Abstract:
An interlock assembly comprising: an interlock plate comprising at least one slot disposed about a central portion thereof, a first locking tab disposed perpendicular to a first side of the interlock plate, and a second locking tab disposed perpendicular to a second side of the interlock plate; and a base disposed adjacent to a bottom surface of the interlock plate, the base comprising at least one perturbation disposed on a surface of the base opposite to the bottom surface of the interlock plate, such that the perturbation is disposed within the slot of the interlock plate, thereby providing the interlock plate with reciprocating movement in relation to the base.

Description:
BACKGROUND 
   1. Field 
   This disclosure relates to interlock assemblies which can be used to prevent main and branch circuit breaker in a panelboard from being simultaneously in the “ON” position. In particular, the unique interlock assembly is particular with a generator panel or ATS (automatic transfer switch) switch when alternative power sources are used by customer to support critical loads in the event of failure of utility power supply. 
   2. Discussion of the Background Art 
   Mechanical interlocks which interconnect a pair of lever operated switches are well known. In circuit breaker panelboards, one such interlock has been mounted on the cover and has slidably interacted with the operator handles of tandemly (transversely) mounted circuit breakers. However, the interlock function is removed with the cover when servicing the panelboard in this version. Another panelboard has a sliding interlock mounted on a bracket which extends along the longitudinal center line of the panel. The ends of the bracket extend along the sides of the respective circuit breakers and are bolted directly to the panel or to the enclosure. One end of the bracket is offset from the center of the panel to clear a bus bar of the panelboard. A different length bracket is required for each panel accepting a different number of circuit breakers which translates into a different length for the panel. It is also necessary to modify the cover opening for the circuit breakers by notching the opening to receive the bracket at each end of the row of circuit breakers since the bracket extends beyond the side surface of the end circuit breakers. Thus, special covers are provided on panelboards or loadcenters utilizing this version of sliding interlock. The provision of special parts increases the cost of the item, both to manufacture and contractors to stock the different parts. 
   One such conventional interlock assembly is set forth in U.S. Pat. No. 5,393,942 to Reiner et al., which discloses a mechanical interlock for the operator handles of two main circuit breakers mounted in a panelboard or loadcenter. The interlock mounts transversely of the interior panel and therefore is not dependent upon the length of the interior panel. The interlock requires no special modification of any parts of the loadcenter or panelboard, thereby using all standard parts. The interlock attaches to the mounting rails of the interior panel by screw fasteners or the like and therefore can be used to provide a hold-down function for the main circuit breakers, thereby eliminating separate components for this function. The interlock slide may also be provided with padlock hasps whereby the operator handles of one or both of the circuit breakers can be locked in the OFF position by inserting the padlock shackle through the appropriate hasp of the interlock slide. 
   The problems associated with conventional interlock kits which convert panelboards to generator panels are that (1) they require ordering of separate front/shield to suit the interlock assemblies; (2) the interlock assemblies are costly due to intricate design involving large part counts, including auxiliary breaker retainers; and (3) convention interlock assemblies are difficult to install. 
   Additionally, the interlock assembly according to the present disclosure is not movably mounted on a bracket attached to mounting rails transversely of the panelboard. To the contrary, the present disclosure pertains to a novel interlock assembly that mounts directly to the panel deadfront. 
   The interlock assembly according to the present disclosure has the following advantages over conventional interlocks, i.e., (1) it is field installable to convert existing panelboards (loadcenter/meter socket loadcenter) into generator panels to support critical loads in residential applications utilizing alternate power sources, (2) its unique configuration allows for mounting directly over the deadfront/shield of a panelboard, (3) it interacts with breaker handles of main and auxiliary breaker to make sure only one breaker is in the “ON” position, and (4) it allows for both the main and auxiliary breakers to be put in the “OFF” position. 
   The present disclosure also provides many additional advantages, which shall become apparent as described below. 
   SUMMARY 
   The interlock assembly according to the present disclosure comprises a base plate and interlock plate forming an interlock assembly. The interlock plate with slots is joined to the base plate with a set of rivets. The base plate is mounted over the deadfront/shield of a panelboard. A template is typically provided along with the assembly kit to locate mounting holes taking appropriate references within the panelboard. The interlock plate interacts with breaker handles of main and auxiliary breakers to make sure only one breaker is in the “ON” position at a time. However, both the main and auxiliary breakers can be put into the “OFF” position or status. 
   Preferably, the interlock assembly according to the present disclosure is field installable to convert existing panelboards (i.e., loadcenter/meter socket loadcenter) into generator panelboards to support critical loads in residential applications utilizing an alternate power source. 
   Optionally, the interlock assembly may include a molded retainer auxiliary main breaker (i.e., plug-in type breaker) in its position to prevent its accidental removal. Such a retainer is mounted over interior the interior of the panelboard with the help of a faster. 
   An interlock assembly comprising: an interlock plate comprising at least one slot disposed about a central portion thereof, a first locking tab disposed perpendicular to a first side of the interlock plate, and a second locking tab disposed perpendicular to a second side of the interlock plate; and a base disposed adjacent to a bottom surface of the interlock plate, the base comprising at least one perturbation disposed on a surface of the base opposite to the bottom surface of the interlock plate, such that the perturbation is disposed within the slot of the interlock plate, thereby providing the interlock plate with reciprocating movement in relation to the base. 
   On embodiment involves the first locking tab comprises a first stop disposed perpendicular to the interlock plate and the second locking tab comprises a second stop disposed perpendicular to the interlock plate, wherein the first and second stops are facing in opposite directions to one another. In this embodiment the reciprocating movement of the interlock plate is in a direction of the axis between the first and second locking tabs. 
   In yet another embodiment the first locking tab comprises an elongated portion and a first end disposed parallel to and facing toward the interlock plate, and the second locking tab comprises an elongated portion and a second stop disposed parallel to and facing away from the interlock plate, wherein the first and second stops are facing in the same direction as one another. In this embodiment the reciprocating movement of the interlock plate is in a direction perpendicular to the axis between the first and second locking tabs. 
   In still another embodiment the first locking tab comprises an elongated portion and a first end disposed parallel to and facing toward the interlock plate, and the second locking tab comprises an elongated portion and a second stop disposed perpendicular to the interlock plate, wherein the first and second stops are facing in perpendicular directions to one another. The reciprocating movement of the interlock plate is in a direction of the axis between the first and second locking tabs. 
   Another embodiment involves the first locking tab comprises an elongated portion and a first stop disposed perpendicular to the interlock plate and the second locking tab comprises a second stop disposed perpendicular to the interlock plate, wherein the first and second stops are facing in opposite directions to one another. In this embodiment the reciprocating movement of the interlock plate is in a direction perpendicular to the axis between the first and second locking tabs. 
   The present disclosure also includes an interlock assembly comprising: an interlock plate comprising at least one slot disposed about a central portion thereof, a locking tab disposed perpendicular to a first side of the interlock plate; and a base disposed adjacent to a bottom surface of the interlock plate, the base comprising at least one perturbation disposed on a surface of the base opposite to the bottom surface of the interlock plate, such that the perturbation is disposed within the slot of the interlock plate, thereby providing the interlock plate with reciprocating movement in relation to the base. The locking tab comprises a stop disposed parallel to the interlock plate. The reciprocating movement of the interlock plate is parallel to the stop. 
   The present disclosure also includes an electrical panelboard adapted to be supplied from primary and alternative electrical supply sources, the panelboard comprising: a panel; a main circuit breaker comprising at least one main breaker handle; an auxiliary circuit breaker comprising at least one auxiliary breaker handle; and an interlock assembly comprising: an interlock plate comprising at least one slot disposed about a central portion thereof, a first locking tab disposed perpendicular to a first side of the interlock plate and in contact with the main breaker handle, and a second locking tab disposed perpendicular to a second side of the interlock plate and in contact with the auxiliary breaker handle; and a base disposed adjacent to a bottom surface of the interlock plate, the base comprising at least one perturbation disposed on a surface of the base opposite to the bottom surface of the interlock plate, such that the perturbation is disposed within the slot of the interlock plate, thereby providing the interlock plate with reciprocating movement in relation to the base, whereby the main breaker handle will be in the “OFF” position whenever the auxiliary breaker handle is in the “ON” position. 
   The present disclosure also includes an electrical panelboard adapted to be supplied from primary and alternative electrical supply sources, the panelboard comprising: a panel; a main circuit breaker comprising at least one main breaker handle; an auxiliary circuit breaker comprising at least one auxiliary breaker handle; and an interlock assembly comprising: an interlock plate comprising at least one slot disposed about a central portion thereof, a locking tab disposed perpendicular to a first side of the interlock plate; and a base disposed adjacent to a bottom surface of the interlock plate, the base comprising at least one perturbation disposed on a surface of the base opposite to the bottom surface of the interlock plate, such that the perturbation is disposed within the slot of the interlock plate, thereby providing the interlock plate with reciprocating movement in relation to the base, whereby the main breaker handle will be in the “OFF” position whenever the auxiliary breaker handle is in the “ON” position. 
   Further objects, features and advantages of the present disclosure will be understood by reference to the following drawings and detailed description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic representation of an interlock assembly according to the present disclosure for use with an indoor/outdoor main circuit breaker panel, wherein both the main and auxiliary main breakers are in the “OFF” position; 
       FIG. 2  is a schematic representation of the interlock assembly configuration of  FIG. 1 ; 
       FIGS. 3   a - c  is schematic representation of the interlock assembly according to the embodiment of  FIG. 1 , wherein a functional sequence is showing the interlock assembly in three different operational positions; 
       FIG. 4  is a schematic representation of an interlock assembly according to another embodiment of the present disclosure for use with a metersocket loadcenter; 
       FIG. 5  is a schematic representation of the interlock assembly configuration of  FIG. 4 ; 
       FIGS. 6   a - c  is schematic representation of the interlock assembly according to the embodiment of  FIG. 4 , wherein a function sequence is showing the interlock assembly in three different operational positions; 
       FIG. 7  is a schematic representation of an interlock assembly according to another embodiment of the present disclosure for use with a metersocket loadcenter; 
       FIG. 8  is a schematic representation of the interlock assembly configuration of  FIG. 7 ; 
       FIGS. 9   a - c  is schematic representation of the interlock assembly according to the embodiment of  FIG. 7 , wherein a functional sequence is showing the interlock assembly in three different operational positions; 
       FIG. 10  is a schematic representation of an interlock assembly according to another embodiment of the present disclosure for use with a metersocket loadcenter; 
       FIG. 11  is a schematic representation of the interlock assembly configuration of  FIG. 10 ; 
       FIGS. 12   a - c  is schematic representation of the interlock assembly according to the embodiment of  FIG. 10 , wherein a functional sequence is showing the interlock assembly in three different operational positions; 
       FIG. 13  is a schematic representation of an interlock assembly according to another embodiment of the present disclosure for use with a metersocket loadcenter; 
       FIG. 14  is a schematic representation of the interlock assembly configuration of  FIG. 13 ; and 
       FIGS. 15   a - c  is schematic representation of the interlock assembly according to the embodiment of  FIG. 13 , wherein a functional sequence is showing the interlock assembly in three different operational positions. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The present disclosure is best understood by reference to the attached figures, wherein  FIGS. 1 and 2  provide a schematic representation of one embodiment according to the present disclosure suitable for indoor/outdoor main circuit breaker loadcenter.  FIG. 1  depicts main breaker  1 , branch breaker  3  and auxiliary breaker  5 , wherein an interlock plate  7  with slots  8  are disposed over base plate  9  and secured thereto via rivets  11 . Base plate  9  is secured to the front plate of deadfront/shield  13  of the panelboard via bolts  15 . Interlock plate  7  includes oppositely disposed locking tabs  17 ,  18  disposed against breaker handles  19 ,  20 , respectively. According to  FIG. 1  breaker handle  19  of auxiliary main breaker  5  is locked in the “OFF” position or status, whereas breaker handle  20  of main breaker  1  is also locked in the “OFF” position. 
     FIGS. 3   a - c  depicts three position of the interlocking assembly of  FIG. 1 , wherein  FIG. 3   a  locks main breaker handle  20  in the “ON” position and auxiliary main breaker handle  19  in the “OFF” position.  FIG. 3   b  locks breaker handle  20  in the “OFF” position and breaker handle  19  in the “OFF” position.  FIG. 3   c  locks breaker handle  20  in the “OFF” position and breaker handle  19  in the “ON” position. To switch “ON” the auxiliary main breaker  5 , switch “OFF” main breaker  1 , slide interlock plate  7  upwards to lock the position of main breaker handle  20  and switch “ON” auxiliary main breaker  5 . Both the breakers  1 , 5  will not be in the “ON” position at the same time as they are operated individually. Also, both the main and auxiliary breakers,  1 , 5  must be in the “OFF” position before any of the breakers switch to the “ON” position. 
     FIGS. 4 and 5  provide a schematic representation of another embodiment according to the present disclosure suitable for metersocket circuit breakers.  FIG. 4  depicts main breaker  30 , branch breaker  32  and auxiliary breaker  34 , wherein an interlock plate  36  with slots  38  are disposed over base plate  40  and secured thereto via rivets  42 . Base plate  40  is secured to the front plate of deadfront/shield  44  of the panelboard via bolts  46 . Interlock plate  36  includes oppositely disposed locking tabs  48 , 49  disposed against breaker handles  50 , 51 , respectively. Locking tab  48  comprises an elongated neck portion  55 , whereas locking tab  49  has a short neck  56 . In addition, interlock plate  36  include a large centrally disposed mid-section  58  which include at least four (4) slots  42 . According to  FIG. 4  breaker handle  51  of auxiliary main breaker  34  is locked in the “OFF” position or status, whereas breaker handle  50  of main breaker  30  is locked in the “ON” position. 
     FIGS. 6   a - c  depicts three position of the interlocking assembly of  FIG. 4 , wherein  FIG. 6   a  breaker handle  50  in the “ON” position and locks auxiliary main breaker handle  51  in the “OFF” position.  FIG. 6   b  locks breaker handle  50  in the “OFF” position and breaker handle  51  is in the “OFF” position.  FIG. 6   c  locks breaker handle  50  in the “OFF” position and breaker handle  51  in the “ON” position. To switch “ON” the auxiliary main breaker  34 , switch “OFF” main breaker  30 , slide interlock plate  36  leftwards to lock the position of main breaker handle  50  and switch “ON” auxiliary main breaker  34 . Both the breakers  30 , 34  will not be in the “ON” position at the same time as they are operated individually. Also, both the main and auxiliary breakers,  30 , 34  must be in the “OFF” position before any of the breakers switch to the “ON” position. 
     FIGS. 7 and 8  provide a schematic representation of another embodiment according to the present disclosure suitable for metersocket circuit breakers.  FIG. 7  depicts main breaker  60 , branch breaker  62  and auxiliary breaker  64 , wherein an interlock plate  66  with slots  68  are disposed over base plate  70  and secured thereto via rivets  72 . Base plate  70  is secured to the front plate of deadfront/shield  74  of the panelboard via bolts  76 . Interlock plate  66  includes oppositely disposed locking tabs  78 , 79  disposed against breaker handles  80 , 81 , respectively. Locking tab  78  comprises an elongated neck portion  85  and generally C-shaped, and locking tab  79  has a elongated neck portion  86  and is generally L-shaped. In addition, interlock plate  66  include a large centrally disposed mid-section  88  which include at least four (4) slots  72 . According to  FIG. 7  breaker handle  81  of auxiliary main breaker  64  is locked in the “OFF” position or status, whereas breaker handle  80  of main breaker  60  is locked in the “ON” position. 
     FIGS. 9   a - c  depicts three position of the interlocking assembly of  FIG. 7 , wherein  FIG. 9   a  locks breaker handle  80  in the “ON” position and breaker handle  81  in the “OFF” position.  FIG. 9   b  locks breaker handle  80  in the “OFF” position and breaker handle  81  in the “OFF” position.  FIG. 9   c  locks breaker handle  80  in the “OFF” position and breaker handle  81  in the “ON” position. To switch “ON” the auxiliary main breaker  64 , switch “OFF” main breaker  60 , slide interlock plate  66  downward to lock the position of main breaker handle  80  and switch “ON” auxiliary main breaker  64 . Both the breakers  60 , 64  will not be in the “ON” position at the same time as they are operated individually. Also, both the main and auxiliary breakers,  60 , 64  must be in the “OFF” position before any of the breakers switch to the “ON” position. 
     FIGS. 10 and 11  provide a schematic representation of another embodiment according to the present disclosure suitable for metersocket circuit breakers.  FIG. 10  depicts main breaker  90  and auxiliary breaker  94 , wherein an interlock plate  96  with slots  98  are disposed over base plate  100  and secured thereto via rivets  102 . Base plate  100  is secured to the front plate of deadfront/shield  104  of the panelboard via bolts  106 . Interlock plate  96  includes locking tab  108  disposed against breaker handle  110 , respectively. Locking tab  108  comprises are retangularly shaped portion that is disposed perpendicular from interlock plate  96 . According to  FIG. 10  breaker handle  110  of auxiliary main breaker  94  is locked in the “OFF” position or status, whereas breaker handle  117  of main breaker  90  is locked in the “ON” position. 
     FIGS. 12   a - c  depicts three position of the interlocking assembly of  FIG. 10 , wherein  FIG. 12   a  locks breaker handle  117  in the “ON” position and breaker handle  110  in the “OFF” position.  FIG. 12   b  locks breaker handle  117  in the “OFF” position and breaker handle  110  in the “OFF” position.  FIG. 12   c  locks breaker handle  117  in the “OFF” position and breaker handle  110  in the “ON” position. To switch “ON” the auxiliary main breaker  94 , switch “OFF” main breaker  90 , slide interlock plate  96  upwards to lock the position of main breaker handle  117  and switch “ON” auxiliary main breaker  94 . Both the breakers  90 , 94  will not be in the “ON” position at the same time as they are operated individually. Also, both the main and auxiliary breakers,  90 , 94  must be in the “OFF” position before any of the breakers switch to the “ON” position. 
     FIGS. 13 and 14  provide a schematic representation of another embodiment according to the present disclosure suitable for metersocket circuit breakers.  FIG. 13  depicts main breaker  120 , branch breaker  122  and auxiliary breaker  124 , wherein an interlock plate  126  with slots  128  are disposed over base plate  130  and secured thereto via rivets  132 . Base plate  130  is secured to the front plate of deadfront/shield  134  of the panelboard via bolts  136 . Interlock plate  126  includes oppositely disposed locking tabs  138 , 139  disposed against breaker handles  140 , 141 , respectively. Locking tab  138  comprises an elongated neck portion  145  and generally L-shaped, and locking tab  139  has a shortened neck portion  146  and is generally I-shaped. In addition, interlock plate  126  include an elongated centrally disposed mid-section  148  which include at least four (4) slots  128 . According to  FIG. 13  breaker handle  141  of auxiliary main breaker  124  is locked in the “OFF” position or status, whereas breaker handle  140  of main breaker  120  is locked in the “ON” position. 
     FIGS. 15   a - c  depicts three position of the interlocking assembly of  FIG. 13 , wherein  FIG. 15   a  locks breaker handle  140  in the “ON” position and breaker handle  141  in the “OFF” position.  FIG. 15   b  locks breaker handle  140  in the “OFF” position and breaker handle  141  in the “OFF” position.  FIG. 15   c  locks breaker handle  140  in the “OFF” position and breaker handle  141  in the “ON” position. To switch “ON” the auxiliary main breaker  124 , switch “OFF” main breaker  120 , slide interlock plate  126  leftward to lock the position of main breaker handle  140  and switch “ON” auxiliary main breaker  124 . Both the breakers  120 , 124  will not be in the “ON” position at the same time as they are operated individually. Also, both the main and auxiliary breakers,  120 , 124  must be in the “OFF” position before any of the breakers switch to the “ON” position. 
   While we have shown and described several embodiments in accordance with our invention, it is to be clearly understood that the same may be susceptible to numerous changes apparent to one skilled in the art. Therefore, we do not wish to be limited to the details shown and described but intend to show all changes and modifications that come within the scope of the appended claims.