a length L of about 10 inches, a width W of about 4 inches, and a thickness T of about 0.25 inches. Central section  3434   b  can have a length of about 1 inch. As shown here, main section  3434   a  and central section  3434   b  can define an angle a of about 40 degrees. 
         [0121]    Enclosures disclosed herein are well suited for use in containing or protecting supervisory control and data acquisition (SCADA) systems or components. In some cases, enclosures can be used to protect aspects of industrial, infrastructure, or facility-based control systems or processes. Optionally, enclosures can be used to hold programmable logic controllers (PLCs), or elements of utility or power generations systems. 
         [0122]    In some instances, a particular enclosure embodiment disclosed herein may incorporate one or more features of another enclosure embodiment. For example, a CS Model enclosure can have a door that is the same size as a door of a DP Model. Relatedly, different enclosure embodiments can be configured to house different types of telecommunications or electronic equipment. Exemplary enclosures may include a power connection assembly disposed toward the front of the enclosure or cabinet. 
         [0123]    Enclosures can be used to house equipment within repeater huts that are located along railroad lines. In some cases, enclosures can be configured to fit within standard bay spaces. Enclosures may contain one or more linked amplifiers that transmit signals from one repeater but to another, or from a repeater but to a larger terminal unit. For example, signals or information can be transmitted along a link of amplifiers to a terminal unit, wherein the signal is regenerated or boosted. In some cases, CS Models can be placed within repeater huts. Enclosures may also be used to house equipment contained within a larger site, such as a building or warehouse. 
         [0124]    Although certain system, device, and method embodiments have been disclosed herein, it will be apparent from the foregoing disclosure to those skilled in the art that variations, modifications, alternative constructions, and equivalents of such embodiments may be made without departing from the true spirit and scope of the invention. Therefore, the above description should not be taken as limiting the scope of the invention which is defined by the appended claims.