Abstract:
A sealed electrical enclosure used in hazardous locations for enclosing circuit breakers having a bottom housing and a top housing with a labyrinth seal or joint formed therebetween, the bottom housing adapted to receive one or more circuit breakers, a first metal bus extending from a point internal to the bottom housing through a first end wall to a point external thereto, and a second metal bus extending from a point internal to the bottom housing through a second end wall to a point external to thereto, where the first and second metal buses are adapted to contact first and second electrical terminals of a circuit breaker when placed within the bottom housing, and a first vent positioned on the top housing for dissipating pressure buildup, wherein the top housing is removably secured to the bottom housing to allow for removal and replacement of a circuit breakers within the housing.

Description:
RELATED APPLICATION 
       [0001]    This application is a continuation of prior U.S. patent application Ser. No. 12/283,053, filed on Sep. 9, 2008, which claims priority to Indian Patent Application 1673/MUM/2008 filed Aug. 6, 2008. U.S. patent application Ser. No. 12/283,056 and Indian Patent Application 1673/MUM/2008 are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Application 
         [0003]    This application relates generally to sealed electrical enclosures for use in hazardous locations for a variety of electrical components, such as circuit breakers, motor switches, GFI devices, and photocells. 
         [0004]    2. Description of the Related Art 
         [0005]    Traditionally, in North America, to use circuit breakers in a hazardous (classified) area, standard circuit breakers are placed in a cast metal housing such as aluminum, wherein the cast metal housing is bolted shut. In such an arrangement, the circuit breaker switches may be manipulated through a cast metal door that is bolted to the cast metal housing. In North America, this construction is suitable for Class I Division 1 and Class I Division 2 applications. A drawback of this arrangement is that the cast iron enclosures are heavy and cumbersome. Furthermore, it can be time consuming and laborious to remove the often extensive number of bolts from the cast metal housing to access the circuit breakers within. Thus, replacing circuit breakers using enclosures with this construction can be time consuming and costly. 
         [0006]    Alternatively, in Europe, in accordance with IEC methodology, traditionally each circuit breaker or other electrical device is separately and permanently sealed (often potted in epoxy) to provide a flame proof device. Each flame proof sealed circuit breaker or electrical device is then typically placed in a non-metallic or sheet metal enclosure. Each sealed circuit breaker typically has a handle or switch that extends through a door of the non-metallic or sheet metal enclosure to allow for manipulation of the handle or switch. In the event that a circuit breaker needs to be replaced, the flame proof circuit breaker is removed, and a replacement flame proof circuit breaker installed. A drawback to this methodology is that it is more costly to replace each separately sealed flame proof circuit breakers than it is to replace non-flame proof circuit breakers. 
         [0007]    There has been an increased demand for sealed breakers in North America. Thus, there is a need to provide an electrical enclosure for use in hazardous (classified) locations that can provide for the removal and replacement of circuit breakers or other electrical components from a reusable electrical enclosure. For purposes of this application the term “hazardous locations” and “hazardous (classified) locations shall mean areas classified by the National Electric Code (NEC), such as NEC Class I, Division 1 areas. 
       SUMMARY 
       [0008]    The present application provides a sealed electrical enclosure for use in hazardous locations for enclosing circuit breakers or other electrical components comprising a bottom housing and a top housing positioned thereabove; a labyrinth seal or joint being formed between the bottom housing and the top housing; the bottom housing adapted to receive a plurality of circuit breakers or other electrical components; and a first metal bus extending from a point internal to the bottom housing through a first end wall to a point external to the bottom housing; and a second metal bus extending from a point internal to the bottom housing through a second end wall to a point external to the bottom housing; where the first metal bus and the second metal bus are adapted to contact first and second electrical terminals of a first circuit breaker placed within the bottom housing; and a first actuating mechanism positioned on the top housing adapted for manipulating one or more switches of circuit breakers or electrical components positioned within the bottom housing; and a first vent positioned on the top housing for dissipating heat or pressure buildup within the housing; and wherein the top housing is removably secured to the bottom housing to allow for removal and replacement of circuit breakers or other electrical components within the housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Exemplary embodiments of the invention are described herein with reference to the drawings, in which: 
           [0010]      FIG. 1  is a perspective view of an embodiment of a sealed electrical enclosure; 
           [0011]      FIG. 2  is a perspective view of an embodiment of the sealed electrical enclosure of  FIG. 1  adapted for operation externally from an electrical panel box; 
           [0012]      FIG. 3  is a top view of the sealed electrical enclosure of  FIG. 2 ; 
           [0013]      FIG. 4  is a perspective cut-away view of the sealed electrical enclosure of  FIG. 1 ; 
           [0014]      FIG. 5  is a sectional view of the sealed electrical enclosure of  FIG. 1 ; 
           [0015]      FIG. 6  is an exploded view of a sealed electrical enclosure; 
           [0016]      FIG. 7  is a top perspective view of the bottom housing of the sealed electrical enclosure of  FIG. 1 ; 
           [0017]      FIG. 8  is a close up view of a portion of the bottom housing of  FIG. 7 ; 
           [0018]      FIG. 9  is a top perspective view of the top housing of the sealed electrical enclosure of  FIG. 1 ; 
           [0019]      FIG. 10  is a partial cut-away view of a sealed electrical enclosure; 
           [0020]      FIG. 11  is a cut-away view of a portion of the actuating mechanism of the sealed electrical enclosure of  FIG. 1 ; 
           [0021]      FIG. 12  is a perspective view of a sealed electrical enclosure; 
           [0022]      FIG. 13  is a perspective view of two sealed electrical enclosures positioned within an electrical panel box; 
           [0023]      FIG. 14  is a perspective view of four sealed electrical enclosures positioned within an electrical panel box; 
           [0024]      FIG. 15  is a perspective view of various circuit breakers that may be positioned within the sealed electrical enclosure of  FIG. 1 ; 
           [0025]      FIG. 16  is a perspective view of various types of circuit breakers that may be positioned within the sealed electrical enclosure of  FIG. 1 ; and 
           [0026]      FIG. 17  is a perspective view of four sealed electrical enclosures positioned on an electrical panel. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Referring to  FIG. 1 , a perspective view of sealed electrical enclosure  10  is shown having bottom housing  12  and top housing  14 , with top housing  14  being removably secured to bottom housing  12  using bolts  22 . Of course, it is not required to use bolts, but any other suitable means of removably securing top housing  14  to bottom housing  12  could be used such as clips, screws, clamps, latches, etc. Preferably bottom housing  12  and top housing  14  are comprised of hard non-conductive material such as a plastic or composite material, most preferably Solvay IXEF 1022 or Ryton R-4. 
         [0028]    Sealed electrical enclosure  10  further includes an actuating mechanism  20  that allows for the manipulation of the switches of circuit breakers or other electrical components positioned within the enclosure  10 . The actuating mechanism  20  provides for linear actuation, although rotary actuation could be used as well. Enclosure  10  may be used to house various types of circuit breakers and other electrical components such as circuit interrupters, motor switches, GFI devices, and photocells to name a few. Further, enclosure  10  may be used to house both IEC and NEC approved products. 
         [0029]    As shown in  FIG. 1 , electrical buses  30 ,  32 , and  34  extend from a point within the enclosure  10  through a first sidewall  40  to a point external to the enclosure  10  as shown. In this manner, circuit breakers or other electrical products may be positioned entirely within enclosure  10  and electrically connected to electrical terminals in an electrical panel box (not shown). Using the configuration shown, sealed enclosure  10  provides for a flame proof housing for use in Class I, Division 2 applications, and in hazardous locations or areas classified by divisions or zones such as Class I, Zone 1. 
         [0030]    With the configuration of sealed electrical enclosure  10 , by removing bolts  22 , top housing  14  may be removed from bottom housing  12 . As a result, the circuit breakers or other electrical products positioned within the enclosure  10  may be removed and replaced, while allowing sealed electrical enclosure  10  to be reused. 
         [0031]      FIG. 2  discloses sealed electrical enclosure  10 , with external actuating mechanism  20  further including knobs or extensions  50  that allow the enclosure  10  to be positioned within an electrical panel box (not shown), and still allow for the actuating mechanism to manipulate the switch of a circuit breaker or other electrical device positioned within enclosure  10 . 
         [0032]      FIG. 3  is a top view of the enclosure  10  shown in  FIG. 2  showing another view of knobs or extensions  50  positioned on top housing  14 . 
         [0033]      FIG. 4  shows a sectional, perspective view of sealed electrical enclosure  10  with actuating mechanism  20  on top housing  14  including a slidable rigid rod  60  as well as a switch manipulator  70  attached thereto for manipulating switch  74  of a circuit breaker or other electrical device. 
         [0034]      FIG. 5  shows a side sectional view of enclosure  10  and provides another view of actuating mechanism  20  including slidable rigid rod  60  that may be moved in a slidable manner within top housing  14 , as well as switch manipulator  70  attached thereto for manipulating switch  74 .  FIG. 5  also shows electrical bus  30  extending from a point within bottom housing  12  through a first sidewall  40  of bottom housing  12  to a point external to enclosure  10 . Similarly, electrical bus  31  is shown extending from a point within bottom housing  12  through second sidewall  42  of bottom housing  12  to a point external to enclosure  10 . This configuration having electrical buses  30  and  31  extending through the first and second sidewalls  40  and  42  respectively allows a circuit breaker to be positioned within the enclosure  10  with a first electrical terminal of the circuit breaker contacting bus  30  inside of the bottom housing  12  and a second electrical terminal of the circuit breaker contacting bus  31  inside of the bottom housing  12  and thereby providing an electrical connection via bus  30  and  31  to a point external of enclosure  10  to allow further electrical connection to electric terminals within an electrical panel box. 
         [0035]    This configuration allows for the circuit breakers to be completely enclosed with the enclosure  10 , but provides for electrical connection of the circuit breaker to other electrical terminals external to the box. In this manner, the enclosure  10  provides a flame proof enclosure for use in hazardous (classified) areas with the manipulation of the switch  74  external to the enclosure. With such a design, the circuit breakers within the enclosure  10  do not themselves need to be flame proof and can be more easily removed and replaced simply by removing top housing  14  while allowing sealed enclosure  10  to be reused. 
         [0036]    With respect to  FIGS. 1 and 5 , buses  30 - 35  are preferably positioned within their respective sidewalls by a molding process. One method of molding the buses into the sidewalls is by placing the buses into the mold before the molten plastic fills the mold. 
         [0037]      FIG. 6  shows an exploded view of sealed enclosure  10 . In this embodiment, there are shown three separate actuating mechanisms  20  each using a slidable rigid rod  60  with bolts  22  shown on top housing  14 . It should be noted that while slidable rigid rod  60  is preferably of a round cross-section, it could also have a square, hexagonal, oval or other cross-section. Thus, the term “rod” is not limited to a rod having a round cross-section, but encompasses any other suitable geometry as well. 
         [0038]      FIG. 7  shows a perspective view of bottom housing  12 , showing electrical buses  30 ,  32 , and  34  extending through first sidewall  40  from a point within the bottom housing  12 .  FIG. 7  further shows buses  31 ,  33 , and  35  positioned within bottom housing  12  into (and through) second sidewall  42  to a point external to the enclosure  10 . Bottom housing  12  also includes labyrinth channel  80  that is adapted to receive a corresponding labyrinth extension of the top housing  14  (not shown) to form a labyrinth seal or joint, or flame path. A serrated joint could also be used. Also shown in a bottom wall of bottom housing  12  is a venting plate or vent  82  that allows for pressure and heat to dissipate within the enclosure. Vent  82  is preferably formed of a sintered bronze material. Other materials could be used as the vent material such as stainless steel or aluminum. 
         [0039]      FIG. 8  shows a close up view of a portion of bottom housing  12  more clearly showing labyrinth channel  80 . 
         [0040]      FIG. 9  shows a perspective view of top housing  14  and shows a venting plate or  84  vent positioned on the top thereof. Similar to venting plate  82  shown in  FIG. 7 , vent  84  allows for pressure and heat to dissipate within the enclosure. Vent  84  is also preferably formed of a sintered bronze material. 
         [0041]      FIG. 10  is a partial cut-away view of sealed electrical enclosure  10  showing knobs or extensions  50  positioned on actuating mechanism  20 . In this Figure, switch manipulator  70  is shown connected to slidable rigid rod  60  for manipulating switch  74  of a circuit breaker or other electrical component. 
         [0042]      FIG. 11  shows a close up view of slidable rigid rod  60  that slidably extends through bushing  62  that is threadably connected to actuating mechanism  20 . Preferably, there is a very close tolerance between rod  60  and bushing  62  to eliminate any flame path from within the enclosure  10 . Preferably a 0.002 maximum clearance is used. 
         [0043]      FIG. 12  shows a perspective view of sealed electrical enclosure  10  with bottom housing  12  and top housing  14  and  FIG. 13  shows electrical panel box  90  with two sealed enclosures  10  positioned therein. 
         [0044]      FIG. 14  shows four sealed enclosures  10  alternately positioned within an electrical panel box  94 . 
         [0045]      FIG. 15  shows various circuit breakers or electrical devices that may be positioned within the enclosure  10 . Numeral  110  refers to a one-pole NEC circuit breaker design, while numeral  122  refers to a three-pole NEC circuit breaker design. Numeral  100  references IEC circuit breakers or interrupters that also may be positioned within enclosure  10 . Of course, many other kinds of circuit breakers could be used with this enclosure, including two pole designs. 
         [0046]    The present invention is shown in a particular configuration for illustrative purposes only. The enclosure  10  may have varying geometries to accommodate various sized circuit breakers and electrical components. It is contemplated that the enclosure  10  may be used with all of the F-Series or F-frame circuit breaker skus currently available from Cutler-Hammer, ranging up to 225 amps, and covering 1, 2, and 3 pole versions. It is also contemplated that the enclosure  10  may be used with all of the QC Series circuit breaker skus currently available from Cutler-Hammer, ranging up to 100 amps, and covering 1, 2, and 3 pole versions. With some possible modification to the geometry of the housing, it is contemplated that the present design would be suitable for use for many different types of available or yet to be released circuit breakers. 
         [0047]      FIG. 16  discloses bottom housing  12  along with various circuit breakers  118 ,  128 ,  138 ,  148 ,  168 , and  178  that may be positioned within bottom housing  12 . For example, circuit breaker  118  is of a 3 pole variety having a single switch. When circuit breaker  118  is properly positioned within bottom housing  12 , electrical terminal  124  of the circuit breaker  118  contacts bus  34  within the bottom housing  12 , electrical terminal  122  contacts bus  32  within the bottom housing  12 , and electrical terminal  120  contacts bus  30  within the bottom housing  12 . Similarly, electrical terminal  125  of circuit breaker  118  contacts bus  35  within the bottom housing  12 , electrical terminal  123  contacts bus  33  within the bottom housing  12 , and electrical terminal  121  contacts bus  31  (not shown) within the bottom housing  12 . In this manner, the enclosure  10  may accommodate a 3 pole circuit breaker having a single switch. 
         [0048]      FIG. 16  also discloses that more than one circuit breaker may be accommodated. For example, circuit breakers  128 ,  138 , and  148 , all of a 1 pole one switch variety may all be positioned within the bottom housing  12 . Circuit breaker  148  may be properly positioned within bottom housing  12  so that electrical terminal  134  of the circuit breaker  148  contacts bus  34  within the bottom housing  12  and electrical terminal  135  contacts bus  35  within the bottom housing  12 . Similarly, circuit breaker  138  may be properly positioned within bottom housing  12  next to circuit breaker  148  so that electrical terminal  132  of the circuit breaker  138  contacts bus  32  within the bottom housing  12  and electrical terminal  133  contacts bus  33  within the bottom housing  12 . Additionally, circuit breaker  128  may be properly positioned within bottom housing  12  next to circuit breaker  138  so that electrical terminal  130  of the circuit breaker  128  contacts bus  30  within the bottom housing  12  and electrical terminal  131  contacts bus  31  (not shown) within the bottom housing  12 . In this manner, the enclosure may accommodate three separate circuit breakers, in this case each being of the one pole, one switch variety. 
         [0049]      FIG. 16  further discloses that the sealed enclosure may accommodate circuit breakers of varying types and dimensions. For example, circuit breaker  168 , a single pole single switch type, may be positioned within the bottom housing  12  so that electrical terminal  154  of the circuit breaker  168  contacts bus  34  within the bottom housing  12  and electrical terminal  155  contacts bus  35  within the bottom housing  12 . Additionally, circuit breaker  178 , a 2 pole, single switch type, may be properly positioned within bottom housing  12  next to circuit breaker  168  so that electrical terminal  152  of the circuit breaker  178  contacts bus  32  within the bottom housing  12  and electrical terminal  153  contacts bus  33  within the bottom housing  12 , while electrical terminal  150  contacts bus  30  within the bottom housing  12  and electrical terminal  151  contacts bus  31  (not shown) within the bottom housing  12 . In this manner, the enclosure may accommodate two different circuit breakers of different geometries and design. 
         [0050]    It will be appreciated that the enclosure could be enlarged to house additional circuit breakers and its geometry could be modified to accommodate circuit breakers of varying size. 
         [0051]    The sealed enclosure described herein may be used in hazardous (classified) locations including Class I, Division 2 and Class I, Zone 1 environments, and it is believed that it is arc flash proof as well. 
         [0052]      FIG. 17  discloses four sealed electrical enclosures  10  mounted on an electrical panel  150 . It is contemplated that enclosures  10  may be mounted in suitable electrical panels boxes, including stainless steel, plastic, and thin-wall cast panel boxes. 
         [0053]    While certain features and embodiments of the present application have been described in detail herein, it is to be understood that the application encompasses all modifications and enhancements within the scope and spirit of the following claims.