Abstract:
A circuit breaker enables selective left, right or a combination of both side connection to a power conductor, such as a cable or wire. Side connection eliminates the need for large radius U-bends of the power conductor that is normally required when using top connection circuit breakers. An electrically non-conductive cavity commonly defined by left and right sides of the circuit breaker housing receives the power conductor in a connector such as a lug. The circuit breaker may have a visualization window oriented to observe whether excessive cable is projecting out of the lug, so as to confirm compliance with electrical code over surface spacing requirements. In some embodiments, the circuit breaker lugs are vertically oriented above its front cover surface in a receptacle portion of the housing. The receptacle may be constructed for selective lug orientation in horizontal or vertical positions by the installer.

Description:
CLAIM TO PRIORITY 
     This application claims the benefit of United States provisional patent application entitled “SIDE ENTRY CIRCUIT BREAKER” filed Feb. 19, 2008 and assigned Ser. No. 61/029,589, and also provisional patent application entitled “CIRCUIT BREAKER WITH DETACHABLE RECEPTACLE” filed Jul. 30, 2008 and assigned Ser. No. 61/084,719, both of which are incorporated by reference herein. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     1. Field of the Invention 
     The present invention is directed to circuit breakers for circuit protection and control of electrical distribution systems. It is suitable for application in low voltage alternating current electrical systems commonly employed in residential and commercial structures. 
     2. Description of the Prior Art 
     Circuit breakers are often mounted in electrical enclosures, such as metering stacks. Referring to  FIG. 1 , the metering enclosure  10  is of an exemplary type commonly used in multiple unit occupancy buildings. The enclosure  10  has a plurality of stacked electric meters  12  that are coupled to an electric power grid so that they can provide rate-metered electric power to each corresponding occupancy unit. In  FIG. 1 , each meter is in turn wired to a downstream circuit breaker  14 , often through a metering socket assembly having a pair of male stabs that plug into female biased jaws incorporated into the circuit breaker (not shown). The circuit breaker  14  has a pair of load terminals, often of a terminal lug configuration. Each lug is wired to one or more load wires or cables  16 . Generally circuit breaker load terminals are configured at the top of the circuit breaker  12 , as shown in  FIG. 1 . 
       FIG. 2  shows a prior art two-pole circuit breaker  20  that is sold by Siemens Energy &amp; Automation, Inc. The circuit breaker  20  has a left load lug  22  that employs an allen screw  24  for crimped capture of a load cable. There is also a right lug  26  with corresponding allen screw  28 . Both lugs  22 ,  24  are retained in a molded breaker housing  30  proximal the top side housing wall  32 . The front cover  34  includes windows  36 ,  38  for access to the allen screws  24 ,  28 . 
     Referring back to  FIG. 1 , the load cables  16  are routed from the top of the circuit breaker  12  in a U-shaped bend and down in a meter enclosure gutter. Alternatively, the cables  16  are routed in an upwardly direction in an “S-bend”. The cables  16  thereafter exit the meter enclosure  10 , for further distribution to the building occupancy units. Cable thickness dictates the U-bend or S-bend radius necessary for routing them from the circuit breaker to the gutter. As shown in  FIG. 1 , the cable  16  bend radius dictates minimum vertical spacing S between each meter  12  in the enclosure  10 . It is desirable to minimize the vertical spacing S to maximize the number of meters that are stackable in an enclosure cabinet. Elimination of the need to form U-bends or S-bends in the load cables  16  is a desirable objective. One previous solution to eliminate the need for U-bend or S-bend formation in load cables was fabrication of a circuit breaker having side-access lugs. 
       FIG. 3  is a schematic representation of a left side-access circuit breaker  40  previously sold under the MURRAY® brand model designation 200V. The subject prior art circuit breaker  40  had a left lug  42  with allen screw  44  and a corresponding right lug  46  with allen screw  48 . The circuit breaker housing  50  enabled left side access of load cables  16  along the left side wall  52 . Front cover  54 , along with upstanding internal walls  55  in the housing  50  captured and electrically isolated each respective breaker lug  42 ,  46 . Windows  56 ,  58  enabled access to the allen screws  44 ,  46  for selective clamping of the load cables  16 . 
     Full isolation of each of the lugs by surrounding insulating walls  55  and cover  54  was in compliance with electrical code over surface spacing requirements. For example, if a cable lug were not surrounded by insulating material on all sides with exception of the cable insertion direction, it might be possible to have excess cable protruding through the lug in violation of over surface spacing requirements. As a result of the over surface requirement, a drawback of the prior art breaker design  40  is that the lugs were configured at the factory for only left side load cable access, or in one other variation top access similar to the prior art circuit breaker of  FIG. 2 . If an electrical enclosure installation required right side cable routing rather than left side routing, the only practical recourse was to utilize a top-access circuit breaker. 
     It is desirable for electrical enclosure design an installation flexibility to eliminate the need for U-bend or S-bend cable clearances in applications that require left or right side cable gutter routing, or a combination of both in a single enclosure, while complying with electrical code over spacing requirements. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the invention to configure a circuit breaker that eliminates the need to route cables with U-bends or S-bends and offers the flexibility of either left or right side cable routing, or both in any application, while complying with electrical code over spacing requirements. 
     Independent from the first object of the invention, it is an additional and separate object to provide additional cable routing flexibility to enable load cables to be inserted vertically into the circuit breaker lugs in a plane normal to and above the circuit breaker front cover in applications where it is desirable to route cables in a plane above the circuit breaker. 
     These and other objects are achieved by the circuit breaker of the present invention that enables selective side feed of load cables from either the left or right side or a combination of both. The circuit breaker of the present invention allows an enclosure designer to minimize wiring spacing within electrical enclosures by avoiding the need for complex cable bends, while complying with electrical code over surface spacing requirements. 
     One aspect of the present invention is directed to a circuit breaker having a housing defining a longitudinal axis, having left and right surfaces that are generally aligned with the longitudinal axis. The circuit breaker has an electrically non-conductive cavity commonly defined by the housing left and right surfaces, which is adapted for selective insertion and receipt of a power circuit conductor, such as a wire or cable, within either the left or right housing surface. The circuit breaker has a wiring connector that is retained within the cavity, adapted for retention of the power circuit conductor. 
     Another aspect of the present invention is directed to a circuit breaker having a housing defining a longitudinal axis, having left and right surfaces that are generally aligned with the longitudinal axis. An electrically non-conductive cavity is commonly defined by the housing left and right surfaces, that is adapted for selective insertion and receipt of a power circuit conductor, such as for example a wire or cable, within either the left or right housing surface. A wiring connector is retained within the cavity, adapted for retention of a power circuit conductor. The circuit breaker has an inspection window defined by the housing, such as in the cover. The window is oriented for visual inspection of at least a portion of the wiring connector and any power circuit conductor that is retained by the connector. 
     Yet another aspect of the present invention is directed to a circuit breaker having a housing defining a first longitudinal axis and a receptacle portion having left and right surfaces that are generally aligned with a second longitudinal axis, wherein the respective longitudinal axes are aligned generally normal to each other. An electrically non-conductive cavity is commonly defined by the receptacle left and right surfaces, that is adapted for selective insertion and receipt of a power circuit conductor within either the left or right surface. A wiring connector is retained within the cavity, adapted for retention of a power circuit conductor. 
     There is also another aspect of the present invention that is directed to a circuit breaker having a housing defining a first longitudinal axis and a receptacle having left and right surfaces that are generally aligned with a second longitudinal axis. The receptacle is selectively attachable to the housing in a first orientation with the respective longitudinal axes aligned generally in parallel and in a second orientation with the respective longitudinal axes aligned generally normal to each other. An electrically non-conductive cavity is commonly defined by the receptacle left and right surfaces, that is adapted for selective insertion and receipt of a power circuit conductor, such as a cable or wire, within either the left or right surface. The circuit breaker has a wiring connector that is retained within the cavity, adapted for retention of a power circuit conductor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The teachings of the present invention can be readily understood by considering the following detailed description in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a schematic elevational drawing of a prior art metering stack electrical enclosure; 
         FIG. 2  is a perspective view of a prior art top feed-type circuit breaker; 
         FIG. 3  is a schematic partial front elevational view of a prior art left side feed circuit breaker; 
         FIG. 4  is a top right side perspective view of an embodiment of a circuit breaker of the present invention; 
         FIG. 5  is a top left side perspective view of the circuit breaker of  FIG. 4 ; 
         FIG. 6  is a bottom left perspective view of the circuit breaker of  FIG. 4 ; 
         FIG. 7  is a partial front elevational view of the circuit breaker of  FIG. 4 ; 
         FIGS. 8A and 8B  are fragmentary front plan views of a visualization window embodiment of the circuit breaker of the present invention, showing cable retention through a visualization window feature of the present invention; 
         FIG. 9  is a schematic view of an electrical enclosure showing application of an embodiment of a circuit breaker of the present invention configured for left side connection to power cables routed in a left cable gutter; 
         FIG. 10  is a schematic view similar to  FIG. 9 , showing right side connection to power cables routed in a right cable gutter; 
         FIG. 11  is a perspective exploded view of an another embodiment of the circuit breaker of the present invention having a detachable lug receptacle oriented parallel to the circuit breaker longitudinal axis in a horizontal position; 
         FIG. 12  is a perspective exploded view similar to that of  FIG. 11 , having a detachable lug receptacle oriented normal to the circuit breaker longitudinal axis in a vertical position; 
         FIG. 13  is a perspective view of the receptacle housing of  FIG. 11 ; 
         FIG. 14  is a perspective view of the conductor lugs retained in the receptacle housing of  FIG. 13  when oriented in a horizontal position; 
         FIG. 15  is a perspective view of the receptacle housing of  FIG. 12 ; 
         FIG. 16  is a perspective view of the conductor lugs retained in the receptacle housing of  FIG. 15  when oriented in a vertical position; and 
         FIG. 17  is a perspective view of the receptacle housing of the present invention corresponding to the embodiment of  FIGS. 11 and 12 , showing position of knock-outs for selective orientation and connection of the housing to the circuit breaker. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. 
     DETAILED DESCRIPTION 
     After considering the following description, those skilled in the art will clearly realize that the teachings of my invention can be readily utilized in making and using the circuit breaker of the present invention. 
       FIGS. 1-3 , depicting prior art electrical enclosures and circuit breaker designs have been described in the Background of the Disclosure section, above. The prior art circuit breakers did not offer the design application flexibility to enable left or right side wiring connection or a combination of both. Lugs were permanently oriented to enable only left or top side wiring, among other reasons to comply with electrical code over surface spacing requirements, so that wire or cable conductors were maintained at a minimum distance from other components within the electrical enclosure. 
     An embodiment of the circuit breakers of the present invention that enables selective left or right or combination of both side wiring is shown in  FIGS. 4-6 . Referring generally to those figures, circuit breaker  60  has a wiring connector left lug  62  of conventional design, with an allen screw  64  for selective retention of an electrical conductor, such as a cable or wire  16 . Other types of wiring connectors known in the art can be substituted for lug  62 . The circuit breaker  60  is a two pole or phase device and therefore has a right lug  66  with allen screw  68  for selective retention of another phase wire  16 . The present invention can be utilized in single-pole or multi-pole applications. 
     The circuit breaker  60  has a non-conductive breaker housing including a base portion  70  that defines a left side wall  72 , a right side wall  74  and a top wall  76 . The breaker housing  70  defines respective non-conductive left and right lug channel cavities  78 ,  80  that pass through the right  74  and left  72  side walls. The left lug  62  is captured in the left channel  78  and the right lug  66  is correspondingly captured in the right channel  80 . The electrically isolated, non-conductive channel cavities  78 ,  80  isolate the respective electrical phases from each other and from other components in the vicinity of the breaker lugs  62 ,  66 . An electrical cable or other conductor for each phase may be passed through the respective channel cavity  78 ,  80  from either the left or right side or a combination of both, for capture by the respective lug  62 ,  66 . Thereupon the conductor is restrained in the lug by tightening of the appropriate lug screw  64 ,  68  through the housing front cover  82  respective window  84 ,  86 . 
     Referring now to  FIGS. 7 ,  8 A and  8 B, in an embodiment of the present invention the lug windows  84 ,  86  provide for visual inspection of each lug  62 ,  66  and their respective lug faces (e.g.,  62 A in  FIGS. 8A and 8B ). The windows  84 ,  86  allow an installer to see wire extension  16 A beyond the lug faces  62 A as a way to prevent excess extension of wire into the enclosure interior. This feature is helpful to assure compliance with over surface spacing requirements in electrical codes, such as UL  489 . Section 6.6.6. 
     The housing front cover  82  also provides access to the circuit breaker toggle  83  that selectively opens, closes and resets circuit breaker contacts (not shown). The circuit breaker contacts, internal electrical circuit protection and control apparatus (e.g., toggle mechanism and trip unit) and internal bussing are of any known design and not shown for brevity. The term “housing” is used herein to describe the circuit breaker encasement structure that as shown in this embodiment includes a housing base  70  and housing front cover  82 . It is possible that the base and cover (or any portions thereof, may be constructed as a unified molding. 
     Referring to  FIG. 6 , the breaker housing bottom  87  retains a pair of female biased jaws  88 ,  89  for connection to bus stabs in the electrical enclosure (not shown) and are of known design. Electrical current flows through the jaws and a respective line bus (not shown) for each phase, through the respective closed circuit breaker contacts and in turn to the respective load busses connected to each of the respective left and right lugs  62 ,  66 . 
       FIGS. 9 and 10  show application of the circuit breaker  60  of the present invention in respective left gutter and right gutter configurations. In  FIG. 9  the load cables  16  are inserted in the left side wall  72  of the breaker. Conversely in  FIG. 10  the power conductor cables  16  are inserted in the right side wall  72  of the breaker. In both figures, the ability to insert power cables  16  by a simple L-bend rather than a U-bend shown in a  FIG. 1  prior art configuration enables reduction of the vertical spacing S between the ganged meters  12 . 
       FIGS. 11-17  show another embodiment of circuit breaker  90  of the present invention in which the left and right load lugs  92 ,  96  can be oriented in a horizontal position, generally aligned with the longitudinal axis of the breaker or in a vertical position generally normal to the breaker longitudinal axis. The vertical position enables routing of cables above the circuit breaker top cover. While the specific embodiment in  FIGS. 11-17  shows a circuit breaker with convertible lug orientation to either horizontal or vertical positions, one skilled in the art can appreciate that a circuit breaker can be constructed with the lugs oriented only in a fixed, vertical position. 
     Referring to  FIGS. 11 and 14 , the circuit breaker  90  has many features similar to the circuit breaker  60  of  FIGS. 4-10 , including left lug  92  with allen screw  94 , the right lug  96  with allen screw  98 , breaker housing base  100  and front cover  101 . The housing has a front side  102  that retains a pair of load bus tabs  104 ,  106  that in this exemplary embodiment have threaded bores for receipt of load bus fasteners  108 ,  110 . The load bus tabs  104 ,  106  are oriented in load bus housing channels  112 ,  114 . 
     The circuit breaker  90  has a detachable lug receptacle  116  that is formed with lug receptacle base  118  and lug receptacle cover  120 . As with the circuit breaker housing  102 , the receptacle base  118  and cover  120  may be constructed as separate components, as shown, or integrated in whole or in part. As one skilled in the art can appreciate, all or portions of the housing  110  and receptacle  116  can be formed in a unitary construction, such as by way of example orienting the lugs permanently in a vertical position during manufacture. 
     The lug receptacle  116  may be transposed from a horizontal orientation ( FIG. 12 ) or a vertical orientation ( FIG. 13 ) during factory assembly of the breaker  90  or during field installation. In this manner, a single receptacle design may be used in two different applications, thus eliminating the need to manufacture and inventory separate products for each application. 
     The receptacle  116  forms a left lug channel  122  and a right lug channel  124 , as was described with respect to the circuit breaker  60  embodiment, above. Left and right lug windows  126 ,  128  are shown, having the construction and features of the circuit breaker  60  lug windows  84 ,  86 . 
       FIGS. 13 and 14  show in further detail the receptacle  116  components as configured for horizontal lug orientation. The receptacle base  118  is constructed with load bus attachment openings  129 ,  130  for communication with the housing channels  112 ,  114  and defines holes  132 ,  134  for passage of the load bus fasteners  108 ,  110  previously described. Left and right receptacle busses  136 ,  138  are connected to the respective left  92  and right  96  lugs by a U-shaped tongue in each bus mating with a slot in each lug in a manner known to those skilled in the art. Left and right horizontal threaded blocks  140 ,  142  are constructed as part of each of the respective receptacle busses  136 ,  138  for connection to load bus tabs  104 ,  106  by way of the fasteners  108 ,  110 . Any form of fastener known to those skilled in the art suitable for electrical conductor connectivity in circuit breaker applications may be utilized as a substitute for the threaded fasteners  108 ,  110 . 
       FIGS. 15 and 16  show in further detail the receptacle  116  components as configured for vertical lug orientation. The receptacle base  118  is constructed with load bus attachment openings  144 ,  146  for communication with the housing channels  112 ,  114  and defines holes  148 ,  150  for passage of the load bus fasteners  108 ,  110  previously described. Left and right receptacle busses  136 ,  138  are the same as those utilized in the horizontal lug orientation application and are connected to the respective left  92  and right  96  lugs by a U-shaped tongue in each bus mating with a slot in each lug in a manner known to those skilled in the art. Left and right horizontal threaded blocks  154 ,  156  are disposed on opposite sides of the blocks  140 ,  142  that were utilized for the horizontal lug orientation configuration. The threaded blocks  154 ,  156  are constructed as part of each of the respective receptacle busses  136 ,  138  for connection to load bus tabs  104 ,  106  by way of the fasteners  108 ,  110 . 
       FIG. 17  shows an embodiment of the receptacle base  118  wherein all of the load bus tab  104 ,  106  attachment openings and holes for corresponding fasteners  108 ,  110  are formed as knockouts  129 K,  130 K,  132 K,  134 K for horizontal lug orientation. Similar knockouts for vertical lug orientation are shown as  144 K,  146 K,  148 K and  150 K. In this manner, a field installer can determine whether an application calls for horizontal or vertical lug orientation and thereafter remove the appropriate set of knockouts for the desired application. 
     As can be appreciated by those skilled in the art, the circuit breaker of the present invention affords a designer and installer a flexible application product that can be adapted to meet varying wire routing design constraints. 
     Although various exemplary embodiments which incorporate the teachings of the present invention have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate these teachings. Accordingly it is intended that the scope of the present be defined by the accompanying claims given their broadest interpretation allowable by law, rather than by the exemplary embodiments described above that are intended to help those skilled in the art understand how to make and use the subject invention.