Abstract:
The present invention is directed to a protective device that includes a housing having a plurality of line terminals, a plurality of load terminals, and a plurality of user-accessible terminals accessible via apertures disposed in a front major surface of the housing. A fault detection assembly is coupled to the plurality of line terminals, the fault detection circuit being configured to provide a fault detection output in response to detecting a fault condition. A circuit interrupter is coupled to the fault detection assembly. The circuit interrupter includes a first set of interrupting contacts configured to provide electrical continuity between the plurality of line terminals, the plurality of load terminals, and the plurality of user-accessible terminals in a reset state. The first set of interrupting contacts are decoupled in response to the fault detection output to enter a tripped state such that the plurality of line terminals are decoupled from the plurality of load terminals and the plurality of user-accessible terminals. An auxiliary switch is coupled to the fault detection assembly. The auxiliary switch includes a second set of contacts configured to decouple at least a portion of the fault detection assembly from a source of electrical power in the tripped state. The second set of contacts being self-biased toward a predetermined switch position when no force is applied thereto. A latch block assembly is coupled to the circuit interrupter. The latch block assembly includes a first latch block portion and a second latch block portion. The first latch block portion is configured to drive the first set of contacts to close when transitioning from the tripped state to the reset state. The second latch block portion is configured to overcome the self bias of the second set of contacts to thereby drive the second set of contacts open when transitioning from the reset state to the tripped state.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of U.S. patent application Ser. No. 11/109,579, filed on Apr. 19, 2005, which is a continuation-in-part of U.S. patent application Ser. No. 10/901,688 filed on Jul. 29, 2004, the content of which is relied upon and incorporated herein by reference in its entirety, and the benefit of priority under 35 U.S.C. §120 is hereby claimed. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to electrical wiring devices, and particularly to electrical wiring devices including protective features. 
     2. Technical Background 
     AC power is coupled to an electrical distribution system at a breaker panel. The breaker panel is disposed within a residence, commercial building or some other such facility. The breaker panel distributes AC power to one or more branch electric circuits installed in the structure. The electric circuits may typically include one or more receptacle outlets and may further transmit AC power to one or more electrically powered devices, commonly referred to in the art as load circuits. The receptacle outlets provide power to user-accessible loads that include a power cord and plug, the plug being insertable into the receptacle outlet. However, certain types of faults have been known to occur in electrical wiring systems. Accordingly, each electric circuit typically employs one or more electric circuit protection devices. 
     Electric circuit protective devices may be disposed within the breaker panel, receptacle outlets, plugs and the like. Both receptacle wiring devices and electric circuit protective wiring devices are disposed in an electrically non-conductive housing. The housing includes electrical terminals that are electrically insulated from each other. In particular, line terminals couple the wiring device to conductors coupled to the breaker panel. Load terminals are coupled to wiring that directs AC power to one or more electrical loads. Those of ordinary skill in the pertinent art will understand that the term “load” refers to an appliance, a switch, or some other electrically powered device. 
     Load terminals may also be referred to as “feed-through” terminals because the wires connected to these terminals may be coupled to a daisy-chained configuration of receptacles or switches. The load may ultimately be connected at the far end of this arrangement. Referring back to the device housing, the load terminals may be electrically connected to a set of receptacle contacts. The receptacle contacts are in communication with receptacle openings disposed on the face of the housing. This arrangement allows a user to insert an appliance plug into the receptacle opening to thereby energize the device. 
     Protective devices employ a circuit interrupter disposed between the line terminals and the load terminals. The circuit interrupter provides power to the load terminals under normal conditions, but breaks electrical connectivity when the protective device detects a fault condition in the load circuit. 
     There are several types of electric circuit protection devices including ground fault circuit interrupters (GFCIs), ground-fault equipment protectors (GFEPs), and arc fault circuit interrupters (AFCIs). This list includes representative examples and is not meant to be exhaustive. Some devices include both GFCIs and AFCIs. As their names suggest, arc fault circuit interrupters (AFCIs), ground-fault equipment protectors (GFEPs) and ground fault circuit interrupters (GFCIs) perform different functions. 
     An arc fault typically manifests itself as a high frequency current signal. Accordingly, an AFCI may be configured to detect various high frequency signals and de-energize the electrical circuit in response thereto. A ground fault occurs when a current carrying (hot) conductor creates an unintended current path to ground. A differential current is created between the hot/neutral conductors because some of the current flowing in the circuit is diverted into the unintended current path. The unintended current path represents an electrical shock hazard. Ground faults, as well as arc faults, may also result in fire. 
     A “grounded neutral” is another type of ground fault. This type of fault may occur when the load neutral terminal, or a conductor connected to the load neutral terminal, becomes grounded. While this condition does not represent an immediate shock hazard, it may lead to serious hazard. As noted above, a GFCI will trip under normal conditions when the differential current is greater than or equal to approximately 6 mA. However, when the load neutral conductor is grounded the GFCI becomes de-sensitized because some of the return path current is diverted to ground. When this happens, it may take up to 30 mA of differential current before the GFCI trips. Therefore, if a double-fault condition occurs, i.e., if the user comes into contact with a hot conductor (the first fault) when simultaneously contacting a neutral conductor that has been grounded on the load side (the second fault), the user may experience serious injury or death. 
     However, a protective device, like all electrical devices, has a limited life expectancy. This poses a problem in that when the device has reached end of life, the user may not be protected from the fault condition. End of life failure modes include failure of device circuitry, the circuit interrupter that opens (trips) the GFCI interrupting contacts, the relay solenoid that opens the GFCI interrupting contacts, and /or the solenoid switching device. Switching devices include thyristors such as the silicon controlled rectifiers (SCRs). An end of life failure mode can result in the protective device not protecting the user from the faults referred to above. 
     In one approach that has been considered, a test buttons is incorporated into a protective device to provide the user with a means for testing the effectiveness of the device. One drawback to this approach lies in the fact that if the user fails to use the test button, the user will not know if the device is functional. Even if the test is performed, the test results may be ignored by the user for various reasons. 
     What is needed is a protective device that denies power to the protected circuit when the device is non-protective. What is needed is a protective device that denies power to the protected circuit when the SCR is experiencing an end of life condition. What is needed is an auxiliary switch designed to have an improved reliability. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a protective device that denies power to an electric circuit when the device loses its protective functionality. In particular, the protective device of the present invention denies power to the protected circuit when the SCR is experiencing an end of life condition. The present invention accomplishes the power denial using an auxiliary switch designed to have an improved reliability. 
     One aspect of the present invention is directed to a protective device that includes a housing having a plurality of line terminals, a plurality of load terminals, and a plurality of user-accessible terminals accessible via apertures disposed in a front major surface of the housing. A fault detection assembly is coupled to the plurality of line terminals, the fault detection circuit being configured to provide a fault detection output in response to detecting a fault condition. A circuit interrupter is coupled to the fault detection assembly. The circuit interrupter includes a first set of interrupting contacts configured to provide electrical continuity between the plurality of line terminals, the plurality of load terminals, and the plurality of user-accessible terminals in a reset state. The first set of interrupting contacts are decoupled in response to the fault detection output to enter a tripped state such that the plurality of line terminals are decoupled from the plurality of load terminals and the plurality of user-accessible terminals. An auxiliary switch is coupled to the fault detection assembly. The auxiliary switch includes a second set of contacts configured to decouple at least a portion of the fault detection assembly from a source of electrical power in the tripped state. The second set of contacts being self-biased toward a predetermined switch position when no force is applied thereto. A latch block assembly is coupled to the circuit interrupter. The latch block assembly includes a first latch block portion and a second latch block portion. The first latch block portion is configured to drive the first set of contacts to close when transitioning from the tripped state to the reset state. The second latch block portion is configured to overcome the self bias of the second set of contacts to thereby drive the second set of contacts open when transitioning from the reset state to the tripped state. 
     In another aspect, the present invention is directed to a device including a housing including a plurality of line terminals, a plurality of load terminals, and a plurality of user-accessible terminals accessible via apertures disposed in a front major surface of the housing. An electromechanical assembly is coupled to the plurality of line terminals. The electromechanical assembly is configured to selectively generate a magnetic field in response to at least one predetermined condition. The electromechanical assembly includes a moveable mechanism responsive to the magnetic field, the moveable mechanism being actuatable between a reset position and a tripped position. A circuit interrupter portion is coupled between the plurality of line terminals and the plurality of load terminals. The circuit interrupter portion is responsive to the moveable mechanism. The circuit interrupter portion includes four sets of interrupting contacts that are configured to provide electrical continuity between the plurality of line terminals and the plurality of load terminals in the reset position and be electrically discontinuous in the tripped position. The device also includes an auxiliary switching portion that is responsive to the moveable mechanism and configured to deactivate at least a portion of the electromechanical assembly in the tripped position. The moveable mechanism sequentially moves the auxiliary switching portion relative to the circuit interrupter portion in a predetermined sequence. 
     In yet another aspect, the present invention is directed to a protective device includes a housing including a plurality of line terminals and a plurality of load terminals, the plurality of load terminals including a plurality of feed-through terminals and a plurality of user-accessible terminals accessible via apertures disposed in a front major surface of the housing. An electromechanical assembly is coupled to the plurality of line terminals. The electromechanical assembly is configured to provide at least one output when detecting at least one predetermined condition. A circuit interrupter is coupled between the plurality of line terminals and the plurality of load terminals. The circuit interrupter includes four sets of interrupting contacts configured to provide electrical continuity between the plurality of line terminals and the plurality of load terminals in a reset state and decouple the four sets of interrupting contacts in response to the at least one output to drive the four sets of interrupting contacts into a tripped state. The four sets of interrupting contacts are configured to be biased toward the tripped state. An auxiliary switching mechanism is coupled to the electro-mechanical assembly. The auxiliary switching mechanism is configured to deactivate at least a portion of the electromechanical assembly from a source of electrical power in response to the at least one output, the auxiliary switching mechanism being self-biased toward an open switch state. A latching assembly is coupled to the circuit interrupter. The latching assembly includes a first portion configured to close the four sets of interrupting contacts when transitioning from the tripped state to the reset state. The latching assembly further includes a second portion configured to open the auxiliary switching mechanism when transitioning from the reset state to the tripped state. A user-accessible reset mechanism is coupled between the circuit interrupter and the latching assembly. The user-accessible reset mechanism is configured to close the four sets of interrupting contacts and close the auxiliary switching mechanism in a predetermined sequence when transitioning from the tripped state to the reset state. 
     Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description which follows, the claims, as well as the appended drawings. 
     It is to be understood that both the foregoing general description and the following detailed description are merely exemplary of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the invention, and together with the description serve to explain the principles and operation of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic of a circuit protection device in accordance with one embodiment of the present invention; 
         FIG. 2  is a perspective view of a mechanical implementation of the electrical wiring device shown in  FIG. 1 . 
         FIG. 3  is a perspective view of a mechanical embodiment of a wiring device in accordance with another embodiment of the present invention; 
         FIG. 4  is a detail view of the trip mechanism shown in  FIG. 2 ; 
         FIG. 5  is a detail view of the trip mechanism shown in  FIG. 2 ; 
         FIG. 6  is a detail view of the trip mechanism shown in  FIG. 2 ; 
         FIG. 7  is a detail view of the auxiliary switch shown in  FIG. 2 ; 
         FIG. 8  is a detail view of the auxiliary switch shown in  FIG. 2 ; 
         FIG. 9  is a detail view of the auxiliary switch shown in  FIG. 2 ; 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the present exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. An exemplary embodiment of the protective device of the present invention is shown in  FIG. 1 , and is designated generally throughout by reference numeral  10 . 
     As embodied herein, and depicted in  FIG. 1 , a schematic of a circuit protection device  10  in accordance with an embodiment of the present invention is disclosed. GFCI  10  includes ground fault interrupter circuitry. Device  10  includes line terminals  112 ,  114 , load terminals  116 ,  118 , and receptacle terminals  120 ,  122 . Load terminals  116 ,  118  may also be referred to as feed-through terminals. As noted above, these terminals may be connected to wiring configured to provide power to downstream receptacles or switches. Receptacle load terminals  120 , 122  are configured to mate with an electrical plug to provide power to an appliance or other such user attachable loads. The line terminals  112 ,  114  are electrically connected to both load terminals  116 ,  118  and receptacle terminals  120 ,  122  when device  10  is reset. When in the tripped state, the circuit interrupter  124  disconnects the load terminals from the line terminals. In addition, the circuit interrupter may disconnect at least one feed-through terminal from a corresponding receptacle terminal. 
     The ground fault circuitry includes a differential transformer  126  which is configured to sense load-side ground faults. Transformer  128  is configured as a grounded neutral transmitter and is employed to sense grounded-neutral fault conditions. Both differential transformer  126  and grounded-neutral transformer  128  are coupled to detector circuit  130 . Power supply  132  provides power for GFI detector circuit  130 . Detector  130  provides an output signal on output pin  134  based on the transformer outputs. The detector output signal is filtered by circuit  136 . The filtered output signal is provided to the control input of SCR  138 . When SCR  138  is turned ON, solenoid  140  is energized. Solenoid  140  actuates the trip mechanism  142  to thereby trip circuit interrupter  124 . The trip solenoid  140  is energized until the circuit interrupter trips to remove the fault condition. Accordingly, there is no signal at output  134  and SCR  138  is turned OFF. The time that the solenoid remains energized is less than about  25  milliseconds. After the fault condition has been eliminated, circuit interrupter  124  may be reset by way of reset button  145 . 
     Although  FIG. 1  has disclosed a ground fault circuit interrupter circuit, those of ordinary skill in the art will understand that the present invention should not be construed as being limited to GFCIs. The present invention is suitable for use in other types of protective devices. For example, the sensor in an AFCI is similar to transformer  126  but is typically configured to sense load current by way of a toroidal transformer or a shunt and/or line voltage by way of a voltage divider. The detector in an AFCI is similar to detector  130  but is configured to detect an arc fault condition on the basis of frequency spectra or high frequency noise bursts. Once an arc fault condition is detected, a signal is sent in a similar manner to an SCR which in turn activates a trip mechanism to trip the circuit interrupter. Thus the spirit of the invention disclosed herein applies to GFCIs and to protective devices in general. 
     The present invention addresses certain end of life conditions by denying power when the device is unable to function. One end of life condition may cause the solenoid to be energized when a fault condition is not present, or if the circuit interrupter is in a tripped state. For example, the solenoid is susceptible to burn-out if SCR  138  is permanently ON. The solenoid may also be energized if the SCR  138  is permanently shorted out. Note that most solenoids are configured to be energized only momentarily and bum out if energized for more than about 1 second. Once the solenoid bums out, the circuit interrupter is incapable of being tripped. As a result, the load terminals are permanently connected to the line terminals even when there is a fault condition. 
     Solenoid burn-out may be prevented by an auxiliary switch  144 . Auxiliary switch  144  is configured to open when circuit interrupter  124  is in the tripped position. If SCR  38  is shorted, or is permanently ON, auxiliary switch  144  ensures that solenoid  140  is not permanently connected to a current source. Accordingly, if reset button  145  is activated, circuit interrupter  124  resets but immediately trips in response to the trip mechanism  142 , which in turn moves auxiliary switch  144  to the open position before solenoid  140  is able to burn out. 
     The auxiliary switch  144  affords other electrical benefits. Those of ordinary skill in the art will understand that a metal oxide varistor (MOV) is frequently employed in protective devices to protect the electrical circuit from voltage surges that sometimes occur in the electrical distribution system. The end-of-life failure mode of a MOV is typically an electrical short. The resulting current can be enough to thermally damage the enclosure of the protective device. In one embodiment of the present invention, MOV  146  is connected in series with auxiliary switch  144  and trip solenoid  140  to eliminate any over-current situation. Thus, when MOV  146  reaches end of life and shorts out, trip solenoid  140  is energized to open auxiliary switch  140  and the flow of short circuit current is terminated before any damage ensues. 
     Another beneficial feature of the present invention is provided by disposing indicator  148  in parallel with auxiliary switch  144 . In this embodiment, indicator  148  is implemented as a trip indicator, emitting a visual and/or audible indicator signal when circuit interrupter  124  is in the tripped state, i.e., when the auxiliary switch  144  is open. Of course, indicator  148  provides no such signal when device  10  is in a reset state. Again, indicator  148  may include visual indication, audible indication or both. The indicator may also be configured to emit a repetitive signal (flashing or beeping). A visual indicator may be a flashing red indicator. 
     As embodied herein and depicted in  FIG. 2 , a perspective view of a mechanical implementation of the electrical wiring device shown in  FIG. 1  is disclosed. Protective device  10  includes a circuit board  200  which is mounted inside the device housing (not shown). Transformer assembly  202  includes a housing that encloses ground fault transformer  126  and grounded-neutral transformer  128 , which are mounted on circuit board  200 . Line hot cantilever  204  and line neutral cantilever  206  are connected to line hot terminal  112  and line neutral terminal  114 , respectively. The other ends of the cantilevers are connected to contacts  208  (not shown) and  210 . Load hot cantilever  212  and load neutral cantilever  214  are respectively connected to load hot terminal  116  and load neutral terminal  118 . The other ends of the cantilevers are connected to doubled-sided contacts  216 ,  218 . Receptacle terminals  120 ,  122  are connected to contacts  222 ,  224 . When circuit interrupter  124  is in the tripped condition, the line contacts  208 ,  210  are electrically disconnected from load contacts  216 ,  218  and receptacle contacts  222 ,  224 . In another embodiment, cantilevers  204 ,  206 ,  212  and  214  may be self-biased toward a tripped state. Springs may also be used to provide biasing. 
     The circuit interrupter  124  may be reset by depressing reset button  145 . As reset button  145  is released, latch block  226  lifts cantilevers  204 ,  206 ,  212 , and  214  in an upward direction until contacts  208 ,  210  electrically engage contacts  216 ,  218 , and contacts  216 ,  218  electrically engage contacts  222 ,  224 . In the reset state, of course, the respective hot and neutral line terminals, receptacle load terminals, and feed through load terminals are electrically connected. 
     Those of ordinary skill in the art will understand that the contacts used in the circuit interrupter and the auxiliary switch may be implemented using any suitable means including conductive plating, conductive portions of cantilever members, conductive portions of fixed or substantially fixed members, conductive protuberances, and/or any other suitable means for conducting electrical current from one member to another. 
     Circuit interrupter  124  remains reset until such time as a fault condition is detected and trip mechanism  142  decouples latch block  226  from cantilevers  204 ,  206 . Once the latch block is decoupled from the cantilevers, the cantilevers move to their tripped positions in the described manner. 
     The mechanical implementation in accordance with one embodiment of the present invention is also depicted in  FIG. 2 . In particular, auxiliary switch  144  is implemented by movable cantilever  250  and fixed cantilever  254 . Moveable cantilever  250  includes a contact  252 , whereas fixed member  254  includes contact  256 . Cantilever  250  and/or contact member  254  may be mounted to printed circuit board  200 . In operation, when circuit interrupter  124  is reset, latch block  226  deflects cantilever  250  until contacts  252  and  256  engage each other to close the circuit and establish electrical connectivity. Cantilever member  254  may deflect when contact  252  applies force to contact  256 . When the force applied to cantilever  250  is released, the switch opens. Note that cantilever  250  is self biased to return to the open position. 
     One feature of the present invention is that also protects device  10  in the event that auxiliary switch  144  itself is subject to various possible end of life conditions that prevent the protective device from being able to interrupt a fault condition. Examples of such conditions include the welding together of the auxiliary switch contacts to an extent that they cannot be physically separated by the trip mechanism. Another example is that a contact of the auxiliary switch is contaminated with an electrically non-conductive substance that prevents the switch contacts from being electrically connected. Another end of life condition relates to the wear and tear of the trip mechanism such that the auxiliary switch remains open when the interrupting contacts are closed. Yet another example of an end of life condition relates to the closure of the auxiliary switch being prevented (in the reset state) by the presence of dirt, or some other foreign matter. The auxiliary switch  144  may experience an end of life condition due to mechanical wear and tear. 
     The auxiliary switch is called upon to initiate and then maintain a current level through power supply  132  of typically 8 milliamperes when the device  10  is reset. The auxiliary switch is also used to conduct the current that energizes the solenoid, which is typically about 3 amperes. Of course, this current is present each time device  10  is tripped. Electronic components may be connected to auxiliary switch  144  to mitigate any electrical arcing that might contribute to an end of life condition. In one embodiment (See  FIG. 1 ) this is implemented using a capacitor  152 , which is connected in parallel with the auxiliary switch  144 . Capacitor  152  serves to absorb energy when the contacts open, thus reducing the amount of energy available to form the arc. A resistor may be disposed in series with the capacitor (not shown). 
     As shown in  FIG. 2 , a secondary latch block  226 ′ is included. An advantage for subdividing the latch block into two parts is that the second latch block includes portions disposed above one or more of the cantilevers whose purpose is to be described. On the other hand, latch block  226  includes portions disposed below the cantilevers. The two part latch block configuration permits the trip mechanism  142  portion to be manufactured in a top-down manner. 
     Latch block  226 ′ ensures that contacts are capable of opening even if there is an end of life condition. Latch block  226 ′ is configured to move in an upward direction in response to the upward motion of latch block  226  when circuit interrupter  124  is being reset. On the other hand, when circuit interrupter  124  trips, latch block  226  moves in a downward direction due to a downward force exerted by an at least one spring  260 . The downward force is also applied to latch block  226 ′. Latch block  226 ′ includes an arm  262  that applies a downward force on the auxiliary switch  144 . The force is employed to open the auxiliary switch  144  if the self-biasing opening force in cantilever  250  because of one of the end of life conditions described above. Latch block  226 ′ may include other arms  264 ,  266 ,  268 ,  270  that also apply downward forces to cantilevers  204 ,  206 ,  212 ,  214 , respectively. Again, the applied force is configured to overcome dirt, foreign material, welding, or the like that may prevent the opening of the respective contacts when there is an end of life condition. 
     In an alternate embodiment, cantilever  250  is pre-biased such that auxiliary switch  144  is disposed in the closed position. Thus, switch  144  is opened by a force applied to it by latch blocks  226 ,  226 ′. Latch block  226 , disposed beneath cantilever  250 , moves in an upward direction during a reset action to close the auxiliary switch  144  if the self-biasing closing force in cantilever  250  is incapable of doing so. During tripping, arm  262  applies a downward force to open auxiliary switch  144 . 
     Similarly, cantilevers  204 ,  206 ,  212 ,  214  may also be pre-biased such that their respective contacts are in the closed position if force is not applied to them by latch blocks  226 ,  226 ′. Latch block  226 , disposed beneath the cantilevers, moves in an upward direction during a reset action to close the load contacts if the self-biasing closing forces in the cantilevers are incapable of doing so as a result of an end of life condition. During tripping, arms  264 ,  266 ,  268 ,  270  apply a downward force to open the load contacts. 
     Referring to  FIG. 3 , a perspective view of a mechanical embodiment of a wiring device in accordance with another embodiment of the present invention is disclosed. The schematic shown in  FIG. 1  is also applicable to the alternate embodiment. This embodiment is similar to that shown in  FIG. 2  except that auxiliary switch  144  includes bifurcated contacts. Auxiliary switch  144  is closed when circuit interrupter  124  is reset and is open when the circuit interrupter is tripped. However, auxiliary switch  144  includes two cantilevers  250 ′,  250 ″ instead of a single cantilever  250 . Cantilever  250 ′ includes contact  252 ′ and cantilever  250 ″ includes a contact  252 ″. Fixed member  254  includes contacts  256 ′,  256 ″ which are configured to mate with contacts  252 ′ and  252 ″. Cantilevers  250 ′,  250 ″ and/or contact member  254  are also mounted to printed circuit board  200 . 
     In operation, when circuit interrupter  124  is being reset, latch block  226  deflects cantilevers  250 ′,  250 ″ until contact pairs  252 ′,  256 ′ and  252 ″,  256 ″ engage. Fixed member  254  may be configured to deflect somewhat when contacts  252 ′,  252 ″ engage contacts  256 ′,  256 ″. When circuit interrupter  124  is tripped, latch block  226  the force applied to cantilevers  250 ′,  250 ″ is released. Note that cantilevers  250 ′,  250 ″ are self-biased to return to the open position. Electrical connectivity need only be established between one contact pair in order for the auxiliary switch to be closed. Thus if an end of life condition prevents one pair of contacts from closing, the second contact pair permits the auxiliary switch to still be in an operative condition. 
     Referring to  FIG. 4-6 , a perspective view of the trip mechanism shown in  FIGS. 2 and 3  is disclosed. For sake of clarity,  FIGS. 4-6  illustrate the manner in which the trip mechanism  142  operates relative to the neutral terminals. 
       FIG. 4  depicts trip mechanism  142  in the reset condition. Reset button  145  includes a stem portion  280  that is slidable within hole  282  of latch block  226 . Latch  284 , return spring  286 , and latch block  226  are pre-assembled to form a latch subassembly. Latch  284  is slidable relative to latch block  226 . Spring  286  forces latch  284  to partially occlude hole  282 . Thus, escapement  288  lifts latch block  226  upward to close contacts  210 ,  218 , and  224  to effect a reset state. 
     In particular, when reset button  145  is depressed, stem  280  moves downward and the bulbous portion of stem  280  pushes latch  284  to the right until the bulbous portion is entirely through the hole in latch  284 . Once the bulbous portion is through the hole in latch  284 , latch  284  moves in a leftward direction, due to force exerted on it by spring  286 , until the latch becomes seated on the escapement. When reset button  145  is released, it is directed in the upward direction, as indicated by directional arrow “A”, by the force exerted on it by reset spring  290 . Since latch  284  is seated on escapement  288 , the latch and the two latch blocks  226 ,  226 ′ are likewise directed upward. 
     Latch block  226  includes an arm  230  that deflects cantilever  206  that in turn deflects cantilever  214  until contacts  210 ,  218  come to rest on contact  224 . Of course, the neutral line and load terminals are electrically connected when contacts  210 ,  218  and  224  are connected together. 
       FIG. 5  shows circuit interrupter  124  during the tripping process. Solenoid  140  is energized in response to a trip signal. In response, a magnetic force is exerted on armature  141  to move the armature in the direction indicated by directional arrow B. Armature  141  overcomes the force of spring  286  and pushes latch  284  to the right. When latch  284  is no longer seated on escapement  288 , the bulbous portion of stem  280  becomes aligned with the hole in latch  284 . 
     Referring to  FIG. 6 , when reset button  145  is no longer held back by escapement  288 , it moves in direction A in response to the spring force exerted on button  145  by spring  290 . Since the escapement  288  is no longer aligned with respect to latch  284 , stem  280  and the bulbous portion move through the hole in latch  284  without escapement  288  reseating itself. Thus, latch  284  is decoupled from reset stem  280 , and latch  284 , and the two latch blocks  226 ,  226 ′ move in a downward direction (See directional arrow “C”) in response to the force exerted on latch block  226 ′ by break spring  292 . Cantilevers  206 ,  214  are also self-biased to move in direction C to the tripped state. Contacts  210 ,  218 , and  224  are no longer connected. An additional spring may be included to move the cantilever to the open position (not shown.) 
     Referring to  FIG. 7-9 , a detail view of the auxiliary switch shown in  FIGS. 2 and 3  is disclosed. Latch block  226  includes an arm  234  that is configured to deflect cantilever  250 . Cantilever  250  includes contact  252  which engages contact  256  when cantilever  250  is deflected. This occurs when circuit interrupter  124  is in a reset state. 
       FIG. 8  shows the auxiliary switch immediately prior to tripping, and therefore, shows auxiliary switch  145  at the same moment in time depicted in  FIG. 5 . Again, armature  141  overcomes the force of spring  286  and pushes latch  284  to the right. When latch  284  is no longer seated on escapement  288 , the bulbous portion of stem  280  becomes aligned with the hole in latch  284 . 
       FIG. 9  depicts the auxiliary switch immediately after tripping. Cantilever  250  may be pre-biased to move to the open position. As noted above, when the bulbous portion of stem  280  moves through the hole in latch  284 , latch  284 , latch block  226 , and latch block  226 ′ move in a downward direction. In one embodiment, latch block  226 ′ may include an arm  262  which is configured to strike cantilever  250  as latch block  226 ′ moves downwardly. The striking force is configured to separate contact  252  from contact  256  in the event that they become adhered to one another through a welding action or by some other means. Accordingly, arm  262  is an ancillary means for opening auxiliary switch  144  if the pre-biasing force alone in incapable of opening the auxiliary switch due to the occurrence of an end of life condition. 
     Note that the auxiliary switch  144  is configured to close before contacts  208 ,  216 ,  222  and  210 ,  218 ,  224  close. Otherwise, when the circuit interrupter  124  is being reset, the load terminals are live while the auxiliary switch is open. If the auxiliary switch is open, the trip solenoid  140  cannot energize to interrupt a fault condition. On the other hand, if the auxiliary switch is closed first, the protective device is functioning at the moment the load contacts close. The desired contact closing sequence is implemented by latch blocks  226 ,  226 ′. Latch block  226  guides the movable contacts  208 ,  210  and  252  from the open to the closed position by way of arms  230 ,  232  (not shown), and  234 . Note the arm  232  is identical to arm  234 , but it operates the cantilever in the hot conductive path. Stationary contact  256  may be disposed on latch block  226 ′ in a fixed spatial relationship relative to contacts  222 ,  224 . The excursion distances of the movable contacts are also in predetermined spatial relationship. 
     When the device is in the act of tripping, the auxiliary switch  144  may be configured to open after contacts  208 ,  216 ,  222  and  210 ,  218 ,  224  open. Normally the contacts open simultaneously under the guidance of trip mechanism  142 . However, one or more load contact may be welded due to an end of life condition. Given this circumstance, arms  264 ,  266 ,  268 ,  270  may be positioned so as to break the welded condition to assure that the load terminals  116 ,  118 ,  120 ,  122  are disconnected from the line terminals  112 ,  114  before arm  262  acts to open auxiliary switch  144 . 
     In an alternate embodiment the auxiliary switch  144  may be self-biased in the closed position, wherein arm  234  may be used as an ancillary method for closing the auxiliary switch. Thus auxiliary switch  144  is closed before arms  230 ,  232  proceed to close the load contacts  208 ,  210 . 
     As noted previously, the contacts normally open under the guidance of trip mechanism  142 . However, one or more load contact may be welded due to an end of life condition. Given this circumstance, arms  264 ,  266 ,  268 ,  270  are configured to break the welded condition to assure that the load terminals  116 ,  118 ,  120 ,  122  are disconnected from the line terminals  112 ,  114  before arm  262  acts to open auxiliary switch  144 . 
     Reference is made to U.S. application Ser. No. 10/900,769 and U.S. application Ser. No. 10/953,805, which are incorporated herein by reference as though fully set forth in its entirety, for a more detailed explanation of circuit interrupter configurations employed by the present invention. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.