Patent Publication Number: US-9842716-B2

Title: Circuit interrupters and electrical enclosures with rejection features

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The instant application claims priority from U.S. patent application Ser. No. 13/963,359 filed Aug. 9, 2013, the disclosures of which are incorporated herein by reference. 
     BACKGROUND 
     Field 
     The disclosed and claimed concept relates generally to electrical interruption equipment, and more particularly, to circuit interrupters and electrical enclosures which resist installation of a main circuit interrupter having a given current carrying rating from being installed in an electrical enclosure having a current rating less than the given current carrying rating. 
     Related Art 
     Electrical interruption equipment is well known for use in any of a variety of electrical applications in order to protect circuits or portions of circuits from certain predefined conditions. The predefined conditions can include overcurrent conditions, undervoltage conditions, fault conditions, and other conditions. Such electrical interruption equipment can include circuit interrupters such as circuit breakers, vacuum interrupters, and the like, and can further include electrical enclosures such as breaker panels, load centers, switchgear enclosures, and the like within which the circuit interrupters can be installed. 
     In certain applications such as domestic applications and other applications, the electrical interruption equipment may include an electrical enclosure that receives a main current feed and that distributes current to various other smaller circuits. Each such smaller circuit typically is protected by its own circuit interrupter having an appropriate current carrying rating. Such circuit interrupters are often installed in slots on the electrical enclosure and connect with one or more electrical bus bars within the electrical enclosure to provide current to the individual circuits. Such circuit interrupters are typically intended to individually trip in certain predefined circumstances in order to protect the corresponding circuit from any of the aforementioned predefined conditions. 
     The electrical interruption equipment in such an application typically additionally includes a main circuit interrupter that is interposed between the main current feed and the bus bars and is intended to trip and thus interrupt the flow of current to the bus bars if the overall current draw of all of the circuits combined exceeds a given current level and/or in other circumstances. Such a main circuit interrupter typically is selected to have a current carrying rating no greater than the current rating of the electrical enclosure. That is, the current flowing through the bus bars to the individual circuits results in I 2 R heating of the bus bars and other components, and an electrical enclosure thus has a current rating which should not be exceeded. This is in order to avoid possible damage to the electrical interruption equipment and possible injury and/or property destruction. The main circuit interrupter is thus typically selected to have a current carrying rating no greater than the current rating of the electrical enclosure, meaning that the main circuit interrupter will interrupt the current flow to the bus bars if the aggregate current flowing through the individual circuits that are connected with the bus bars reaches the current rating of the electrical enclosure. By way of example, a given electrical enclosure may have a current rating of 200 Amps, and it may have connected therewith various circuits that are protected by circuit interrupters mounted on the electrical enclosure and that may have current carrying ratings such as 15 Amps, 20 Amps, 30 Amps, 50 Amps, and the like depending upon the characteristics of the circuit. The aggregate current capacity of all of the various circuits combined (i.e., by adding together all of the various current carrying ratings of all of the circuit interrupters connected with the individual circuits) often exceeds the current rating of the panel because it is expected that fewer than all of the protected circuits will be simultaneously carrying their maximum current, such as in the way an electrical resistance furnace and an air conditioner would typically never be simultaneously operated even though they may be connected via separate individual circuits interrupters with the same load center. 
     While such electrical interruption equipment has been generally effective for its intended purposes, it has not been without limitation. Many of the circuit interrupters, including the main circuit interrupters and the individual circuit interrupters that are connected therewith, look very similar to one another. Even though the current carrying rating of a given circuit interrupter is typically clearly printed on the circuit interrupter itself, a possibility exists that a circuit interrupter, such as a main circuit interrupter having a current carrying rating that is less than or greater than what was intended to be used, can be connected with a given circuit such as between the main current feed and the bus bars of the electrical enclosure. An erroneous installation of a circuit interrupter having a current carrying rating less than what had been intended does not typically result in a meaningful concern of equipment damage or injury, apart from the fact that it may trip more often than is appropriate. Such frequent tripping might occur because the loads connected with the circuit interrupter may have been designed to draw relatively higher current and to be protected with a circuit interrupter having a greater current carrying rating than the erroneously installed circuit interrupter. However, the erroneous installation of a circuit interrupter having a current carrying rating greater than the protected circuit or the electrical enclosure itself can be problematic because the erroneously installed circuit interrupter does not trip when the current flowing through the connected circuit exceeds that for which it was originally designed. Such a situation can undesirably result in a potential for equipment damage, property destruction, and personal injury. It thus would be desirable to provide electrical interruption equipment that avoids such a possibility. 
     SUMMARY OF THE INVENTION 
     These and other needs are met by an improved set of circuit interrupters and electrical enclosures that are configured to permit an electrical enclosure having a current rating to have connected therewith a circuit interrupter having a current carrying rating no greater than the current rating. However, a current interrupter having a current carrying rating less than the current rating of the electrical enclosure potentially may be connected therewith. Such electrical interruption equipment employs threaded studs on bus bars that are of varying sizes and/or are separated by varying distances in order to resist an electrical enclosure having a current rating from being electrically connected with a circuit interrupter having a current carrying rating greater than the current rating. Alternatively or additionally, the circuit interrupter and/or the electrical enclosure may have interference elements that physically interfere with the mounting and/or the electrical connection of a circuit interrupter having a current carrying rating with an electrical enclosure having a current rating less than the current carrying rating. 
     Accordingly, an aspect of the disclosed and claimed concept is to provide one or more circuit interrupters and/or to provide one or more electrical enclosures whereby a given circuit interrupter can be electrically connected with an electrical enclosure only if the current carrying rating of the circuit interrupter is no greater than the current rating of the electrical enclosure. 
     Another aspect of the disclosed and claimed concept is to provide one or more circuit interrupters and/or one or more electrical enclosures wherein a circuit interrupter having a current carrying capability greater than the current rating of an electrical enclosure will be resisted from being electrically connected with such electrical enclosure. 
     These and other aspects of the disclosed and claimed concept are provided by an improved circuit interrupter having a current carrying rating, the circuit interrupter being structured to be installable in electrical connection with an electrical enclosure having a current rating at least equal to the current carrying rating and being structured to be non-installable in electrical connection with an electrical enclosure having a current rating less than the current carrying rating, the circuit interrupter can be generally stated as including an electrical interruption apparatus having a current carrying rating and comprising a housing and one or more of: a receptacle having a dimension, the dimension being structured to enable the receptacle to receive therein an elongated conductor of electrical enclosure having a current rating at least equal to the current carrying rating, the dimension being structured to resist at least one of: reception into the receptacle of a conductor of an electrical enclosure having a current rating less than the current carrying rating, and attachment of the circuit interrupter to a conductor of an electrical enclosure having a current rating less than the current carrying rating, a pair of receptacles that are spaced apart a distance, the distance being structured to enable the pair of receptacles to receive therein an elongated pair of conductors of an electrical enclosure having a current rating at least equal to the current carrying rating, the distance being structured to resist reception into the pair of receptacles of a pair of conductors of an electrical enclosure having a current rating less than the current carrying rating, and an exterior portion which is structured to be interfered with by an interference element of an electrical enclosure having a current rating less than the current carrying rating and which is thereby structured to resist electrical connection between the circuit interrupter and the electrical enclosure having the current rating less than the current carrying rating, the exterior portion being structured to be non-interfered with and to permit electrical connection of the circuit interrupter with an electrical enclosure having a current rating no less than the current carrying rating. 
     Other aspects of the disclosed and claimed concept are provided by an improved electrical enclosure having a current rating, the electrical enclosure being structured to receive in electrical connection therewith a circuit interrupter having a current carrying rating no greater than the current rating and being structured to resist electrical connection therewith of a circuit interrupter having a current carrying rating greater than the current rating, the electrical enclosure can be generally stated as including an electrical delivery apparatus having a current rating and comprising one or more of: an elongated conductor having a dimension, the dimension being structured to enable the conductor to be received in a receptacle of and to permit electrical connection with a circuit interrupter having a current carrying rating no greater than the current rating, the dimension being structured to resist at least one of: reception of the conductor in a receptacle of a circuit interrupter having a current carrying rating greater than the current rating, and attachment of the conductor into electrical connection with a circuit interrupter having a current carrying rating greater than the current rating, an elongated pair of conductors that are spaced apart a distance, the distance being structured to enable the pair of conductors to be receivable in a pair of receptacles of a circuit interrupter having a current carrying rating equal to or less than the current rating, the distance being structured to resist reception of the pair of conductors in a pair of receptacles of a circuit interrupter having a current carrying rating greater than the current rating, and an interference element that is structured to be engageable with and to thereby resist a circuit interrupter having a current carrying rating greater than the current rating from being electrically connected with the electrical enclosure, the interference element being structured to permit a circuit interrupter having a current carrying rating no greater than the current rating to be received in electrical connection with the electrical enclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A further understanding of the disclosed and claimed concept can be gained from the following Description when read in conjunction with the accompanying drawings in which: 
         FIG. 1  is a front elevational view of a first circuit interrupter in accordance with the disclosed and claimed concept; 
         FIG. 2  is a front elevational view of a first electrical enclosure, partially cut away, with which the circuit interrupter of  FIG. 1  can be electrically connected; 
         FIG. 3  is a front elevational view of a second circuit interrupter in accordance with the disclosed and claimed concept; 
         FIG. 4  is a front elevational view of a second electrical enclosure, partially cut away, with which the circuit interrupter of  FIG. 3  can be electrically connected; 
         FIG. 5  is a front elevational view of a third circuit interrupter in accordance with the disclosed and claimed concept; 
         FIG. 6  is a front elevational view of a third electrical enclosure, partially cut away, with which the circuit interrupter of  FIG. 5  can be electrically connected; 
         FIG. 7  is a top plan view of the first circuit interrupter of  FIG. 1 ; 
         FIG. 8  is a sectional view as taken along line  8 - 8  of the first circuit interrupter of  FIG. 1  as it would be installed on the first electrical enclosure of  FIG. 2 ; 
         FIG. 9  is a sectional view as taken along line  9 - 9  of the second circuit interrupter of  FIG. 3  as it would be installed on the second electrical enclosure of  FIG. 4 ; 
         FIG. 10  is a sectional view as taken along line  10 - 10  of the third circuit interrupter of  FIG. 5  as it would be installed on the third electrical enclosure of  FIG. 6 ; 
         FIG. 11  is a front elevational view of a fourth circuit interrupter in accordance with the disclosed and claimed concept mounted on a schematically depicted fourth electrical enclosure in accordance with the disclosed and claimed concept; and 
         FIG. 12  is a front elevational view of a fifth circuit interrupter in accordance with the disclosed and claimed concept mounted on a schematically depicted fifth electrical enclosure in accordance with the disclosed and claimed concept. 
     
    
    
     Similar numerals refer to similar parts throughout the specification. 
     DESCRIPTION 
     A first circuit interrupter  4  in accordance with the disclosed and claimed concept is depicted generally in  FIG. 1 . The first circuit interrupter  4  of  FIG. 1  is electrically connectable with a first electrical enclosure  8  in accordance with the disclosed and claimed concept that is depicted generally in  FIG. 2 . The first circuit interrupter  4  has a first current carrying rating, and the first electrical enclosure  8  has a first current rating, with the first current carrying rating being no greater than the first current rating. 
     As can be seen in  FIG. 1 , the first circuit interrupter  4  includes a housing  12  upon which is disposed an electrical interruption apparatus  14  which includes components that are not expressly depicted herein such as one or more sets of separable contacts, one or more trip mechanisms, one or more bimetal sensors, one or more magnetic trip elements, one or more current transformers, and the like without limitation. The housing can be said to include an exterior situated externally to the housing  12 . 
     The electrical interruption apparatus  14  includes a pair of electrical terminals  20  and  24  which have a pair of holes  28  and  32 , respectively, formed therein. The holes  28  and  32  serve as receptacles that enable electrical connections with the electrical terminals  20  and  24 . It can be seen from  FIG. 1  that the holes  28  and  32  are slightly elongated holes and each have a diameter  36 . The diameter  36  is indicated in the context of the hole  28  but is the same for the hole  32 , with the holes  28  and  32  each having the same diameter  36  across the smallest transverse dimension thereof. The holes  28  and  32  also are separated from one another by a first distance  40  which is indicated in  FIG. 1  as being represented by a center-to-center spacing between the holes  28  and  32 . The housing  12  additionally has a notch  44  ( FIGS. 7 and 8 ) formed therein at a portion of the exterior  16 , and it can be seen that the notch  44  is a void region from which the material that otherwise forms the housing  12  is absent. 
     The first electrical enclosure  8  can be seen in  FIG. 2  to have a housing  48  upon which is situated an electrical delivery apparatus  52 . The housing  48  can be said to be an enclosure apparatus and is depicted in a schematic fashion and without its typical cover for purposes of simplicity of disclosure. The same can be said of the other electrical enclosures that are described elsewhere herein. 
     The housing  48  includes a plate  56  or other structure that is mounted internally thereto and which has an opening  60  formed therein. The plate  56  has formed therein an interference element  64  which is depicted in  FIGS. 2 and 8  as being a hook-like protuberant structure or lug that is curved and is upstanding from the other portions of the plate  56 . 
     The electrical delivery apparatus  52  is schematically depicted in  FIG. 2  as including a pair of bus bars  68 A and  68 B to which are mounted a pair of studs  72 A and  72 B that are elongated and that protrude out of the plane of the page of  FIG. 2 . The studs  72 A and  72 B are each of a diameter  76  which is indicated in  FIG. 2  only in the context of the stud  72 A for purposes of simplicity of disclosure. That is, the studs  72 A and  72 B are both of the same diameter  76 , with the diameter  76  being a transverse dimension of the studs  72 A and  72 B that is measured transverse to their longitudinal extent (which, as set forth above, is out of the plane of the page of  FIG. 2 ). The studs  72 A and  72 B are separated apart by a distance that is represented by a spacing  80  between the studs  72 A and  72 B. 
     The diameter  76  of the studs  72 A and  72 B is equal to or slightly less than the diameter  36  of the holes  28  and  32 . Moreover, the distance between the studs  72 A and  72 B represented by the spacing  80  is equal to the first distance  40  between the holes  32  and  36 . As such, the studs  72 A and  72 B are receivable in the holes  28  and  32 , respectively. Moreover, and as can be seen in  FIG. 8 , the interference element  64  is receivable in the notch  44  when the studs  72 A and  72 B are received in the holes  28  and  32 , respectively. 
     The first circuit interrupter  4  is thus mountable on the first electrical enclosure  8  and is electrically connectable therewith. That is, the studs  72 A and  72 B, the interference element  64 , and the holes  28  and  32  are sized and positioned with respect to one another to permit the interference element  64  to be received in the notch  44  and to thus at least potentially be mechanically engaged with the housing  12  when the studs  72 A and  72 B are received in the holes  28  and  32 , respectively. In this regard, it can be seen in  FIG. 1  that the studs  72 A and  72 B are depicted in dashed lines as being receivable in the holes  28  and  32 , respectively. It can also be seen that the housing  12  in the depicted exemplary embodiment is at least partially received in the opening  60 . 
     Since the first current carrying rating of the first circuit interrupter  4  is no greater than the current rating of the first electrical enclosure  8 , the first circuit interrupter  4  is thus electrically connectable with the first electrical enclosure  8 , meaning that the first circuit interrupter  4  can be physically accommodated in or on the first electrical enclosure  8  and the electrical delivery apparatus  52  of the first electrical enclosure  8  can be electrically connected with the electrical interruption apparatus  14  of the first circuit interrupter  4 . In this regard, the interference element  64  does not interfere with the installation of the first circuit interrupter  4  in mechanical and electrical connection with the first electrical enclosure  8  since the notch  44  provides a void region into which the free end of the interference element  64  is receivable, whereby the notch  44  and the interference element  64  can be said to be non-interfering with one another and to thus rather permit the installation of the first circuit interrupter  4  on the first electrical enclosure  8 . 
     A second circuit interrupter in accordance with the disclosed and claimed concept is depicted generally in  FIG. 3  and can be said to have a second current carrying rating. The second circuit interrupter  104  is mountable to and electrically connectable with a second electrical enclosure  108  in accordance with the disclosed and claimed concept that is depicted generally in  FIG. 4 . The second electrical enclosure  108  has a second current rating. The second current carrying rating of the second circuit interrupter  104  is greater than the first current carrying rating of the first circuit interrupter  4 . Likewise, the second current rating of the second electrical enclosure  108  is greater than the first current rating of the first electrical enclosure  8 . It is noted, however, that the second current carrying rating of the second circuit interrupter  104  is no greater than the second current rating of the second electrical enclosure  108 , thereby permitting the second interrupter  104  to be mounted and electrically connected with the second electrical enclosure  108 . 
     The second circuit interrupter  104  is physically very similar to the first circuit interrupter  4  except that it includes a pair of the holes  128  and  132  formed in a pair of electrical terminals  120  and  124 , respectively, that are each of a diameter  136  that is relatively smaller than the diameter  36  of the holes  28  and  32  of the first circuit interrupter  4 . Another difference between the two, as suggested above, is that the second circuit interrupter  104  has a greater current carrying rating than that of the first circuit interrupter  4 . 
     In a fashion similar to the first circuit interrupter  4 , the second circuit interrupter  104  includes an electrical interruption apparatus  114  disposed on a housing  112  having an exterior  116 , a portion of which has a notch  144  formed therein. While the diameter  136  of the holes  128  and  132  is less than the diameter  36  of the holes  28  and  32 , a second distance  140  between the holes  128  and  132 , depicted herein as being a center-to-center distance, is equal to the first distance  40  between the holes  28  and  32 . 
     The second electrical enclosure  108  is depicted in  FIG. 4  as likewise being physically similar to the first electrical enclosure  8  except having a pair of studs  172 A and  172 B that are each of a diameter  176  that is smaller than the diameter  76  of the studs  72 A and  72 B. The studs  172 A and  172 B are separated apart by a distance that is represented by a spacing  180  in  FIG. 4 , and the depicted exemplary spacing  180  is equal to each of the second distance  140 , the first distance  40 , and the spacing  80 . The second electrical enclosure  108  has a housing  148  upon which is disposed an electrical delivery apparatus  152 , and the electrical delivery apparatus  152  includes a pair of bus bars  168 A and  168 B upon which the elongated studs  172 A and  172 B, respectively, are mounted. The housing  148  additionally has a plate  156 , an opening  160 , and an interference element  164  that are substantially the same as the plate  56 , the opening  60 , and the interference element  64  of the first electrical enclosure  8 . 
     It can be understood from  FIGS. 3 and 4  that the diameter  176  of the studs  172 A and  172 B is less than or equal to the diameter  136  of the holes  128  and  132 , and the spacing  180  between the studs  172 A and  172 B is equal to the second distance  140  between the holes  128  and  132 . As such, the studs  172 A and  172 B are receivable in the holes  128  and  132 , respectively. Moreover, and as can be seen in  FIG. 9 , the interference element  164  is receivable in a notch  144  formed in the housing  112  at the exterior  116 , which enables the second circuit interrupter  104  to be physically accommodated by the second electrical enclosure  108 , which includes being receivable in the opening  160 . 
     It is noted that since the spacing  180  between the studs  172 A and  172 B of the second electrical enclosure  108  is equal to the first distance  40  between the holes  28  and  32  of the first circuit interrupter  4 , and because the diameter  176  of the studs  172 A and  172 B is relatively smaller than the diameter  36  of the holes  28  and  32 , the first circuit interrupter  4  is mountable to and electrically connectable with the second electrical enclosure  108  whereby the interference element  164  would be receivable in the notch  44 . This is advantageous because the current carrying rating of the first circuit interrupter  4  is less than the second current rating of the second electrical enclosure  108 . That is, the first and second circuit interrupters  4  and  104  are each (alternatively) electrically connectable with the second electrical enclosure  108  since the first current carrying rating and the second current carrying rating of the first and second circuit interrupters  4  and  104 , respectively, are each no greater than the current rating of the second electrical enclosure  108 . 
     It is further noted, however, that despite the second distance  140  of the holes  128  and  132  being equal to the spacing  80  of the studs  72 A and  72 B, the second circuit interrupter  104  is not mountable to the first electrical enclosure  108  and rather is rejected from such installation since the diameter  76  of the studs  72 A and  72 B is larger than the diameter  136  of the holes  128  and  132 . This is likewise desirable because the second current carrying rating of the second circuit interrupter  104  is greater than the first current rating of the first electrical enclosure  108 . As such, while the first and second distances  40  and  140  and the spacing  180  are equal and thus permit either of the first and second circuit interrupters  4  and  104  to be installed in the second electrical enclosure  108 , the diameter  76  of the studs  72 A and  72 B being greater than the diameter  136  of the holes  128  and  132  resists and rejects the second interrupter  104  from being installed on the first electrical enclosure  8 . Again, while it is acceptable for the second electrical enclosure  108  to have installed therein a main circuit interrupter having a current carrying rating no greater than the second current rating, such as the first and second circuit interrupters  4  and  104 , the first electrical enclosure  8  advantageously rejects the installation of a main circuit interrupter such as the second circuit interrupter  104  having a current carrying rating greater than the first current rating. 
     A third circuit interrupter  204  in accordance with the disclosed and claimed concept is depicted generally in  FIG. 5  and is installable in a third electrical enclosure  208  in accordance with the disclosed and claimed concept that is depicted generally in  FIG. 6 . The third circuit interrupter  204  has a third current carrying rating which, in the depicted exemplary embodiment, is equal to a third current rating of the third electrical enclosure  208 . The third current carrying rating of the third circuit interrupter  204  is greater than both the first and second current carrying ratings of the first and second current interrupters  4  and  104 . Likewise, the third current rating of the third electrical enclosure  208  is greater than either of the first and second current ratings of the first and second electrical enclosures  8  and  108 . 
     The third circuit interrupter  204  includes a housing  212  upon which is disposed an electrical interruption apparatus  214 . The housing  212  has an exterior that is larger than either of the housings  12  and  112 , and that is likewise larger than either of the openings  60  and  160  in the first and second electrical enclosures  8  and  108 . Also, the interference elements  64  and  164  would interfere with the reception thereon of a web  242  of the housing  212  and other portions of the housing  212 . These features thus advantageously reject the third circuit interrupter  204  from being installed on either the first and second electrical enclosures  8  and  108 . 
     As can be seen in  FIG. 5 , the second circuit interrupter  204  has a pair of electrical terminals  220  and  224  having a pair of holes  228  and  232 , respectively, formed therein. A pair of studs  272 A and  272 B of the third electrical enclosure  208  are spaced and are sized to be accommodated in the holes  228  and  232 . The third electrical enclosure  208  includes a housing  248  having an electrical delivery apparatus  252  disposed thereon and further includes a plate  256  having an opening  260  formed therein and further having a threaded hole  262  formed therein. The third circuit interrupter  204  has a slot  246  formed in the web  242 , and a threaded fastener  256  is receivable through the slot  246  and in the threaded hole  262  to permit the third circuit interrupter  204  to be physically fastened to the third electrical enclosure  208 . 
     The electrical delivery apparatus  252  includes a pair of bus bars  268 A and  268 B to which the studs  272 A and  272 B, respectively, are mounted. As can be understood from  FIGS. 8, 9, and 10 , which are intended to be of the same scale, the housing  212  of the third circuit interrupter  204  is sufficiently large that it would be non-receivable in the openings  60  and  160  of the first and second electrical enclosures  8  and  108  and, as mentioned above, the interference elements  64  and  164  would interfere with the web  242  and other portions of the housing  212 , and vice versa. As such, the third circuit interrupter  204  is resisted and rejected from being installed on either of the first and second electrical enclosures  8  and  108 . 
     While the diameter and spacing of the studs  272 A and  272 B enables them to be physically received in the holes  228  and  232  and to be electrically connected with the electrical terminals  220  and  224 , such diameter and spacing of the studs  272 A and  272 B may or may not be configured to enable the first and second circuit interrupters  4  and  104  to be mounted on the third electrical enclosure  208 . That is, while the third circuit interrupter  204  is installable on the third electrical enclosure  208  but is resisted from being installed on the first and second electrical enclosures  8  and  108 , the first and second circuit interrupters  4  and  104  may or may not be installable on the third electrical enclosure  208  depending upon the needs of the particular application. That is, the diameter and spacing of the studs  272 A and  272 B could be configured to enable them to be electrically connected with the first and second circuit interrupters  4  and  104 , and the third electrical enclosure  208  potentially could include some type of physical structure that would be receivable in the notches  44  and  144  to enable installation of the first and second circuit interrupters  4  and  104  on the third electrical enclosure  208 , although such variability is not necessarily needed. For instance, if it is desired to provide such variability, the studs  272 A and  272 B can be sized and spaced to be accommodated in the holes  28  and  32  and the holes  128  and  132 . On the other hand, if such variability is unneeded or undesired, the diameter and spacing of the studs  272 A and  272 B need not necessarily be such as to enable connection of the first and second interrupters  4  and  104 . 
     It thus can be seen from the foregoing that the third circuit interrupter  204  is installable in the third electrical enclosure  208  but is resisted from and rejected from being installed on the first and second electrical enclosures  8  and  108 . And, depending upon the particular configuration of the third electrical enclosure  208 , the first and second circuit interrupters  4  and  104  potentially could be mounted on the third electrical enclosure  208  and electrically connected therewith. This is because the third circuit interrupter  204  and the third electrical enclosure  208  are such that a circuit interrupter having a given current carrying rating is resisted from being installed on an electrical enclosure having a current rating less than the given current carrying rating. 
     Moreover, while the first current interrupter  4  is installable on either of the first and second electrical enclosures  8  and  108 , the second current interrupter  104  is resisted and rejected from being installed on the first electrical enclosure  8  because the first and second circuit interrupters  4  and  104  and the first and second electrical enclosures  8  and  108  are configured such that a circuit interrupter having a given current carrying rating cannot be installed in an electrical enclosure having a current rating less than the given current carrying rating. While in some circumstances an electrical enclosure such as the first and second electrical enclosures  8  and  108  can have mounted therein a circuit interrupter such as the first and second circuit interrupters  4  and  104  so long as the current carrying rating is no greater than the current rating, an attempt to install a circuit interrupter having a particular current carrying rating into an electrical enclosure having a current rating less than the particular current carrying rating would be resisted and rejected. The circuit interrupters  4 ,  104 , and  204 , and the electrical enclosures  8 ,  108 , and  208  together and individually thus advantageously resist an electrical enclosure having a current rating from having mounted thereto a circuit interrupter having a current carrying rating greater than the current rating, whereas a circuit interrupter having a current carrying rating equal to or less than the current rating of the electrical enclosure may or may not be permitted depending upon the needs of the particular application. 
     A fourth circuit interrupter  304  and a fifth circuit interrupter  404  in accordance with the disclosed and claimed concept are depicted in  FIGS. 11 and 12 , respectively, as being installed in a schematically depicted fourth electrical enclosure  308  and a schematically depicted fifth electrical enclosure  408 , respectively, that are likewise in accordance with the disclosed and claimed concept. The fourth circuit interrupter  304  has a fourth current carrying rating that is different from a fifth current carrying rating of the fifth circuit interrupter  404 . The fourth electrical enclosure  308  has a fourth current rating that is greater than or equal to the fourth current carrying rating, and the fifth electrical enclosure  408  has a fifth current rating that is equal to or greater than the fifth current carrying rating. 
     The exemplary fourth and fifth circuit interrupters  304  and  404  are physically similar to one another. However, the fourth circuit interrupter  304  has an electrical interruption apparatus  314  that includes a pair of electrical terminals  320  and  324  having a pair of holes  328  and  332 , respectively, formed therein that are of a diameter  336  and that are spaced apart by a distance  340 . The fifth circuit interrupter  404  has an electrical interruption apparatus  414  that includes a pair of electrical terminals  420  and  424  having a pair of holes  428  and  432 , respectively, formed therein that are of a diameter  436  and that are spaced apart by a distance  440 . While the diameter  436  is equal to the diameter  336 , the distance  440  is different from the distance  340 . It thus can be understood that as an alternative to the different diameters  76  and  176  of the studs  72 A and  72 B and the studs  172 A and  172 B, the different distances  340  and  440  between the pair of studs  372 A and  372 B and the pair of studs  472 A and  472 B, respectively, can be likewise used to enable or reject installation of a circuit interrupter. Such enablement or rejection of installation of a circuit interrupter having a current carrying rating would depend upon whether the current rating of the electrical enclosure to which the circuit interrupter is intended to be installed is i) at least equal to or ii) less than the current carrying rating, respectively. 
     While the distance  340  between the holes  328  and  332  is equal to a spacing  380  between the pair of studs  372 A and  372 B, and the distance  440  between the holes  428  and  432  is equal to a spacing  480  between the pair of studs  472 A and  472 B, the distances  340  and  440  are different from one another, and the spacings  380  and  480  are likewise different from one another. It thus can be understood that the distance between the receptacles of the electrical terminals of a circuit interrupter and the distance between the studs of an electrical enclosure can additionally or alternatively control the installation or rejection of a given circuit interrupter on a given electrical enclosure in accordance with the relationships mentioned herein between the current carrying rating and the current rating thereof, respectively, or based upon other criteria which might desirably be employed in determining which circuit interrupters are mountable to which electrical enclosures. 
     While certain examples are presented herein wherein diameters of studs and holes and/or spacing between studs and holes and/or the use of interfering structures have been used, it is understood that any of the foregoing, individually or in combination, can be employed to effect the advantageous enabling or rejecting of the connection of circuit interrupters with electrical enclosures. 
     While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.