Patent Publication Number: US-8526200-B2

Title: Connection lug

Description:
The present application is a divisional of U.S. patent application Ser. No. 13/301,720, entitled OVERVOLTAGE PROTECTION SYSTEM FOR WIRELESS COMMUNICATION SYSTEMS, filed Nov. 21, 2011 that claims priority to U.S. Provisional Application No. 61/440,609, entitled MODULAR OVERVOLTAGE PROTECTION SYSTEM FOR WIRELESS COMMUNICATION SYSTEMS, filed Feb. 8, 2011; and is a continuation-in-part of U.S. application Ser. No. 12/984,304, entitled OVERVOLTAGE PROTECTION FOR REMOTE RADIO HEAD-BASED WIRELESS COMMUNICATION SYSTEMS, filed Jan. 4, 2011 that claims priority to U.S. Provisional Application No. 61/363,967, filed Jul. 13, 2010; which are all herein incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     Latest generation wireless communications systems, referred to as distributed antenna systems (DAS), distributed DC radio systems, remote radio heads (RRH), 4G and long term evolution (LTE) cellular communication systems, now commonly locate the radios next to the antennas on the tower outside of the communications shelter. In these next-generation facilities, the baseband system module that controls the radio traffic is still located at the ground level shelter, but the actual radios are separated from the controllers up to several hundred feet and controlled by fiber optic links. The radios are powered directly by DC feeds from the DC power plant that extend up the tower and to the radios. In some cases, the DC cables and fiber optic cables are run separately up the tower and in other cases they are all bundled together in one large hybrid cable. 
     The radios located outside of the communications shelter on top of the tower are much more susceptible to damage from lighting strikes and other electrical power surge events. Individual power lines are run to each individual radio also increasing the amount of power cabling exposed to power surge events. Thus, the DC power plant and telecommunication equipment at communication stations with distributed power have more risk of being damaged due to direct lighting strikes and power surges. 
     OVERVIEW 
     A rack mountable surge suppression unit provides local in-line surge suppression protection for the electrical equipment located in the communication station. A unique surge suppression tray is hot swappable so that multiple surge suppression devices can be replaced at the same time without disrupting radio operation. A connection panel in the rack mountable surge suppression unit provides a common relatively short in-line contact point between the surge suppression devices in the tray and different power cables that are distributed out to the different radios. 
     Individual connection lugs may be used in the connection panel. The connection lugs provide a unique in-line pluggable interface between the surge suppression tray and the connection panel that allow the surge suppression devices to be insertably attached to the power cables. The connection lugs also allow the power cables to be more easily inserted and attached to the connection panel in a reduced front face footprint. The connection lugs are not limited to use with surge suppression devices and can be used for connecting to any type of electrical or non-electrical cable, wire, line, or the like, or any combination thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a surge suppression system for a remote radio head-based wireless communication system. 
         FIG. 2  shows the surge suppression system of  FIG. 1  in more detail. 
         FIG. 3  shows a dome shaped surge suppression unit used in the surge suppression system of  FIG. 1 . 
         FIG. 4  shows the surge suppression unit of  FIG. 3  with a lid removed. 
         FIG. 5  shows a portion of a surge suppression assembly contained in the surge suppression unit of  FIG. 4 . 
         FIG. 6  is a front view of the surge suppression unit of  FIG. 3  with the lid removed. 
         FIG. 7  is a perspective rear view of the surge suppression unit of  FIG. 6 . 
         FIG. 8  is a rear elevation view of the surge suppression unit of  FIG. 7 . 
         FIGS. 9 and 10  show a fiber optic cable tray in more detail. 
         FIG. 11  shows a rack mountable surge suppression unit from  FIG. 1  in more detail. 
         FIG. 12  shows a back end of the surge suppression unit shown in  FIG. 11 . 
         FIG. 13  shows a surge suppression tray for the surge suppression unit shown in  FIG. 11 . 
         FIG. 14  shows how a power terminal assembly in the surge suppression unit is connected to the surge suppression tray. 
         FIG. 15  shows an exploded view of the power terminal assembly. 
         FIG. 16  shows an assembled partial view of the power terminal assembly. 
         FIG. 17  is a rear elevation view of the power terminal assembly. 
         FIG. 18  is a perspective view of the surge suppression tray with a top hood removed. 
         FIG. 19  is an exploded partial view of a surge suppression module located in the surge suppression tray. 
         FIG. 20  is a schematic diagram for the surge suppression modules of  FIG. 19 . 
         FIG. 21  shows an alternative embodiment of a rectangular shaped external surge suppression unit used in the surge suppression system of  FIG. 1 . 
         FIGS. 22 and 23  shows a latching mechanism used with the surge suppression unit of  FIG. 21 . 
         FIG. 24  shows an exploded view of the surge suppression unit in  FIG. 21 . 
         FIG. 25A  shows a perspective view of an enclosure base of the surge suppression unit of  FIG. 21 . 
         FIG. 25B  shows a perspective view of an alternative port based version of the enclosure base of the surge suppression unit of  FIG. 21 . 
         FIG. 26  is a partial view of the interior bottom walls for the surge suppression unit of  FIG. 21   
         FIG. 27  is a sectional elevation view of the bottom walls shown in  FIG. 26 . 
         FIGS. 28A and 28B  are sectional plan views of ports extending through the bottom walls. 
         FIG. 29  is an exploded view of a surge suppression module contained in the surge suppression unit of  FIG. 21 . 
         FIG. 30  is an exploded view of a surge suppression module of  FIG. 29 . 
         FIG. 31  is front sectional view of the surge suppression module. 
         FIG. 32  shows a rack mountable surge suppression unit. 
         FIG. 33  shows a back end of the surge suppression unit shown in  FIG. 32 . 
         FIG. 34  shows a surge suppression tray for the surge suppression unit shown in  FIG. 32 . 
         FIG. 35  shows how a connection panel in the surge suppression unit is connected to the surge suppression tray. 
         FIG. 36  shows an exploded view of the connection panel. 
         FIG. 37  shows an assembled partial view of the connection panel. 
         FIG. 38  is a rear elevation view of the connection panel. 
         FIG. 39  is a perspective view of the surge suppression tray with a top cover removed. 
         FIG. 40  is an isolated view of the surge suppression assembly located in the tray of  FIG. 39 . 
         FIG. 41  is an exploded view of a blind mate inline connector used in the surge suppression assembly of  FIG. 40 . 
         FIG. 42  is side sectional plan view of the blind mate inline connector of  FIG. 41 . 
         FIG. 43  is a side sectional elevation view of the surge suppression unit shown in  FIG. 32   
         FIG. 44  is an exploded perspective view of a surge suppression module located in the surge suppression tray of  FIG. 39 . 
         FIG. 45  is a front sectional view of the suppression module of  FIG. 43 . 
         FIG. 46  is a front perspective view of a modular surge suppression unit. 
         FIG. 47  shows suppression modules removed from the surge suppression unit of  FIG. 46 . 
         FIG. 48  is a rear perspective view of a suppression module in  FIG. 47 . 
         FIG. 49  shows the internal components of the suppression module of  FIG. 48 . 
         FIG. 50A  is front perspective view of the internal components shown in  FIG. 49 . 
         FIG. 50B  is an exploded view for some of the components shown in  FIG. 50A . 
         FIG. 51  is a rear perspective view of the surge suppression unit of  FIG. 46 . 
         FIG. 52  shows a partially disassembled view of a connection panel. 
         FIG. 53  is a side sectional view of the surge suppression unit of  FIG. 46 . 
         FIGS. 54A and 54B  are side sectional views of lugs. 
     
    
    
     DETAILED DESCRIPTION 
     Several preferred examples of the present application will now be described with reference to the accompanying drawings. Various other examples of the invention are also possible and practical. This application may be exemplified in many different forms and should not be construed as being limited to the examples set forth herein. 
       FIG. 1  illustrates one example of a surge suppression system  12  that provides surge suppression for a distributed wireless communication station.  FIG. 2  shows some of the elements of the surge suppression system of  FIG. 1  in more detail. Referring both to  FIGS. 1 and 2 , a building  32  contains computing equipment for a base transceiver station (BTS)  24 . The communication station  24  is connected through fiber optic cables  22  to different radios  18  located on the top of a tower  14 . A Direct Current (DC) power plant  28  is connected through a DC power bus  26  and DC power cables  20  to the different radios  18  on tower  14 . The power bus  26  includes pairs of power cables  230  and  236  that are described in more detail below. The power cables  20  include sets of −48 DC volt power lines, return lines, and associated ground lines that extend out of the building  32  and run up the tower  14  to different associated radios  18 . The radios  18  are connected to associated antennas  16 . 
     This is just one example of a distributed communication system that uses the surge suppression system  12 . It should be understood that the surge suppression system  12  can be used with any communication system or any other electrical system that may require overvoltage protection. 
     A dome shaped surge suppression unit  30  is attached to a support  72  on the top of the tower  14  and is connected to the ends of the power cables  20  proximate to the radios  18  and antennas  16 . In one embodiment, the surge suppression unit  30  is located within 2 meters of the radios  18 . A rack based surge suppression unit  40  is located inside of the building  32  and is connected to the opposite end of the power cables  20  relatively close to the DC power plant  28  and communication station  24 . In one embodiment, the surge suppression unit  40  is located in a rack  25  that also contains the DC power plant  28 . In an alternative embodiment, the surge suppression unit  40  is located in another rack or some other location next to power plant  28 . 
     The radios  18  can be located outside of the building  32  at the bottom of the tower  14 . In this arrangement, the surge suppression unit  40  may still be located in the rack  25 . However, the surge suppression unit  30  may or may not be used for connecting to the opposite ends of the power cables  20  outside of the building  32 . 
     In another communication station configuration, the radios  18  and associated antennas  16  are located at different corners on the roof of a building. Individual surge suppression boxes can be connected to individual power lines  20  close to the different radios  18  on the roof of the building. Each of the boxes may contain surge suppression devices for one or a few power cables and associated radios. In this configuration the surge suppression unit  40  may still be used but surge suppression boxes located on the roof may be configured differently than the dome shaped surge suppression units  30  shown in  FIGS. 1 and 2 . 
     In another configuration the radios  18  and antennas  16  are again located at different corners on a roof of a building. The power cables  20  and fiber optic cables  22  are run into the building and connected to the power plant  28  and communication station  24 , respectively, located within a room of the building. In one embodiment, individual surge suppression boxes are connected to the individual power cables  20  and located next to the associated radios  18  on the roof of the building. A separate fiber/power connector on the top of the building provides a junction between the power lines  20  and fiber optic cables  22  extending inside the building and jumper cables that connect to the radios  18 . 
     In another embodiment where the different radios  18  are located relatively close to each other, the dome shaped surge suppression unit  30  may be used both for containing surge suppression devices and as the junction box for the fiber optic cable jumpers that are distributed out to the radios  18 . In another embodiment, the dome shaped enclosure of unit  30  may only be used as a junction box for the power cables  20  and/or fiber optic cables  22 . The same rack mountable surge suppression unit  40  may be located in the building  32  and may have a same or different surge suppression configuration than the configurations shown in  FIGS. 1 and 2 . 
     External Surge Suppression Unit 
       FIG. 3  shows in more detail the surge suppression unit  30  previously shown in  FIGS. 1 and 2 . A dome shaped plastic lid  60  sits over a base unit  64  that is shown in more detail in  FIGS. 4-6 . A ring clamp  62  provides a weather tight seal between the lid  60  and the base unit  64 . In one embodiment, the entire suppression unit  30  is around 24 inches or 610 millimeters (mm) tall and has a diameter of around 11 inches or around 280 mm. Of course the suppression unit  30  can be other dimensions according to different surge suppression requirements. 
     The top of radio towers may have strict wind load, weight, and space limitations. The aerodynamic cylindrical shape of the dome lid  60  reduces wind load that the suppression unit  30  applies to tower  18  in  FIG. 1 . However, the lid  60  could also have other shapes such as an oval, rounded edge square, triangle, or any other shape that has relatively low wind resistance. One alternative shape is shown below in  FIG. 21 . 
     The lid  60  is vertically elongated to increase the amount of internal space available for containing surge suppression devices and fiber optic connectors. The surge suppression unit  30  also has a relatively small diameter to conserve space and further reduce wind load at the top of tower  14 . In other embodiments where more space is available, the lid  60  may be shorter and have a larger diameter. 
     A mounting bracket  66  includes clamps  68  that attached to the support pole  72 . The clamps  68  hold the mounting bracket  66  perpendicularly out from the side of the pole  72  on the tower  14  in  FIG. 1 . The bracket  66  has a mounting platform  46  with a circular ring shape that forms a circular internal opening  67  ( FIG. 4 ) for receiving the circular base unit  64 . A wiring bracket  70  extends underneath the mounting platform  46 . Tie downs  71  are inserted into holes  73  in the wiring bracket  70  and used for securing the power cables  20  and fiber optic cables  22  that extend down from the bottom of base unit  64 . Alternatively, the mounting bracket  66  could attach to a wall bracket or to a pole that extends up from the top of a roof. The mounting bracket  66  allows the surge suppression unit  30  to be mounted in a vertical elevated position in a large number of different support structures. 
       FIG. 4  is a perspective view of the surge suppression unit  30  with the lid  60  removed. The two clamps  68  of mounting bracket  66  attach through bolts  44  to a back plate  42 . The back plate  42  is aligned vertically and the mounting platform  46  extends horizontally out from the top of back plate  42 . At mentioned above, the ring formed by mounting platform  46  forms a partial circular opening  67  that receives the base unit  64 . Two vertical arms  48  extend down between opposite ends of the mounting platform  46  and opposite ends of the wiring bracket  70 . 
       FIG. 5  is an exploded view showing one of multiple surge suppression assemblies  98  located inside of the surge suppression unit  30 . Referring to  FIGS. 4 and 5 , a wall divider  80  extends vertically up from the middle of base unit  64  and forms two different chambers inside of the lid  60 . Two columns of three surge suppression assemblies  98  are aligned vertically and in parallel next to each other on the power side of the divider wall  80 . 
     Each surge assembly  98  includes a set of three bus bars  122 ,  124  and  128  connected to a pair of vertically stacked surge suppression devices  100 A and  100 B. In one embodiment, the surge suppression devices  100 A and  100 B have a cylindrical disc shaped. One example of the surge suppression devices  100  is the Strikesorb® surge suppression module manufactured by Raycap Corporation, 151 24 Marousi, Athens Greece. However, any type and shape of surge suppression device  100  can be used and the bus bars  122 ,  124 , and  128  can be configured to connect together other types and shapes of surge suppression devices. 
     A ground terminal  134  connects to ground lines  50  in the power cables  20  (see  FIG. 6 ). The ground terminal  134  is electrically coupled to an aluminum ground plate  81  that forms part of the wall divider  80 . The ground plate  81  includes three pairs of tabs  128  that extend up from the bottom of three rectangular openings  52 . The tabs  128  are bent 90 degrees into a horizontal position to form the ground bus bars  128  of the surge suppression assemblies  98 . The ground plate  81  electrically couples together all the ground bus bars  128  and ground cables  50 . This unique grounding configuration reduces the number of ground wires and other components used in the surge suppression unit  30 . 
     The ground bus bars  128  operate as support platforms or shelves for the surge suppression assemblies  98  and allow the different components of the surge suppression assemblies  98  to be easily added or removed from the surge suppression unit  30 . Each bus bar  128  extends horizontally and perpendicularly out from the side of the ground plate  81  and supports a pair of surge suppression devices  100 A and  100 B in a vertical stacked alignment. A connecting member  130  extends out of the bottom end of surge suppression device  100 B and slides into a slot  129  formed in the bus bar  128 . A nut  132  engages with a threaded end of connecting member  130  mechanically and electrically coupling the bottom end of surge suppression device  100 B to the bus bar  128 . 
     A bottom end of surge suppression device  110 A and a top end of surge suppression device  100 B each include holes  139  that receive a connecting member  138 . The connecting member  138  inserts through a hole  135  in return bus bar  124  and mechanically and electrically couple the bottom end of surge suppression device  110 A and the top end of surge suppression device  100 B to return bus bar  124 . A bolt or screw  136  inserts through a hole  141  in bus bar  122  and screws into a hole  137  in the top of the surge suppression device  100 A electrically and mechanically coupling a top end of the surge suppression device  100 A to the bus bar  122 . 
       FIG. 6  is a side elevation view of the suppression unit  30  with the lid  60  removed. A first terminal  120 A on the bus bar  122  is connected to a −48 VDC power line  140 A contained in one of the power cables  20  that connect to the power plant  28  in  FIG. 1 . A second terminal  120 B on bus bar  122  is connected to a second −48 VDC jumper power line  140 B that connects to one of the radios  18  in  FIG. 1 . A first terminal  126 A on the return bus bar  124  connects to a positive or return power line  142 A that is also connected at the other end to the power plant  28  in  FIG. 1 . A second terminal  126 B on return bus bar  124  is connected to a positive/return jumper power line  142 B that connects to the same radio  18  connected to line  140 B. 
     The unique arrangement of the vertically elongated ground plate  81  and the horizontally extending ground bus bars  128  allow multiple pairs of the surge suppression devices  100  to be supported vertically on top of each other in two columns. This compact design allows all of the surge suppression components to be supported on a single side of the divider wall  80  and only extend out from the ground plate  81  little more than the width of the surge suppression devices  100 . In an alternative embodiment, the surge suppression devices  100  may be connected on both sides of divider wall  80 . 
     Pairs of surge suppression devices  100 A and  100 B are readily accessible and easily removed and replaced by simply disconnecting the power lines  140  and  142  from the terminals  120  and  126 , respectively. The bottom surge suppression device  100 B can then be removed from ground bus bar  128 . As mentioned above, the surge suppression devices  100 A and  100 B are aligned vertically one deep on divider wall  80  in two vertically aligned columns. This allows any individual surge suppression device  100 , or any suppression assembly  98 , to be easily replaced without obstruction by any other surge suppression devices  100 . The surge suppression devices  110  and assemblies  98  can also be removed without disrupting operation of any other surge suppression assemblies  98 . This easy accessibility is beneficial when maintenance operations are performed on the top of a tower  14  in  FIG. 1  by technicians with limited mobility. 
     Multiple ports  90  and  91  extend down from the bottom of the base unit  64 . The ports  90  and  91  receive the different power cables  20  and fiber optic cables  22  from the power plant  28 , communication station  24 , and radios  18  shown in  FIG. 1 . In one embodiment, the ports  90  comprise conduits  54  made from a semi-flexible polyvinyl chloride (PVC) pipe. 
     The different lengths of conduit  54  allow a larger number of ports  90  to extend out of the bottom of the circular base unit  64  and also allow relatively easy access by a technician. For example, the variable lengths allow a technician to more easily insert the cables  20  and  22  into the ports  90  and attach caps  56  onto the end of conduits  54 . The elongated ports  90  also provide a long barrier zone between the internal chamber of the suppression unit  30  and the outside environment. 
     Each of the ports  90  has a circular cross sectional shape and contains a gasket  55  that receives the power cables  20  or fiber optic cables  22 . The cables  20  or  22  are inserted along with the gasket  55  into the ports  90  and are then screwed tight inside of the conduits  54  by the caps  56 . One of the ports  90  may receive an alarm monitoring cable  34 . Other ports  91  have an oval cross-section shape and also extend down on opposite sides of the base unit  64  and receive some of the power cables  20  and/or fiber optic cables  22 . 
     The suppression unit  30  has enough ports  90  and  91  to receive six different sets of power cables  20  for powering six different radios  18 . In one embodiment there are two rows of four ports  90  that extend down from base unit  64  on opposite sides of the divider wall  80 . There are also two oval ports  91  that extend down from the base unit  64  from opposite sides of the divider wall  80 . However, any combination of ports  90  and  91  could be provided and any of the unused ports can be covered a waterproof cap  56  until needed. 
       FIGS. 4 and 6  also show monitoring devices  148  coupled between the two bus bars  122  and  124 . The monitoring devices  148  activate a switch when the surge suppression device  100 A is shorted to ground or otherwise fails. The monitoring devices  148  are daisy chained together by cable  34  and attach to alarm terminals  150  at the bottom of the ground plate  81 . Individual LEDs  154  on each of the monitoring devices  148  allow a technician to determine which pairs of surge suppression devices  100 A and  100 B are functional. The wires in the alarm monitoring cable  34  are run from terminal  150  either back to an annunciation device in building  32  in  FIG. 1  or to one of the radios  18  that can then send a signal back over one of the fiber optic cables  22  to a monitoring system. 
       FIG. 7  is a perspective view of the of the suppression unit  30  showing the fiber side of the divider wall  80 .  FIG. 8  shows the fiber side of the divider wall  80  populated with fiber optic cables  22 A and  22 B. Referring to  FIGS. 7 and 8 , the fiber optic cables  22 A from the communication station  24  in  FIG. 1  extend up through one of the ports  90  or  91  and the base unit  64 . The fiber optic cables  22 A wrap partially around one or more of spools  74 . Connectors  112 A at the end of the cables  22 A snap into a first end of adapters  113  that are held in a connector tray  110 . 
     Connectors  112 B on a first end of fiber optic jumper cables  22 B snap into a second end of the adapters  113  that are contained on connector tray  110 . The fiber optic jumper cables  22 B extend from connectors  112 B around one or more of the spools  74 , down through the bottom of base unit  64  and through another port  90  or  91 , and connect to one of the radios  18  in  FIG. 1 . The spools  74  relieve some of the pressure on the fiber optic cables  22  and are also used to take up extra cable length. Retainers  76  hold the fiber optic cables within the fiber side of divider wall  80 . 
       FIGS. 9 and 10  show the connector tray  110  in more detail. The adapters  113  seat into holes  117  located in two different arms  116 A and  116 B of the connector tray  110 . The first arm  116 A of the tray  110  is rigidly attached to the fiber side of the divider wall  80 . The second arm  116 B of the tray  110  rotates about a pin  114  that is rigidly attached to the lateral end of the first arm  116 A. The second arm  116 B can be rotated out in a 90 degree perpendicular relationship from the first arm  116 A. 
     After installation of the fiber optic connectors  112 A and  112 B into opposite ends of the adapters  113 , arm  116 B is rotated about pin  114  into a parallel abutted alignment with arm  116 A. A threaded screw or latch  118  is attached to the end of arm  116 B and inserts and locks into a hole  119  on the lateral end of arm  116 A. 
     The connector tray  110  when in the unlocked 90 degree position in  FIG. 10  allows a technician to more easily install and maintain the fiber optic cables  22 . In the locked position of  FIG. 9 , the arms  116 A and  116 B abut lengthwise against each other to reduce the overall distance the tray  110  extends out from divider wall  80 . In the folded latched position, the tray  110  extends only a small distance out from divider wall  80 . This allows the dome shaped lid  60  in  FIG. 3  to have a smaller diameter. Thus, the surge suppression unit  30  can retain a large number of fiber optic cable connectors  112  in a relatively small tubular footprint. 
     The connector tray  110  is shown with three parallel rows of holes  117  for retaining the adapters  113 . However the tray  110  could have fewer rows or more rows of holes  117  for retaining fewer or more fiber optic cables  22 . The fiber optic cables  22  can be installed in the connector tray  110  during initial installation of the suppression unit  30  on the tower  14  in  FIG. 1  and used later as back-up or when additional radios  18  are installed. 
     Technicians can install the fiber optic jumper cables  22 B and the power jumper cables  140 B and  142 B ( FIG. 6 ) when the suppression unit  30  is initially installed on the tower  14  even before the radios  18  are installed. The technician can then climb up the tower  14  at a later time and attach the previously installed fiber optic jumper cables  22 B and power jumper cables  140 B and  142 B in the suppression unit  30  to different radios  18 . 
     In an alternative embodiment, both sides of the divider wall  80  are configured to support and connect surge suppression assemblies  98  similar to what is shown in  FIG. 6 . In this configuration the surge suppression unit  30  contains up to twelve surge suppression assemblies  98  for attaching to twelve different power cables  20 . In another alternative embodiment, both sides of the divider wall  80  are configured to support and connect fiber optic cables  22  similar to what is shown in  FIG. 8 . In this configuration each side of wall  80  retains a fiber optic connector tray  110 . 
     Rack Mounted Surge Suppression 
       FIG. 11  shows a front perspective view of the rack based surge suppression unit  40  previously shown in  FIG. 1 . The surge suppression unit  40  includes a frame  200  that connects to a rack or support structure  25  such as the same one used for supporting the DC power plant  28  shown in  FIG. 1 . The rear end of the frame  200  supports a power terminal assembly  202  and a front end of the frame  200  supports a surge suppression tray  204 . The front of the surge suppression unit  40  includes a series of light emitting diodes (LEDs)  207  that are activated based on the operational state of surge suppression devices contained in the tray  204 . 
     Mounting brackets  224  attach at the front, back, or middle sides of the frame  200  and attach at the rack or other support structure  25 . For example, a first set of brackets  224  may be used at a first location for a 19 inch rack and a second different set of brackets  224  may be used at a second location for a 23 inch rack. 
     The surge suppression tray  204  has the advantage of having a conventional Rack Unit (RU) form factor that in one embodiment is a 2RU enclosure  209  that can fit into a 19 inch or 23 inch rack configuration. This allows the surge suppression unit  40  to be mounted in the same rack  25  that holds the electronic circuitry for the power plant  28  and/or holds the telecommunication circuitry for the BTS  24  shown in  FIG. 1 . This allows the surge suppression unit  40  to be connected closer to the power plant  28  and telecommunication circuitry  24 . The surge suppression unit  40  can be mounted onto any other rack or other structure that may be housed in the building  32  shown in  FIG. 1 , uses minimal space, and does not require a special mounting structure or rack. 
       FIG. 12  is a perspective view of the frame  200  and power terminal assembly  202 . The frame  200  includes side walls  218  that are connected together at a back end by a back wall  208 . Bottom ends of walls  208  and  218  extend horizontally inward forming a ledge  229  that supports the tray  204  in  FIG. 11 . The back wall  208  includes openings for receiving connectors  226  and  228  that extend out from the power terminal assembly  202 . 
       FIG. 13  is a perspective isolated view of the surge suppression tray  204 . The tray  204  contains surge suppression modules  260  ( FIG. 18 ) that provide surge suppression for the electrical equipment located in the structure  32  in  FIG. 1 . The tray  204  has a rectangular shaped enclosure  209  that slides into, and is supported by, the frame  200  in  FIG. 12 . 
       FIG. 14  is a partial exploded perspective rear view of the rack mountable surge suppression unit  40 . The tray  204  is shown detached in a spaced apart position with respect to the power terminal assembly  202 . In an operational position, the back of tray  204  is slid back against the power terminal assembly  202 . The blind mate connectors  206  and  246  on the back end of tray  204  slidingly insert into mating connectors  226  and  228  in  FIG. 12 , respectively that extend out of the front end of power terminal assembly  202 . 
     The power terminal assembly  202  provides a common in-line connectivity point for the surge suppression modules  260  contained in the tray  204 . This unique in-line connectivity also allows the tray  204  and internal surge suppression devices to be detached from power lines  20  while the power lines are energized without disrupting operation of the radios  18  in  FIG. 1  (hot swappable). Multiple surge suppression units can be removed, replaced, and reattached from the power lines  20  all at the same time simply by connecting or disconnecting tray  204  to or from power terminal assembly  202 . 
       FIG. 15  is an exploded perspective view of the power terminal assembly  202 . A housing  210  receives upper and lower connector strips  212  that are shown in more detail below. Terminals  213  extend out from a back end of the connector strips  212 . Pairs of upper and immediately lower terminals  213 A,  213 B and  213 C,  213 D are shorted together. Insulator blocks  214  include walls  215  that align between the vertical pairs of terminals  213 . 
     Connector rods  217  connect the terminal pairs  213 A,  213 B and  213 C,  213 D to threaded pins or screws  216  that extend out of a circuit board  211 . Etched conductors  220  connect the pins or screws  216  to contact holes  222  that extend through the circuit board  211 . The contact holes  222  receive and connect to pins or sockets  223  contained in the connectors  226  and  228  that extend out the back wall  208  of frame  200 . Ground rods  219  are attached at one end to a ground plane of the circuit board  211 , extend through the insulator blocks  214 , and connect to a ground terminal  221 . Alarm socket  205  connects to monitoring circuits  280  shown below and extends out the back face of housing  210 . 
       FIG. 16  shows a partial assembled view of the power terminal assembly  202 . The ground rods  219  provide a ground connection from ground terminal  221  to the ground plane on the circuit board  211 . The connector rods  217  provide separate power connections from different pairs of shorted terminals  213 A,  213 B and  213 C,  213 D to different pins or screws  216  on the circuit board  211 . The etched conductors  220  on the circuit board  211  electrically connect the pins or screws  216  to the contact holes  222 . The contact holes  222  then electrically connect to corresponding sockets or pins  223  in connectors  226  and  228  ( FIG. 15 ). 
       FIG. 17  shows a rear elevation view of the power terminal assembly  202 . A first lower row of terminals  213 A connect to different −48 v power line jumpers  230  connected to the power plant  28  in  FIG. 1 . A second row of terminals  213 B are shorted to immediately lower ten finals  213 A in the first row and connect to one of the −48 v power lines  140 A in power cable  20  that connect to the external surge suppression unit  30  in  FIG. 1 . 
     A third row of terminals  213 C connect to the different −48 v power return jumper lines  236  that connect to the power plant  28  shown in  FIG. 1 . A fourth row of terminals  213 D are shorted to the immediately lower terminal  213 C in the third row. The terminals  213 D connect to associated −48 v return/positive power lines  142 A in one of the power cables  20  that connect to the surge suppression unit  30  in  FIG. 1 . 
     Each lower row of terminals  213 A,  213 B, and  213 C is set back from the immediately upper row. This allows a relatively large number of power terminals  213  to extend out the back end of the relatively short height of a 2RU frame  200 . 
     Each separate vertical column of terminals  213 A,  213 B,  213 C, and  213 D is associated with the power cable  20  connected to a different radio  18  in  FIG. 1 . There are 12 terminal sets  213 A-D that extend out the back of the terminal assembly  202  that can each connect to a different power cable  20  for powering a different one of the radios  18 . For example, the first terminal set  213 A- 213 D on the far left may be associated with a first power cable  20  that is connected to a first radio  18 . 
     For effective surge suppression protection, surge suppression devices may be located relatively close to the protected electrical circuitry. The rack mountable power terminal assembly  202  provides a common connection location for the surge suppression devices to connect to different power lines and allows surge suppression devices to be closely mounted on the same rack  25  in  FIG. 11  that contains DC power plant  28  and/or communication station  24 . As also explained above, detachably connecting the tray  204  in  FIG. 13  to the power terminal assembly  202  also allows the surge suppression modules in the tray  204  to be more easily connected and disconnected from different power lines. 
     The terminal assembly  202  provides unique “in-line” connectivity between the power lines  140 A,  142 A,  230 , and  236  and the surge suppression modules in tray  204 . The power lines  230  and  236  come into the terminal assembly  202  from the DC power plant  28 . The power lines  140 A and  142 A go out from the terminal assembly  202  through the power cables  20  to the radios  18 . This allows the surge suppression devices in tray  204  to receive power from the power lines  230  and  236  before the power is directed out through power lines  140 A and  142 A to the radios  18 . This in-line feature prevents having to use “T” wiring configurations that are separately run from the power cables to the surge suppression devices. The in-line feature provides controlled, consistent, repeatable, and relatively close connectivity between the surge suppression devices in tray  204  and the DC power supply  28 . 
       FIG. 18  shows a front perspective view of the rack mountable tray  204  with a top hood removed. A bottom floor  252  holds two surge suppression modules  260  alternatively referred to as “six packs.” The two surge suppression modules  260  each include three pairs of surge suppression devices  250 A and  250 B. In other configurations each module  260  could have more or fewer than three pairs of surge suppression devices  250 . In one embodiment, the surge suppression devices  250  are the same as the surge suppression devices  100  used in the surge suppression unit  30  described above. However, other types of surge suppression devices can also be used. 
     The modules  260  are screwed down to the bottom floor  252  of tray  204 . A first cable  266  has a first end connected to a terminal  264  and a second end that includes a pin or socket  254 A that snaps into one of the connectors  206  that extend out the back of tray  204 . A second cable  268  is connected at a first end to a terminal  262  and connected at a second end to a pin or socket  254 B that inserts into another one of the connectors  206  that extend out the back of tray  204 . The terminal  262  connects to a bus bar  274  that has a first portion that extends over a top end of surge suppression device  250 B, a second portion that extends vertically up between surge suppression devices  250 A and  250 B, and a third section that connects to a bottom side of surge suppression device  250 A. 
     Similar cables  266  and  268  are connected to the other pairs of surge suppression devices  250 A and  250 B that are contained within the same suppression module  260 . A first end of a ground cable  288  connects to a ground bus bar  276 . A second end of ground cable  288  includes a socket or pin  254 C that snaps into the push connector  246  that extends out of the back end of the tray  204 . 
     The blind mate in-line push connectors  206  extend out of a back end of the tray  204  and the pins or sockets  254  insert into or receive the blind mate in-line push connectors  226  that extend out from the back wall of the frame  200  as shown in  FIG. 12 . The blind mate in-line push connector  246  extends out of the back end of the tray  204  and connects with the blind mate in-line connector  228  that extends out the back wall of the frame  200  in  FIG. 12 . The connectors  206  and  246  can be easily modified with additional pins or sockets when additional surge suppression modules  260  are added to tray  204 . Other types of connectors that allow easy attachment and detachment between the power terminal assembly  202  and tray  204  can also be used. 
     Only two surge suppression modules  260  are shown in  FIG. 18 . However the tray  204  can be quickly upgraded to add one or two more additional surge suppression modules  260  and provide surge suppression for an additional three or six power cables  20 . The connectors  206  can receive the cables  266  and  268  for four different surge suppression modules  260 . Each module  260  includes three pairs of surge suppression devices  250 A and  250 B that provide surge suppression for three different power cables. Thus, the tray  204  can provide surge suppression for twelve different power cables  20 . Because the surge suppression devices  250  are configured in modules  260 , six different surge suppression devices  250  (3 different pairs) can be removed or added to the tray  204  at the same time. 
     When the tray  204  is inserted into frame  200 , the connectors  206  and  246  align and mate with the connectors  226  and  228 , respectively, that extend out the back wall of frame  200  ( FIG. 12 ). Thus, all of the surge suppression modules  260  and associated surge suppression devices  250 A and  250 B that are contained in tray  204  are connected to multiple different power lines all at the same time simply by plugging tray  204  into the power terminal assembly  202 . 
     The monitoring circuits  280  are mounted between a bus bar  272  and bus bar  274  and connect to the top of each pair of surge suppression devices  250 A and  250 B. The monitoring circuits  280  are connected via clips  284  to a panel  282  that contains the LEDs  207  that extend out the front of tray  204  and identify the operational state for different pairs of surge suppression devices  250 A and  250 B. 
     The LEDs  207  on the front face of the tray  204  are activated when the surge suppression modules  260  are in a powered and operational state. Sets of three radios may be associated with a same frequency. Sets of three LEDs  207  can be associated with the three pairs of surge suppression devices connected to the three power cables  20  powering the three radios having the same frequency. Of course other LED and frequency configurations could also be used. 
       FIG. 19  shows an exploded perspective view for one pair of surge suppression devices  250 A and  250 B in one of the surge suppression modules  260 . The first bus bar  272  connects terminal  264  and one of the −48 v power lines  266  to the top end of surge suppression device  250 A. The z-shaped second bus bar  274  connects horizontally to the bottom end of surge suppression device  250 A, extends vertically up between surge suppression devices  250 A and  250 B, and then extends and connects horizontally to a top end of surge suppression device  250 B. The second bus bar  274  also connects to one of the return power lines  268  in  FIG. 18  through terminal  262 . The ground bus bar  276  is connected to the bottom end of surge suppression device  250 B and mechanically holds together the three pairs of surge suppression devices in the surge suppression module  260 . A mounting bar  278  attaches to the bottom of bus bar  274  and also holds the three pairs of surge suppression devices  250  in the module  260  together. 
       FIG. 20  is a schematic diagram that shows in more detail how the different components in the surge suppression unit  40  are connected together.  FIG. 20  shows surge suppression circuitry and mechanical connections for one pair of surge suppression devices for connecting to one power cable  20 . However, any number of surge suppression devices  250  and corresponding surge suppression circuits similar to that shown in  FIG. 20  can be contained in tray  204 . 
     The power lines  230  and  140 A connect to the terminals  213 A and  213 B, respectively. As mentioned above, the two terminals  213 A and  213 B are shorted together. A connector rod  217 A connects a back end of the terminal pair  213 A and  213 B to a pin or socket in one of the connectors  226  that extends out from the back wall of frame  200 . The power lines  236  and  142 A connect to terminals  213 C and  213 D, respectively. A second connector rod  217 B connects the back of the terminals  213 C and  213 D to another socket or pin in one of the connectors  226 . 
     A first end of the surge suppression device  250 A connects to the −48 v power line from connector rod  217 A. A second end of surge suppression device  250 A connects to a first end of the second surge suppression device  250 B, the return voltage from connector rod  217 B, and one end of a relay  240 . A second end of suppression device  250 B connects to ground via the connectors  246  and  228 . A second end of the relay  240  connects back to the −48 voltage line through one of the LEDs  207  and a rectifier  242 . The relay  240  includes a switch  241  in a first state. The LED  207  is activated when the circuit is powered by the power lines and the surge suppression device  250 A is in a normal open operating state. The relay switch  241  is daisy chained with the relays from the other surge suppression monitoring circuits  280  connected to other surge suppression circuits. The relay  240 , switch  241 , and other alarm circuitry  207  and  242  are located on the alarm board  280  in  FIG. 18 . 
     When the surge suppression device  250 A fails due to a short-circuit condition or power is removed from the circuit, the relay switch  241  switches to a second state causing connections on alarm socket  205  to open or disconnect a circuit that indicates a failure condition. The surge suppression unit  30  shown above in  FIGS. 1-10  may have similar surge suppression circuitry as shown in  FIG. 20 . However, other electrical circuit configurations could also be used. 
     Alternative Embodiment of External Surge Suppression Unit 
       FIG. 21  shows an alternative embodiment of the external surge suppression unit described above in  FIG. 1 . A surge suppression unit  300  has a relatively flat rectangular profile and can be located at any of the locations described above for surge suppression unit  30 . In one example, the surge suppression unit  300  has a weather resistant enclosure  301  made from a polymeric material, such as plastic or semi-flexible polyvinyl chloride (PVC) material. However, the enclosure  301  may also be made out of metal or any other water resistance rigid or semi-rigid material. 
     Enclosure  301  includes an enclosure cover  304  configured to attach to an enclosure base  302 . The enclosure base  302  includes mounting arms  313  that extend out from a back end and include holes  315  for receiving screws or bolts for securing the enclosure  301  to a wall, tower, or any other support structure. In one embodiment, the mounting arms  313  may be attached to a mounting bracket (not shown) that then mounts to the tower  14  or other support structure  72  shown in  FIG. 1 . 
     Latching mechanisms  306  are located around an outside perimeter of the enclosure  301  and are configured to attach the enclosure base  302  in a watertight compression fit with the enclosure cover  304 . The latching mechanisms  306  allow the enclosure cover  304  to be removed from base  302  without the use of tools. For example, latching mechanisms  306  can be locked or unlocked by hand by a technician. The aerodynamically rounded corners of the enclosure  301  reduce wind load and the relatively flat profile allow attachment in confined areas while also providing a substantial amount of interior area for retaining surge suppression and fiber optic equipment. 
       FIG. 22  shows one of latching mechanisms  306  in an unlocked position and  FIG. 23  shows the latching mechanism  306  in a locked position. Latching mechanism  306  includes a retaining member  312  that extends back away from a front face of the enclosure base  302 . A lever  308  is rotatably attached to a support member  314  formed on the edge of enclosure cover  304 . The support member  314  is integrally formed in the enclosure cover  304  and includes slots for receiving an axle  311  attached to a back end of lever  308 . A wire latch  310  is rotatably attached to the lever  308 . The wire latch  310  is configured to attach around the retaining member  312  and lever  308  is configured to rotate about axle  311  and away from the front face of the enclosure cover  304  and pull the wire latch  310  tight against retaining member  312 . 
     In another embodiment, retaining member  312  may be formed on the front face of the enclosure cover  304  and the lever  308  is pivotally attached to the front face of the enclosure base  302 . As shown below, the latch mechanisms  306  hold the front face of the enclosure cover  304  in compression against the front face of enclosure base  302  insulating an internal compartment of the enclosure  301  from external weather conditions. 
       FIG. 24  shows an exploded view of the surge suppression unit  300 . A first section of an internal compartment  324  of enclosure base  302  includes a left hand section  328  of compartment  324  is set back from a right hand section and configured to retain a printed circuit board  402 . The printed circuit board  402  is attached to clips  406  that connect to surge suppression modules  400 . A terminal strip  408  is connected to a bottom end of circuit board  402  and is configured to connect to power cables. The right hand section of compartment  324  contains a tray  334  configured to retain fiber optical cables. 
     A channel  331  is formed in and extends around a top end and sides of a front face  320  of enclosure base  302 . A gasket  322  inserts into channel  331  and also extends along the top end and sides of front face  320 . Enclosure cover  304  includes a first outer lip  352  and a second inner lip  354  that each extends around a top and sides of a front face  350 . 
     When enclosure cover  304  is attached to enclosure base  302 , the outer lip  352  extends over and around the top and sides of the front face  320  of enclosure base  302  and the inner lip  354  inserts into the channel  331  formed in the front face  320  of enclosure base  302 . Attaching the latches  310  to retaining members  312  and rotating the latch mechanisms  306  into their locked position further moves the inner lip  354  further into channel  331  compressing against gasket  322 . 
     Ports  330  extend longitudinally up through a bottom wall  326  from an exterior side of the enclosure base  302  to an interior side of the enclosure base  302 . The ports  330  form elongated vertical slots  332  in a front face of bottom wall  326  and are configured to receive power cables and/or fiber optic cables. A channel  336  extends horizontally along the front face of bottom wall  326  and through ports  330  and is configured to receive a gasket  340 . The gasket  340  includes holes  342  that align with the ports  330  when the gasket  340  is inserted into channel  336 . Slits  344  extend through a front surface of gasket  340  and into the holes  342 . In one example, ridges  346  extend around an inside circumference of some or all of the holes  342 . The wall  326  while shown at the bottom of enclosure base  302  may alternatively be located on one of the sides or top of enclosure base  302 . 
     The enclosure cover  304  may include a bottom wall  356  configured to abut up against the bottom wall  326  of enclosure base  302  and cover the slots  332 . The bottom wall  356  includes arched retention members  358  that extend through the slots  332  and into ports  330  formed in the bottom wall  326  of enclosure base  302 . A gasket  362  is configured to insert into a channel  360  that extends horizontally along the length of bottom wall  356 . A ridge  364  extends out from a front surface of gasket  362 . The ridge  364  compresses against a front surface of gasket  340  when the enclosure cover  304  is attached to enclosure base  302 . 
       FIG. 25A  shows an isolated view of the enclosure base  302 . The surge suppression module  400  is shown installed on the printed circuit board  402  and tray  334  is shown retaining fiber optic cables  382  and  390 . The gasket  340  is also shown inserted into the channel  336  formed in bottom wall  326 . 
     A cable  376  is inserted laterally from the side through one of slots  332  and through the slits  344  and into one of the holes  342  in gasket  340  and ports  330  in bottom wall  326 . In one example, the port  330  receiving cable  376  may be larger than other ports  330  configured to receive power cables  370  and/or fiber optic cables  392 . In at least one example, cable  376  may contain both power cables  378  and  380  and fiber optic cables  382  connected at a far end to the power plant  28  and BTS  24 , respectively, shown in  FIG. 1 . In other embodiments, the port  330  receiving cable  376  may be the same size as other ports  330  and cable  376  may be the same size as the other cables  370  and/or  392 . In another embodiment, a larger center port  330  may not be formed in bottom wall  326 . 
     The cable  370  is inserted into port  330  and seats snugly into one of the gasket holes  342  aligned with the port  330 . Channels  368  may be formed into and around inside walls of the ports  330  and may be configured to receive ties  398  for wrapping around cables  370 ,  376 , and  392 . The ties  398  secure the cables  370 ,  376 , and  392  into ports  330  and can also serve as strain reliefs that distribute retention force of the enclosure  301  against different locations on the cables  370 ,  376 , and  392 . 
     Power cables  378  and  380  attach to two of the upper terminals  404  on terminal strip  408 . The terminals  404  include screws  373  that secure the power cables within terminal holes. The terminals  404  are connected to the surge suppression modules  400  through etched conductor busses  410  on circuit board  402 . The two immediately lower terminals  404  on terminal strip  408  connect to two jumper power cables  372  and  374  that are contained within cable  370  and connect to a radio  18  on tower  14  as shown in  FIG. 1 . Cable  370  slides laterally from the side through one of slits  344  in gasket  340  and through slot  332  into one of the ports  330  and gasket holes  342  located on the left side of bottom wall  326  in a similar manner as cable  376 . 
     Fiber optic cables  382  in cable  376  include connectors  384  that connect to an adapter  386  that is held in tray  334 . A first far end of the fiber optic cables  382  are attached to the communication station  24  in building  32  of  FIG. 1 . A second near end of the fiber optic cables  382  attach to the connectors  384  that insert into adapter  386 . A first near end of fiber optic jumper cables  390  are attached to connectors  388  that insert into a second end of adapters  386 . A second far end of the fiber optic jumper cables  390  connect to the ratios  18  on the top of tower  14  as shown in  FIG. 1 . The fiber optic jumper cables  390  may wrap partially around bend control supports  394  that extend out from the back wall of enclosure base  302 . 
     Several of the fiber optic jumper cables  390  may be contained within cable  392  that also inserts from the side through one of the slits  344  and slots  332  and into an associated port  330  and gasket hole  342  on the right side of bottom wall  326  in enclosure base  302 . In other embodiments, the ports  330  may be different diameters to receive different sizes of cables  370 ,  376 , and/or  392 . 
     At least in one example, a first set of ports  330  on the left side of bottom wall  326  are used for retaining the power cables  370  and a second set of ports  330  on the right side of bottom wall  326  are used for retaining fiber optic cables  392 . However, the power cables  370  and fiber optic cables  392  may be inserted into any of the ports  330 . In other embodiments, there may be more or fewer ports  330  than shown in  FIG. 25A . In another embodiment, ports  330  may be formed on the sides or top end of enclosure base  302 . 
       FIG. 25B  shows an alternative embodiment of the enclosure base  302 . The upper portion of the enclosure base  302  may be similar to what is shown in  FIG. 25A . However, in this embodiment, port holes  333  extend completely through a bottom wall  335  of enclosure base  302 . Plastic conduit  337  may attach into port holes  333  similar to what was previously shown in  FIG. 6 . 
     Any number and variety of sizes of port holes  333 A- 333 F may extend through bottom wall  335 . At least in one example, a first set of ports  333 A- 333 C on the left side of bottom wall  335  may be used for retaining the power cables  370  shown in  FIG. 25A  and a second set of ports  333 E and  333 F on the right side of bottom wall  335  may be used for retaining fiber optic cables  392  shown in  FIG. 25A . A larger port hole  333 D in the center of bottom wall  335  may be used for retaining the cable  376  that contains power cables  378  and  380  and fiber optic cables  382  previously shown in  FIG. 25A . However, the power cables  370  and fiber optic cables  392  may be inserted into any of the ports  333 . In other embodiments, there may be more or fewer port holes  333  than shown in  FIG. 25B . In another embodiment, ports holes  333  may be formed on the sides or top end of enclosure base  302 . 
       FIG. 26  is a partial cut-away view of the bottom wall  326  of enclosure base  302  and the bottom wall  356  of enclosure cover  304 . As described above in  FIG. 25A , a power cable  370  inserts through a slot  332  formed in bottom wall  326  and laterally into port  330 . The power cable  370  also inserts laterally through the slit  344  and into one of the gasket holes  342 . The ties  398  are wrapped and synched around the power cable  370 . In one example, the ties  398  may be plastic zip ties that automatically lock when synched together. Ties  398  are known and therefore not described in further detail. 
       FIG. 27  is a side-section elevation view of the port  330  retaining power cable  370 . Referring to  FIGS. 26 and 27 , enclosure cover  304  attaches over enclosure base  302  and the front face of bottom wall  356  abuts up against a front face of bottom wall  326 . In the closed position the bottom wall  356  holds the cables  370  snugly inside of port  330 . For example, holes  366  fanned in the front face of bottom wall  356  receive the attaching ends of ties  398  and allow the retention members  358  to extend into ports  330  and press against cable  370 . 
     To further hold the cable  370  inside of port  330  and provide a weather tight seal, the ridge  364  formed in gasket  362  presses against outer flaps  367  of gasket  336  and across slit  344 . In one example, top and bottom ends of the flaps  367  compress back and against the front side of the cable  370  while the ridge  346  extending around the inside surface of gasket hole  342  compresses around cable  370  at a third center location. The multiple contact locations of gasket  336  further increase the number of barrier contact points between the external environmental conditions outside of enclosure  301  and the internal compartment  324  of enclosure  301 . 
       FIG. 28A  is a partial sectional plan view of the port  330  retaining cable  370  showing the enclosure cover  304  detached from enclosure base  302 . The channels  368  extend around interior side walls and into a back wall of the ports  330 . A tunnel  371  extends into the back wall of ports  330  forming a post  375 . The tie  398  is inserted into tunnel  371  and wrapped around post  375 . The tie  398  sits recessed in port  330  and the cable  370  is then inserted into port  330  and the ends of tie  398  synched together. When synched, the tie  398  pulls the cable  370  into port  330  and against a front face of post  375 . 
       FIG. 28B  is a sectional plan view of the port  330  with the enclosure cover  304  attached to enclosure base  302 . The front face  357  of enclosure cover  304  presses up against the front face  327  of enclosure base  302 . The inner lip  354  of enclosure cover  304  inserts into channel  331  and presses against gasket  322 . The tie  398  is shown in a full synched position holding cable  370  against the inside wall and post  375  inside of port  330 . The holes  366  in enclosure cover  304  receive and contain the ends of tie  398  and the retention members  358  extend into ports  330  and press against power cables  370 . 
       FIG. 29  shows an exploded perspective view for one of the surge suppression modules  400 . A bolt  431  couples a bus bar  430 A to a first end of a surge suppression device  100 A. A connection member  138  extends out a second end of surge suppression device  100 A and inserts through a hole in a second bus bar  430 B and into a threaded hole on a first end of a second surge suppression device  100 B. A second end of surge suppression device  100 B includes a connection member  130  that inserts through a hole in a third bus bar  430 C and threadingly engages with a nut  432 . 
     The surge suppression devices  100 A and  100 B may be similar to the surge suppression devices  100  described in  FIG. 4  and/or surge suppression device  250  described in  FIG. 10 . However, other types of surge suppression devices could also be used. The bus bars  430  in one example have a substantially flat rectangular profile and may have oppositely inclining sides at a bottom end forming a wedge. 
     A mounting base  434  has an oval cross-sectional shape and is configured to receive surge suppression devices  100 . Two semi-circular mounting supports  435  have a shape and size similar to the circular outside shape of surge suppression devices  100  allowing the two surge suppression devices  100  can sit or snap into the supports  435 . The mounting base  434  may be made from a polymeric material and may include two clips  440  that extend down from opposite lateral sides. 
     A mounting cap  420  extends over surge suppression devices  100  and connects to mounting base  434 . Cap  420  includes clips  422  that extend down from a front and back side and insert into holes  438  formed on the first and back sides of mounting base  434 . Two clips  424  extend down from the lateral sides of cap  420  and insert into holes  436  formed on the lateral sides of mounting base  434 . 
       FIG. 30  is an exploded perspective view of the surge suppression module  400  with the two surge suppression devices  100 A and  100 B shown attached together. The clips  440  are configured to bend inward and insert into slots  442  in the printed circuit board  402  of  FIG. 30 . The two clips  440  are then released and spring back outward against the slots  442 . The bus bars  430 A- 430 C extend down though a bottom end of mounting base  434  and insert into clips  406 A- 406 C, respectively, extending up from printed circuit board  402 . The cap  420  attaches onto the top of mounting base  434  and covers surge suppression devices  100 A and  100 B. The clips  422  snap into holes  438  in mounting base  434  and clips  424  snap into holes  436  in mounting base  434 . 
       FIG. 31  is a front elevational sectional view of the surge suppression module  400 . The clips  406  are mounted to the printed circuit board  402  with screws  452  and nuts  454 . The clips  406  extend up from the printed circuit board  402  and include opposing arms  450 A and  450 B that receive and hold press against opposite sides of a bottom end of bus bars  430 . 
     The surge suppression devices  100 A and  100 B are inserted into mounting base  434  before, during or after the mounting base  434  is attached to circuit board  402 . The surge suppression devices  100 A and  100 B, and bus bars  430 , insert down into the mounting base  434  until the bottom sides of the surge suppression devices  100 A and  100 B abut against the top of mounting supports  435 . Clips  424  press slightly inward while cap  420  is attached onto the top of mounting base  434 . The bottom ends  436  of clips  424  insert into the holes  436  and spring slightly outward locking the mounting cover  420  to the mounting base  434 . 
     The surge suppression module  400  is plugged into the circuit board  402  by pressing the clips  440  inward and inserting the clips into slots  442  in printed circuit board  402 . While inserting clips  440  into circuit board  402 , the bottom ends of bus bars  430  extend down in-between spring arms  450 A and  450 B pushing the two arms  450  outward. The clips  440  are released and spring outward pressing against an outer side of the slots  442 . Latches  425  on the bottom end of clips  440  sit against a bottom side of the printed circuit board  402  and hold the mounting base  434  to the printed circuit board  402 . 
     The entire surge suppression module  400  can be attached and detected to and from printed circuit board  402  without any tools. For example, to remove surge suppression module  400 , the clips  440  are pressed inward and the bottom ends  425  lifted up and out of slots  442 . The surge suppression devices  100 A and  100 B are lifted upward by supports  435  and the bottom ends of bus bars  430  are similarly lifted up and out from in-between the opposing springs aims  450 A and  450 B of clips  406 . Thus, an operator simply has to squeeze and lift the sides of the mounting base  434  in order to detach the surge suppression module  400  from printed circuit board  402 . 
     Modular Rack Mountable Surge Suppression Unit 
       FIG. 32  shows a front perspective view of an alternative embodiment of a rack based surge suppression unit  500 . The surge suppression unit  500  includes a frame  502  that connects to a rack or support structure. The rear end of the frame  502  supports a power connection panel  504  and a front end of the frame  502  supports a surge suppression tray  506 . The front of the surge suppression unit  500  includes a series of light emitting diodes (LEDs)  510  that are activated based on the operational state of surge suppression devices contained in the tray  506 . Handles  511  on a front side of the tray  506  are used for locking the tray  506  to the mounting frame  502 . 
     Mounting brackets  508  attach at the front, back, or middle sides of the frame  502  and attach to the rack or other support structure  25  shown in  FIG. 2 . For example, a first set of brackets  508  may be used at a first location for a 19 inch rack and a second different set of brackets  508  may be used at a second location for a 23 inch rack. 
     The surge suppression unit  500  has the advantage of having a conventional Rack Unit (RU) form factor that in one embodiment is a 2RU housing  522  that can fit into a 19 inch or 23 inch rack configuration. This allows the surge suppression unit  500  to be mounted in the same rack  25  that holds the electronic circuitry for the power plant  28  and/or holds the telecommunication circuitry for the BTS  24  shown in  FIG. 1 . This also allows the surge suppression unit  500  to be connected closer to the power plant  28  and telecommunication circuitry  24 . The surge suppression unit  500  can be mounted onto any other rack or other structure that may be housed in the building  32  shown in  FIG. 1 , uses less space, and does not require a special mounting structure or rack. 
       FIG. 33  is a perspective front view of the frame  502  and connection panel  504 . The frame  502  includes walls  526  extending up the sides of a floor  530  and a back wall  523  that extends up from a back end of floor  530 . A back panel  528  is located in front of connection panel  504  and includes openings  514  for accessing electrical contacts  516  that are attached to the connection panel  504 . The side walls  526  include slots  520  that engage with latches  512  on the tray  506  that are moved by the handles  511  in  FIG. 32 . 
       FIG. 34  is a perspective view of the surge suppression tray  506 . The tray  506  contains surge suppression modules  400  ( FIG. 44 ) that provide surge suppression for the electrical equipment located in the structure  32  in  FIG. 1 . The tray  506  has a rectangular shaped housing  522  that slides into and is supported by the frame  502  in  FIG. 33 . A cover  524  is attached to a top end of the housing  522 . Latch aims  532  rotate and extend out of openings  531  on the sides of housing  522  in response to rotating handles  511  and engage with the slots  520  on the sides of tray  506 . 
       FIG. 35  is a perspective rear view of the surge suppression unit  500 . The tray  506  is shown detached in a spaced apart position with respect to the power connection panel  504 . The back of tray  506  slides back against the power connection panel  504 . In line blind mate high current connectors  540  extend out the back end of tray  506  and include insulator housings  542  that align and insert into openings  514  ( FIG. 36 ) formed in the back panel  528 . Contacts  544  within the insulator housing  542  engage with power contacts  516  in  FIG. 33  located in the connection panel  504 . The contacts  544  extending from tray  506  may be clips and the associated contacts  516  extending out from the connection panel  504  may be a bus bar that together provide a relatively large contact surface area for handling high surge currents. 
     The connection panel  504  includes Kelvin connectors  534  that connect to power cables coupled to both the power plant  20  and to the radios  18  on tower  14  in  FIG. 1 . A first connector  534 A may be connected to a supply power cable and a second connector  534 B may be connected to a return power cable. A connector  540 A in tray  506  is coupled to Kelvin connector  534 A and a connector  540 B in tray  506  is coupled to Kelvin connector  534 B. A ground cable is coupled to connector  536  and alarm connections  538  are located on a left side of the connection panel  504 . 
     The connection panel  504  provides a common in-line connectivity point for the surge suppression modules  400  contained in the tray  506 . The unique in-line connectivity allows the tray  506  and internal surge suppression modules  400  to be detached from energized power lines without disrupting operation of the radios  18  in  FIG. 1  (hot swappable). Multiple surge suppression modules  400  can be removed, replaced, and plugged into the power lines  20  all at the same time simply by connecting or disconnecting tray  506  to or from connection panel  504 . 
       FIG. 36  shows an exploded perspective view of the power connection panel  504 . A cover  550  extends around the Kelvin connectors  534 . Upper and immediately lower terminals  535 A and  535 B, respectively, extend out from a back end of the Kelvin connectors  534 . An insulator block  552  includes walls that extend out from between the Kelvin connectors  534 . 
     Threaded conductive standoffs  554  include a first threaded end that screws into threaded holes in the Kelvin connectors  534 . A second end of the standoffs  554  insert through holes in an insulating spacer  556  and connect to the power contacts  516 . Screws  558  extend through holes in contacts  516  and engage with threaded holes in the second end of conductive standoffs  554 . The alarm connectors  538  extend through a hole  566  in a back wall  523  of the frame  502 . The ground connector  536  is attached to a ground contact  562  that attaches to an opposite side of back wall  523  via screws  564 . 
     The back end of connection panel  504  inserts through an opening  568  in the back wall  523  of frame  502 . A back panel  528  is shown in a spaced forward position in the frame  502 . After installation, the back panel  528  sits just in front of the contacts  516  and  562  so that openings  514  each align with one of the contacts  516  or  562 . The back panel  528  is aligned such that the insulator housings  542  in  FIG. 35  insert into openings  514  and contacts  544  in insulator housings  542  connect to contacts  516  and  562 . 
       FIG. 37  shows a partial assembled view of the power connection panel  504 . The conductive standoffs  554  provide separate power connections between individual Kelvin connectors  534  and different contacts  516 . Each Kelvin connector  534  includes a top terminal  535 A and an immediately lower bottom terminal  535 B that are each shorted together thru a conductive member  546  that extends between the sides of conductive face plates that retain the terminals  535 A and  535 B. 
     Each upper terminal  535 A is set back from the immediately lower terminal  535 B to allow easier attachment of power cable connectors. Each Kelvin connector  534  is separated from an adjacent Kelvin connector  534  by an outwardly extending wall  553  of the insulator block  552  to reduce the chances of unintended shorting between power cables. In one embodiment, the insulator block  552  is made from a non-conductive polymeric material. 
       FIG. 38  shows a rear elevation view of the power connection panel  504 . A first lower terminal  535 B of Kelvin connector  534 A may be connected to a jumper power cable that connects to the power plant  28  in  FIG. 1 . A second upper terminal  535 A of connector  534 A is shorted to terminal  535 B of Kelvin connector  534 A and connects to a power cable that connects to the external surge suppression unit  30  in  FIG. 1  or surge suppression unit  300  in  FIG. 21 . 
     A first lower terminal  535 B of Kelvin connector  534 B may be connected to a jumper power cable that connects to a return power connection in the power plant  28  in  FIG. 1 . The second terminal  535 A of Kelvin connector  534 B is shorted to lower terminal  535 B of connector  534 B and connects to a return power cable that connectors to the external surge suppression unit  30  in  FIG. 1  or surge suppression unit  300  in  FIG. 21 . 
     Each pair of Kelvin connectors  534 A and  534 B is associated with the power cables for a different radio  18  in  FIG. 1 . There are six sets of two Kelvin connectors  534 A and  534 B that extend out the back of the connection panel  504  that can each connect to a different set of power cables for powering a different radio  18 . For example, the first set of connectors  534 A and  534 B on the far right of connection panel  504  may be associated with a first set of power cables connected to a first radio  18 . Each of the six sets of two Kelvin connectors  534 A and  534 B are also connected to an associated one of the surge suppression modules  400  contained within the tray  506 . 
     The connection panel  504  provides unique “in-line” connectivity between power lines and the surge suppression modules  400  in tray  506 . For effective surge suppression protection, surge suppression devices may be located relatively close to the protected electrical circuitry. The rack mountable power connection panel  504  provides a common connection location for surge suppression devices to connect to different power lines and allows surge suppression modules  400  in  FIG. 39  to be closely mounted on the same rack that contains DC power plant  28  and/or communication station  24 . As also explained above, detachably connecting the tray  506  in  FIG. 34  to the power connection panel  504  allows the surge suppression modules  400  in the tray  506  to be more easily connected and disconnected from multiple power lines without disrupting power to the radios  18 . The power lines come into the connection panel  504  from the DC power plant  28 . 
     The power lines go out from the connection panel  504  through the power cables to the radios  18 . This allows the surge suppression modules  400  in tray  506  to receive power from the power lines before the power is directed out through other power lines to the radios  18 . This in-line feature prevents having to use “T” wiring configurations that are separately run from the power cables to surge suppression devices. The in-line feature provides controlled, consistent, repeatable, and relatively close connectivity between the surge suppression modules  400  in tray  506  and the DC power supply  28 . 
       FIG. 39  shows a front perspective view of the rack mountable tray  506  with a top hood removed. A bottom floor holds a surge suppression assembly  580 . The assembly  580  includes a printed circuit board  581  that retains contacts  582  configured to connect to surge suppression modules  400 . Blind mate connectors  540  are attached to the back wall  560  of the housing  522  and are electrically coupled to the contacts  582  via etched conductor busses on printed circuit board  581 . 
     Each set of contacts  582 A,  582 B, and  582 C are configured to plug into an associated surge suppression module  400 . There are six sets of contacts  582 A,  582 B, and  582 C shown located on circuit board  581  for connecting to six different surge suppression modules  400 . In other configurations, more or fewer surge suppression modules  400  may be plugged into assembly  580 . In one embodiment, the surge suppression modules  400  are the same as the surge suppression modules  400  used in the surge suppression unit  300  described above. However, other types of surge suppression devices can also be used, such as the surge suppression modules  260  shown above in  FIG. 10 . Only two surge suppression modules  400  are shown in  FIG. 39 . However, additional surge suppression modules  400  can be plugged into the other sets of connectors  582  in tray  506  and provide surge suppression for up to six sets of power cables  20 . 
       FIG. 40  is an isolated perspective view of the surge suppression assembly  580 . Flexible bus bars  592  attach at a bottom end to the printed circuit board  581  and attach at a top end to one of the insulator housings  542 . A first etched conductor bus (not shown) on printed circuit board  581  connects a supply contact  582 A to a bus bar  592 A that connects to the Kelvin connector  534 A shown in  FIG. 38 . A second etched conductor bus (not shown) on printed circuit board  581  connects a return contact  582 B to a bus bar  592 B that connects to the Kelvin connector  534 B in  FIG. 38 . A third etched conductor bus (not shown) on printed circuit board  581  connects a ground contact  582 C to a ground bus bar  592 C that connects to the ground connector  536  in  FIG. 38 . Similar etched conductor buses on printed circuit board  581  connect the other sets of three contacts  582  and associated surge suppression modules  400  to associated connectors  540  in suppression assembly  580 . 
     Pairs of slots  584  in printed circuit board  581  receive clips from one of the surge suppression modules  400  in a similar manner as described above in  FIG. 31 . Alarm circuits  590  are connected to the contacts  582  in a similar manner as the monitoring circuits  280  described above in  FIG. 20 . Each monitoring circuit  590  is connected to a two position alarm configuration switch  586  configured to selective connect the monitoring circuit  590  in series with any other activated monitoring circuits  590 . The alarm circuit  590  generates an alarm signal on alarm connections  538  in  FIG. 35  when the surge suppression device  100 A in an associated surge suppression module  400  shorts to ground. The alarm signal is described in more detail above in  FIG. 20 . Each of the LEDs  510  is activated when the associated surge suppression module  400  is in a powered and operational state. 
       FIG. 41  shows an exploded perspective view for one of the power connectors  540  and  FIG. 42  shows a section plan view of a power connector  540 . Each power connector  540  includes two flexible bus bars  592  that support an associated insulator housing  542 . A first end of two attachment aims  596  are soldered to top ends of two bus bars  592  and second 90 degree ends of the arms  596  include holes that align with holes  602  in housing  542 . Two high current spring contacts  544  include holes  604  that align with the holes  602  in housing  542  and the holes in arms  596 . Screws  594  insert through the holes  602  and  604  and threadingly engage with nuts  610  located in contacts  544 . 
     Bottom ends of the flexible bus bars  592  are bent at a ninety degree angle with respect to an upper portion of bus bars  592  and include holes  606  that align with holes in the printed circuit board  581 . Dividers  598  extend perpendicularly out form a front face of housing  542  and the arms  596  press against the sides of the dividers  598 . 
     The housing  542  has tapered walls  600  with oppositely inclining sides that extend out the back wall  560  of tray  506  and insert into the openings  514  formed in the back panel  528  of connection panel  504  (see  FIGS. 36 and 39 ). The walls  600  form two internal cavities  608  that contain contacts  544 . In one example, the housing  542  is made from a polymeric material and operates as an insulator. 
       FIG. 43  is a side section elevation view of the tray  506  connected to the frame  502 . A nut and bolt  612  hold the bus bar  592  to the printed circuit board  581 . Bolts  614  extend through the back wall  560  of tray  506  and engage with nuts  616  attached to the front face of housing  542 . The blind mate in-line push connector  540  extends out of the back wall  560  of the tray  506  and inserts into the openings  514  formed in the back panel  528  of connection panel  504 . The power contacts  516  in connection panel  504  insert in-between the spring contacts  544 . 
     Power cables (not shown) are connected to terminals  535 A and  535 B and connect through standoffs  554  to the contacts  516 . The contacts  516  are coupled to spring contacts  544  that are coupled through bus bars  592  to the conductive busses on printed circuit board  581 . The conducting busses couple the bus bars  592  to the surge suppression units in module  400 . 
     When the tray  506  is inserted into frame  502 , the contacts  544  align and mate with the contacts  516  that extend out the back of connection panel  504 . This allows all of the surge suppression modules  400  contained in tray  506  to be connected to multiple different power lines all at the same time simply by plugging tray  506  into the power connection panel  504 . 
       FIG. 44  shows an exploded perspective view for one of surge suppression modules  400  located in tray  506  and is similar to the surge suppression modules  400  previously shown in  FIG. 29 . A first surge suppression device  100 A is coupled by a bolt  431  at one end to a bus bar  430 A. A connecting member  138  extends out a second end of surge suppression device  100 A and inserts through a hole in a second bus bar  430 B and into a threaded hole on a first side of a second surge suppression device  100 B. A second end of surge suppression device  100 B includes a connecting member  130  that inserts through a hole in a third bus bar  430 C and threadingly engages with a nut  432 . 
     The surge suppression devices  100 A and  100 B may also be similar to the surge suppression devices  100  described in  FIG. 4  and/or surge suppression device  250  described in  FIG. 10 . However, other types of surge suppression devices could also be used. The bus bars  430  in one example have a substantially flat rectangular profile and may have oppositely inclining front and back faces that form a wedge at a bottom end. 
     Mounting base  434  has an oval cross-sectional shape and is configured to receive surge suppression devices  100 A and  100 B. Two semi-circular supports  435  have a shape and size similar to the circular circumference of surge suppression devices  100 . Thus, the two surge suppression devices  100 A and  100 B can sit snugly or snap into the supports  435 . The mounting base  434  may be made from a polymeric material and includes two clips  440  extending down from opposite lateral sides that are configured to insert into slots  584  in the printed circuit board  581 . The two clips  440  can be compressed laterally inward and may springly extend back outward toward an original position. 
     The mounting cap  420  may be made from a polymeric material and extends over surge suppression devices  100  and connects to mounting base  434 . Mounting cover  420  includes clips  422  in a front and back end that insert into holes  438  formed on the front and back sides of mounting base  434 . Two clips  424  extend down from the lateral sides of cover  420  and insert into holes  436  formed on the lateral sides of mounting base  434 . 
       FIG. 45  is a front sectional elevation view of the surge suppression module  400 . The contacts  482  are mounted to the top of printed circuit board  581  with screws  570 . The bus bars  430 A- 430 C extend down from a bottom end of mounting base  434  and insert into contacts  582 A- 582 C, respectively. 
     The clips  440  on the sides of mounting base  434  insert into slots  584  formed in printed circuit board  581 . The clips  440  are both pressed inward and inserted into slots  584  in printed circuit board  581 . The clips  440  are released and spring back outward pressing against an outer side of the slots  584 . Latches  424  on the bottom end of clips  440  sit against a bottom side of the printed circuit board  581  and hold the mounting base  434  to the printed circuit board  581 . 
     The surge suppression devices  100 A and  100 B and bus bars  430  insert down into the mounting base  434  until the bottom sides of the surge suppression devices  100 A and  100 B seat into the mounting supports  435 . The cap  420  is attached over mounting base  434  and clips  422  ( FIG. 30) and 424  press slightly inward until inserting into the holes  438  ( FIG. 30) and 436 , respectively. The clips  422  and  424  then spring slightly outward locking the mounting cover  420  to the mounting base  434 . While the mounting base  434  is being attached to the printed circuit board  581 , the bottom ends of bus bars  430  extend down in-between spring arms  583 A and  583 B of contacts  582  pushing the two arms  583  outward. 
     The surge suppression module  400  can be plugged into and detached from printed circuit board  5814  without any tools. For example, the surge suppression module  400  is removed by pressing the clips  440  inward and lifting the retention members  424  up and out of slots  584 . The surge suppression devices  100 A and  100 B are lifted upward by supports  435  and the bus bars  430  are similarly lifted up and out from in-between the contacts  582 . Thus, an operator simply has to squeeze and lift the sides of the mounting base  434  to detach the surge suppression module  400  from printed circuit board  581 . 
     Insertable Box Surge Suppression Unit 
       FIG. 46  shows a front perspective view of yet another alternative embodiment of a rack based surge suppression unit  700 . Surge suppression unit  700  includes a chassis  702  that connects to a rack or support structure. A back end of chassis  702  attaches to a connection panel  704  and a front end of the chassis  702  receives elongated box-shaped surge suppression modules  706 . Handles  708  are located on a front side of the surge suppression modules  706  and are used for longitudinally inserting and removing surge suppression modules  506  into and from chassis  702 . 
     Mounting brackets  710  attach at the front, back, or middle sides of the chassis  702  and attach to the rack or other support structure  25  previously shown in  FIG. 2 . A first pair of brackets  710  may be used at a first side location for a 19 inch rack and a second different pair of brackets  710  may be used at a second side location for a 23 inch rack. 
     The surge suppression unit  700  has the advantage of having a conventional Rack Unit (RU) form factor that in one embodiment uses a 2RU chassis  702  that can fit into a 19 inch or 23 inch rack configuration. This allows the surge suppression unit  700  to be mounted in the same rack  25  that holds the electronic circuitry for the power plant  28  and/or holds the telecommunication circuitry for the BTS  24  shown in  FIG. 1 . This allows the surge suppression unit  700  to be connected closer to the power plant  28  and telecommunication circuitry  24 . Surge suppression unit  700  can be mounted onto any other rack or other support structure that may be housed in the building  32  shown in  FIG. 1 , uses less space, and does not require a special mounting structure or rack. The box shaped suppression modules  706  can also be quickly and easily removed from chassis  702  for easy access to internal suppression devices. 
       FIG. 47  is a perspective view of surge suppression unit  700  showing one of the suppression modules  706  removed from chassis  702  and another one of suppression modules  706  inserted into chassis  702 . Chassis  702  includes multiple horizontally elongated slots  720  for receiving multiple suppression modules  706 . In one example, the chassis  702  is configured to receive six suppression modules  706 . However, any number of slots  720  and suppression modules  706  may be used by varying a width of chassis  702 . Slots  720  are delineated by tracks  718  that are formed by cutting strips into chassis  702  and bending the strips into an internal cavity of chassis  702 . 
     In one example, suppression module  706  has an elongated rectangular box shape configured to retain surge suppression devices end-to-end and insert horizontally into a front end of the chassis  702 . Surge suppression modules  706  are slide into one of slots  720  in-between associated tracks  718  until a faceplate  722  presses up against a front face of chassis  702 . In the fully inserted position, a back end of the suppression modules  706  connect with connection panel  704  previously shown in  FIG. 46 . Any unused slots  720  can be covered with a blank faceplate  712 . 
     Monitor receptacles  714  are located at a bottom end of each slot  720  and receive monitor plugs  736  that extend from a bottom back side of faceplate  722  (see  FIG. 49 ). Monitor receptacles  714  connect monitor circuitry contained in suppression modules  706  with circuitry located on a monitor card  716 . Monitor card  716  inserts into tracks  724  that form a slot on a lateral end of chassis  702 . 
     Monitor card  716  activates a Light Emitting Diode (LED)  726  whenever a failure is detected in one of suppression modules  706 . For example, whenever suppression module  706  is inserted into chassis  702 , the circuitry in monitor card  716  starts monitoring the operational status of surge suppression devices  100  within the suppression module  706 . Circuitry on monitor card  716  then activates LED  726  whenever one of the surge suppression devices  100  in modules  706  is disabled due to a power surge event. 
     Each individual suppression module  706  includes additional monitor circuitry similar to that shown in  FIG. 20  that is configured to active one of LEDs  728  when an associated pair of surge suppression devices is powered and operational. When the LED  726  on monitor card  716  is activated, an operator can locate the failed surge suppression device by identifying an associated deactivated LED  728  on one of suppression modules  706 . 
       FIG. 48  is a perspective isolated rear view of one of suppression modules  706 . Handle  708  is connected to a front side of faceplate  722  and an elongated rectangular box shaped enclosure  730  extends horizontally out from a back side of faceplate  722 . Clips  734  extend from a back end of suppression module  706  and are configured to receive and compress against blade connectors that extend from the connection panel  704  in  FIG. 46 . A monitor plug  736  extends out from a bottom back side of faceplate  722  and inserts into one of the monitor receptacles  714  shown in  FIG. 47 . 
       FIG. 49  is a rear perspective view for one of suppression modules  706  with enclosure  730  removed.  FIG. 50A  is a front perspective view of the suppression module  706  in  FIG. 49 , and  FIG. 50B  is a partial exploded view of the suppression module in  FIG. 50A . Referring to  FIGS. 49 ,  50 A and  50 B, four suppression devices  100 A- 100 D are suspended horizontally end-to-end out from the back side of faceplate  722 . 
     A first end of a bus bar  742 A is coupled to a first end of suppression device  100 A and a middle portion of bus bar  742 A extends parallel along the sides of the surge suppression devices  100 A- 100 D. A second end of bus bar  742 A is parallel to the first end and is connected to clip  734 A. A first end of bus bar  742 B is coupled between suppression device  100 A and suppression device  100 B, a middle portion of bus bar  742 B extends parallel along the sides of surge suppression devices  100 B- 100 D, and a second end of bus bar  742 B is parallel to the first end and is connected to clip  734 B. 
     A first end  743 A of bus bar  742 C is coupled between suppression device  100 C and suppression device  100 D, a middle portion  743 B of bus bar  742 C extends parallel to the side of suppression device  100 D, and a second end  743 C of bus bar  742 C is parallel to the first end and is connected to clip  734 C.  FIG. 50B  shows the first end  743 A of bus bar  742 C in more detail and the first ends of bus bars  742 A,  742 B, and  742 D have a similar shape. A first end of bus bar  742 D is coupled to a back end of suppression device  100 D, a middle portion of bus bar  742 D is perpendicular to the first end, and a second end of bus bar  742 D is parallel to the first end and is connected to clip  734 D. 
     A first end of ground bus bar  744  is coupled between suppression devices  100 B and  100 C, a middle section of ground bus bar  744  extends parallel to the sides of suppression devices  100 A and  100 B, and a second end of ground bus bar  744  is coupled to the back side of faceplate  722 . 
     Spacers  740  are located between the suppression devices  100  and have a substantially square outside perimeter that inserts into one of slots  738  formed around inside walls of enclosure  730 . In one embodiment, spacers  740  are made of plastic or some other non-conductive material and support the suppression devices  100 A- 100 D within two halves  730 A and  730 B of enclosure  730 . A raised ring  741  is formed on a front side of spacer  740  to receive one end of suppression device  100  and an impression is formed on a back end of spacer  740  to receive the first end  734  of bus bar  742 . 
     Slots  748  are formed on opposite sides of spacers  740  to retain the bus bars  742  and/or  744 . Clips  750  are formed on top ends of spacers  740  to retain monitor wires  749 . Some of monitor wires  749  connect to the LEDs  728  on the front side of faceplate  722  and the monitor circuitry shown in  FIG. 20 . Other monitor wires  749  connect to monitor card  716  shown in  FIG. 47  through monitor plug  736 . 
     Referring specifically to  FIG. 50B , suppression device  100 C is seated in ring  741  on the front side of spacer  740 C and the first end  743 A of bus bar  742 C is seated in the impression formed on the back side of spacer  740 C. A connecting member  745  is inserted through the middle of spacer  740 C and through a hole  747  in first end  743 A. The two suppression devices  100 D and  100 C are all screwed onto opposite ends of connecting member  745  and press together spacer  740 C and bus bar  742 C. As a result, a back end of suppression device  100 C, bus bar  742 C, and a front end of suppression device  100 D are all electrically coupled to each other. 
       FIGS. 51 and 52  are rear perspective views of surge suppression unit  700 . Connection panel  704  includes a plastic housing  752  that attaches to a back end of chassis  702 . A monitor plug  758  is also attached to the back end of chassis  702  for remotely connecting to the monitoring circuitry in monitor card  716  shown in  FIG. 47 . 
     Two rows of lugs  754  attach to housing  752 . Each lug  754  includes a blade connector  776  integrally formed and extending from a front end of a lug body  778 . Two holes  766  extend into a back end of lug body  778  and are configured to receive and electrically connect two power cables  756  with blade connector  776 . For example, power cable  756 A in  FIG. 52  is inserted horizontally into hole  766 A of lug  754 E and power cable  756 B is inserted horizontally into hole  766 B of lug  754 E. Two screws  768  in lug  754 E are configured to secure cables  756 A and  756 B inside of holes  766 A and  766 B, respectively. The two power cables  756 A and  756 B are accordingly electrically connected to blade connector  776  via the conductive body  778  of lug  754 E. 
     Each lug  754  is configured to receive a different power cable or power jumper cable. Each set of two upper and two immediately lower lugs  754  are configured to connect to suppression devices  100  in a same suppression module  706  and provide surge suppression for two different radios  18  in  FIG. 1 . For example, a first hole in lug  754 A in  FIG. 51  may connect to a first power cable connected to a first radio. A second hole in lug  754 A may connect a jumper power cable  756  connected to DC power supply  28  in  FIG. 1 . A first hole in lug  754 B in  FIG. 51  may connect to a first return power cable connected to the first radio and a second hole in lug  754 B may connect a first jumper return power cable connected to DC power supply  28 . 
     A first hole in lug  754 C in  FIG. 51  may connect to a second power cable connected to a second radio. A second hole in lug  754 C may connect a second jumper power cable  756  connected to DC power supply  28  in  FIG. 1 . A first hole in lug  754 D in  FIG. 51  may connect to a second return power cable connected to the second radio and a second hole in lug  754 D may connect a second jumper return power cable that connects to DC power supply  28 . 
     A tray  772  holds a ground strip  760 . A ground shield conductor or ground wire  774  in the cables  756  are inserted into the holes  764  in ground strip  760  and held in place by screws  762 . All of the conductors or wires  774  are grounded through ground strip  760  and conductive tray  772  to a system ground cable  770 . 
       FIG. 53  shows a side sectional partial cut-away view of surge suppression unit  700 . Suppression module  706  is shown fully inserted into chassis  702 . Lugs  754  are connected to housing  752  by screws  780 . Clips  734  are spread apart by blade connectors  776  as suppression module  706  inserts into chassis  702 . In the fully inserted position, clips  734  press against opposite upper and lower sides of blade connectors  776  electrically coupling suppression devices  100  in suppression module  706  with power cables  756  connected to lugs  754 . In the fully inserted position, monitor plug  736  in  FIG. 49  inserts into monitor receptacle  714  connecting some of monitoring wires  749  in suppression module  706  with monitor card  716  in  FIG. 47 . 
       FIGS. 54A and 54B  show side sectional views for one of lugs  754 . A clamping cam  782  is located within lug body  778  and is shown in a raised position in  FIG. 54A . Power cable  756  is inserted into hole  766  below clamping cam  782 . In  FIG. 54B , screw  768  is screwed further into a threaded hole  784 . A front end of screw  768  rotates clamping cam  782  in a counter clockwise downward direction causing a bottom end of clamping cam  782  to press power cable  756  down against a bottom wall of hole  766 . Accordingly, power cable  756  is securely fastened against lug body  778  and a secure electrical connection is established between power cable  756  and blade connector  776 . The horizontal alignment of hole  766 , power cable  756 , and screw  768  allow multiple power cables  756  to be independently inserted and clamped down into lugs  754  within a relatively small vertical surface area. 
     Several preferred examples have been described above with reference to the accompanying drawings and pictures. Various other examples of the invention are also possible and practical. The system may be exemplified in many different forms and should not be construed as being limited to the examples set forth above. 
     The figures listed above illustrate preferred examples of the application and the operation of such examples. In the figures, the size of the boxes is not intended to represent the size of the various physical components. Where the same element appears in multiple figures, the same reference numeral is used to denote the element in all of the figures where it appears. 
     Only those parts of the various units are shown and described which are necessary to convey an understanding of the examples to those skilled in the art. Those parts and elements not shown may be conventional and known in the art. 
     Having described and illustrated the principles of the invention in a preferred embodiment thereof, it should be apparent that the invention may be modified in arrangement and detail without departing from such principles. We claim all modifications and variation coming within the spirit and scope of the following claims.