Patent Publication Number: US-8988183-B2

Title: Fusible switching disconnect modules and devices

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. application Ser. No. 12/483,078 filed Jun. 11, 2009, entitled Fusible Switching Disconnect Modules and Devices and now issued U.S. Pat. No. 8,089,335, which is a continuation application of U.S. application Ser. No. 11/603,454 filed Nov. 22, 2006, entitled Fusible Switching Disconnect Modules and Devices and now issued U.S. Pat. No. 7,561,017, which is a continuation-in-part application of U.S. application Ser. No. 11/274,003 filed Nov. 15, 2005, entitled Fusible Switching Disconnect Modules and Devices and now issued U.S. Pat. No. 7,474,194, which is a continuation-in-part application of U.S. application Ser. No. 11/222,628 filed Sep. 9, 2005, entitled Fusible Switching Disconnect Modules and Devices and now issued U.S. Pat. No. 7,495,540, which claims the benefit of U.S. Provisional Application Ser. No. 60/609,431 filed Sep. 13, 2004, the disclosures of which are hereby incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates generally to fuses, and, more particularly, to fused disconnect switches. 
     Fuses are widely used as overcurrent protection devices to prevent costly damage to electrical circuits. Fuse terminals typically form an electrical connection between an electrical power source and an electrical component or a combination of components arranged in an electrical circuit. One or more fusible links or elements, or a fuse element assembly, is connected between the fuse terminals, so that when electrical current through the fuse exceeds a predetermined limit, the fusible elements melt and opens one or more circuits through the fuse to prevent electrical component damage. 
     In some applications, fuses are employed not only to provide fused electrical connections but also for connection and disconnection, or switching, purposes to complete or break an electrical connection or connections. As such, an electrical circuit is completed or broken through conductive portions of the fuse, thereby energizing or de-energizing the associated circuitry. Typically, the fuse is housed in a fuse holder having terminals that are electrically coupled to desired circuitry. When conductive portions of the fuse, such as fuse blades, terminals, or ferrules, are engaged to the fuse holder terminals, an electrical circuit is completed through the fuse, and when conductive portions of the fuse are disengaged from the fuse holder terminals, the electrical circuit through the fuse is broken. Therefore, by inserting and removing the fuse to and from the fuse holder terminals, a fused disconnect switch is realized. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an exemplary fusible switching disconnect device. 
         FIG. 2  is a side elevational view of a portion of the fusible switching disconnect device shown in  FIG. 1  in a closed position. 
         FIG. 3  is a side elevational view of a portion of the fusible switching disconnect device shown in  FIG. 1  in an open position. 
         FIG. 4  is a side elevational view of a second embodiment of a fusible switching disconnect device. 
         FIG. 5  is a perspective view of a third embodiment of a fusible switching disconnect device. 
         FIG. 6  is a perspective view of a fourth embodiment of a fusible switching disconnect device. 
         FIG. 7  is a side elevational view of the fusible switching disconnect device shown in  FIG. 7 . 
         FIG. 8  is a perspective view of a fifth embodiment of a fusible switching disconnect device. 
         FIG. 9  is a perspective view of a portion of the fusible switching disconnect device shown in  FIG. 8 . 
         FIG. 10  is a perspective view of a sixth embodiment of a fusible switching disconnect device. 
         FIG. 11  is a perspective view of a seventh embodiment of a fusible switching disconnect device. 
         FIG. 12  is a perspective view of an eighth embodiment of a fusible switching disconnect device in a closed position. 
         FIG. 13  is a side elevational view of a portion of the fusible switching disconnect device shown in  FIG. 12 . 
         FIG. 14  is a perspective view of the fusible switching disconnect device shown in  FIGS. 12 and 13  in an opened position. 
         FIG. 15  is a side elevational view of a portion of the fusible switching disconnect device shown in  FIG. 14 . 
         FIG. 16  is a perspective view of a ganged arrangement of fusible switching devices shown in  FIGS. 12-15 . 
         FIG. 17  is a perspective view of a ninth embodiment of a fusible switching disconnect device in a closed position. 
         FIG. 18  is a side elevational view of a portion of the fusible switching disconnect device shown in  FIG. 17 . 
         FIG. 19  is a side elevational view of the fusible switching disconnect device shown in  FIG. 17  in an opened position. 
         FIG. 20  is a perspective view of the fusible switching disconnect device shown in  FIG. 19 . 
         FIG. 21  is a perspective view of the fusible switching disconnect device shown in  FIG. 20  in a closed position. 
         FIG. 22  is a side elevational view of the fusible switching device shown in  FIG. 21 . 
         FIG. 23  is a perspective view of a tenth embodiment of a fusible switching disconnect device. 
         FIG. 24  is a perspective view of a portion of the fusible switching disconnect device shown in  FIG. 23 . 
         FIG. 25  is a perspective view of an eleventh embodiment of a fusible switching disconnect device. 
         FIG. 26  is a perspective view of a portion of the fusible switching disconnect device shown in  FIG. 25 . 
         FIG. 27  is a schematic diagram of the fusible switching disconnect device shown in  FIG. 26 . 
         FIG. 28  is a side elevational view of a portion of a twelfth embodiment of a fusible switching disconnect device. 
         FIG. 29  is a side elevational view of a portion of a thirteenth embodiment of a fusible switching disconnect device. 
         FIG. 30  is a perspective view of a fuse status indicator module for a fusible disconnect device. 
         FIG. 31  is a side elevational view of a portion of the module shown in  FIG. 30 . 
         FIG. 32  is an exemplary fuse status indicating circuit schematic for the module shown in  FIGS. 30 and 31 . 
         FIG. 33  is a perspective view of the fuse status indicator module shown in  FIGS. 30 and 31  connected to a fusible disconnect device. 
         FIG. 34  schematically illustrates a fused electrical system including the fusible disconnect device and fuse state indication module shown in  FIG. 33 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Known fused disconnects are subject to a number of problems in use. For example, any attempt to remove the fuse while the fuses are energized and under load may result in hazardous conditions because dangerous arcing may occur between the fuses and the fuse holder terminals. Some fuseholders designed to accommodate, for example, UL (Underwriters Laboratories) Class CC fuses and IEC (International Electrotechnical Commission) 10X38 fuses that are commonly used in industrial control devices include permanently mounted auxiliary contacts and associated rotary cams and switches to provide early-break and late-make voltage and current connections through the fuses when the fuses are pulled from fuse clips in a protective housing. One or more fuses may be pulled from the fuse clips, for example, by removing a drawer from the protective housing. Early-break and late-make connections are commonly employed, for example, in motor control applications. While early-break and late-make connections may increase the safety of such devices to users when installing and removing fuses, such features increase costs, complicate assembly of the fuseholder, and are undesirable for switching purposes. 
     Structurally, the early-break and late-make connections can be intricate and may not withstand repeated use for switching purposes. In addition, when opening and closing the drawer to disconnect or reconnect circuitry, the drawer may be inadvertently left in a partly opened or partly closed position. In either case, the fuses in the drawer may not be completely engaged to the fuse terminals, thereby compromising the electrical connection and rendering the fuseholder susceptible to unintended opening and closing of the circuit. Especially in environments subject to vibration, the fuses may be jarred loose from the clips. Still further, a partially opened drawer protruding from the fuseholder may interfere with workspace around the fuseholder. Workers may unintentionally bump into the opened drawers, and perhaps unintentionally close the drawer and re-energize the circuit. 
     Additionally, in certain systems, such as industrial control devices, electrical equipment has become standardized in size and shape, and because known fused disconnect switches tend to vary in size and shape from the standard norms, they are not necessarily compatible with power distribution panels utilized with such equipment. For at least the above reasons, use of fused disconnect switches have not completely met the needs of certain end applications. 
       FIG. 1  is a perspective view of an exemplary fusible switching disconnect device  100  that overcomes the aforementioned difficulties. The fusible switching disconnect device  100  may be conveniently switched on and off in a convenient and safe manner without interfering with workspace around the device  100 . The disconnect device  100  may reliably switch a circuit on and off in a cost effective manner and may be used with standardized equipment in, for example, industrial control applications. Further, the disconnect device  100  may be provided with various mounting and connection options for versatility in the field. Various embodiments will be described below to demonstrate the versatility of the disconnect device, and it is contemplated that the disconnect device  100  may be beneficial in a variety of electrical circuits and applications. The embodiments set forth below are therefore provided for illustrative purposes only, and the invention is not intended to be limited to any specific embodiment or to any specific application. 
     In the illustrative embodiment of  FIG. 1 , the disconnect device  100  may be a two pole device formed from two separate disconnect modules  102 . Each module  102  may include an insulative housing  104 , a fuse  106  loaded into the housing  104 , a fuse cover or cap  108  attaching the fuse to the housing  104 , and a switch actuator  110 . The modules  102  are single pole modules, and the modules  102  may be coupled or ganged together to form the two pole disconnect device  100 . It is contemplated, however, that a multi-pole device could be formed in a single housing rather than in the modular fashion of the exemplary embodiment shown in  FIG. 1 . 
     The housing  104  may be fabricated from an insulative or nonconductive material, such as plastic, according to known methods and techniques, including but not limited to injection molding techniques. In an exemplary embodiment, the housing  104  is formed into a generally rectangular size and shape which is complementary to and compatible with DIN and IEC standards applicable to standardized electrical equipment. In particular, for example, each housing  104  has lower edge  112 , opposite side edges  114 , side panels  116  extending between the side edges  114 , and an upper surface  118  extending between the side edges  114  and the side panels  116 . The lower edge  112  has a length L and the side edges  114  have a thickness T, such as 17.5 mm in one embodiment, and the length L and thickness T define an area or footprint on the lower edge  112  of the housing  104 . The footprint allows the lower edge  112  to be inserted into a standardized opening having a complementary shape and dimension. Additionally, the side edges  114  of the housing  104  have a height H in accordance with known standards, and the side edges  114  include slots  120  extending therethrough for ventilating the housing  104 . The upper surface  118  of the housing  104  may be contoured to include a raised central portion  122  and recessed end portions  124  extending to the side edges  114  of the housing  104 . 
     The fuse  106  of each module  102  may be loaded vertically in the housing  104  through an opening in the upper surface  118  of the housing  104 , and the fuse  106  may extend partly through the raised central portion  122  of the upper surface  118 . The fuse cover  108  extends over the exposed portion of the fuse  106  extending from the housing  104 , and the cover  108  secures the fuse  106  to the housing  104  in each module  102 . In an exemplary embodiment, the cover  108  may be fabricated from a non-conductive material, such as plastic, and may be formed with a generally flat or planar end section  126  and elongated fingers  128  extending between the upper surface  118  of the raised central portion  122  of the housing  104  and the end of the fuse  106 . Openings are provided in between adjacent fingers  128  to ventilate the end of the fuse  106 . 
     In an exemplary embodiment, the cover  108  further includes rim sections  130  joining the fingers  128  opposite the end section  126  of the cover  108 , and the rim sections  130  secure the cover  108  to the housing  104 . In an exemplary embodiment, the rim sections  130  cooperate with grooves in the housing  104  such that the cover  108  may rotate a predetermined amount, such as 25 degrees, between a locked position and a release position. That is, once the fuse  106  is inserted into the housing  104 , the fuse cover  108  may be installed over the end of the fuse  106  into the groove of the housing  104 , and the cover  108  may be rotated 25 degrees to the locked position wherein the cover  108  will frustrate removal of the fuse  106  from the housing  104 . The groove may also be ramped or inclined such that the cover  108  applies a slight downward force on the fuse  106  as the cover  108  is installed. To remove the fuse  106 , the cover  108  may be rotated from the locked position to the open position wherein both the cover  108  and the fuse  106  may be removed from the housing  104 . 
     The switch actuator  110  may be located in an aperture  132  of the raised upper surface  122  of the housing  104 , and the switch actuator  110  may partly extend through the raised upper surface  122  of the housing  104 . The switch actuator  100  may be rotatably mounted to the housing  104  on a shaft or axle  134  within the housing  104 , and the switch actuator  110  may include a lever, handle or bar  136  extending radially from the actuator  110 . By moving the lever  136  from a first edge  138  to a second edge  140  of the aperture  132 , the shaft  134  rotates to an open or switch position and electrically disconnects the fuse  106  in each module  102  as explained below. When the lever  136  is moved from the second edge  140  to the first edge  138 , the shaft  134  rotates back to the closed position illustrated in  FIG. 1  and electrically connects the fuse  106 . 
     A line side terminal element may  142  extend from the lower edge  112  of the housing  104  in each module  102  for establishing line and load connections to circuitry. As shown in  FIG. 1 , the line side terminal element  142  is a bus bar clip configured or adapted to connect to a line input bus, although it is contemplated that other line side terminal elements could be employed in alternative embodiments. A panel mount clip  144  also extends from the lower edge  112  of the housing  104  to facilitate mounting of the disconnect device  100  on a panel. 
       FIG. 2  is a side elevational view of one of the disconnect modules  102  shown in  FIG. 1  with the side panel  116  removed. The fuse  106  may be seen situated in a compartment  150  inside the housing  104 . In an exemplary embodiment, the fuse  106  may be a cylindrical cartridge fuse including an insulative cylindrical body  152 , conductive ferrules or end caps  154  coupled to each end of the body  152 , and a fuse element or fuse element assembly extending within the body  152  and electrically connected to the end caps  154 . In exemplary embodiments, the fuse  106  may be a UL Class CC fuse, a UL supplemental fuse, or an IEC 10X38 fuses which are commonly used in industrial control applications. These and other types of cartridge fuses suitable for use in the module  102  are commercially available from Cooper/Bussmann of St. Louis, Mo. It is understood that other types of fuses may also be used in the module  102  as desired. 
     A lower conductive fuse terminal  156  may be located in a bottom portion of the fuse compartment  150  and may be U-shaped in one embodiment. One of the end caps  154  of the fuse  106  rests upon an upper leg  158  of the lower terminal  156 , and the other end cap  154  of the fuse  106  is coupled to an upper terminal  160  located in the housing  104  adjacent the fuse compartment  150 . The upper terminal  160  is, in turn, connected to a load side terminal  162  to accept a load side connection to the disconnect module  102  in a known manner. The load side terminal  162  in one embodiment is a known saddle screw terminal, although it is appreciated that other types of terminals could be employed for load side connections to the module  102 . Additionally, the lower fuse terminal  156  may include fuse rejection features in a further embodiment which prevent installation of incorrect fuse types into the module  102 . 
     The switch actuator  110  may be located in an actuator compartment  164  within the housing  104  and may include the shaft  134 , a rounded body  166  extending generally radially from the shaft  134 , the lever  136  extending from the body  166 , and an actuator link  168  coupled to the actuator body  166 . The actuator link  168  may be connected to a spring loaded contact assembly  170  including first and second movable or switchable contacts  172  and  174  coupled to a sliding bar  176 . In the closed position illustrated in  FIG. 2 , the switchable contacts  172  and  174  are mechanically and electrically engaged to stationary contacts  178  and  180  mounted in the housing  104 . One of the stationary contacts  178  may be mounted to an end of the terminal element  142 , and the other of the stationary contacts  180  may be mounted to an end of the lower fuse terminal  156 . When the switchable contacts  172  and  174  are engaged to the stationary contacts  178  and  180 , a circuit is path completed through the fuse  106  from the line terminal  142  and the lower fuse terminal  156  to the upper fuse terminal  160  and the load terminal  162 . 
     While in an exemplary embodiment the stationary contact  178  is mounted to a terminal  142  having a bus bar clip, another terminal element, such as a known box lug or clamp terminal could be provided in a compartment  182  in the housing  104  in lieu of the bus bar clip. Thus, the module  102  may be used with a hard-wired connection to line-side circuitry instead of a line input bus. Thus, the module  102  is readily convertible to different mounting options in the field. 
     When the switch actuator  110  is rotated about the shaft  134  in the direction of arrow A, the siding bar  176  may be moved linearly upward in the direction of arrow B to disengage the switchable contacts  172  and  174  from the stationary contacts  178  and  180 . The lower fuse terminal  156  is then disconnected from the line-side terminal element while the fuse  106  remains electrically connected to the lower fuse terminal  156  and to the load side terminal  162 . An arc chute compartment  184  may be formed in the housing  104  beneath the switchable contacts  172  and  174 , and the arc chute may provide a space to contain and dissipate arcing energy as the switchable contacts  172  and  174  are disconnected. Arcing is broken at two locations at each of the contacts  172  and  174 , thus reducing arc intensity, and arcing is contained within the lower portions of the housing  104  and away from the upper surface  118  and the hands of a user when manipulating the switch actuator  110  to disconnect the fuse  106  from the line side terminal  142 . 
     The housing  104  additionally may include a locking ring  186  which may be used cooperatively with a retention aperture  188  in the switch actuator body  166  to secure the switch actuator  110  in one of the closed position shown in  FIG. 2  and the open position shown in  FIG. 3 . A locking pin for example, may be inserted through the locking ring  186  and the retention aperture  188  to restrain the switch actuator in the corresponding open or closed position. Additionally, a fuse retaining arm could be provided in the switch actuator  110  to prevent removal of the fuses except when the switch actuator  110  is in the open position. 
       FIG. 3  illustrates the disconnect module  102  after the switch actuator has been moved in the direction of Arrow A to an open or switched position to disconnect the switchable contacts  172  and  174  from the stationary contacts  178  and  180 . As the actuator is moved to the open position, the actuator body  166  rotates about the shaft  134  and the actuator link  168  is accordingly moved upward in the actuator compartment  164 . As the link  168  moves upward, the link  168  pulls the sliding bar  176  upward in the direction of arrow B to separate the switchable contacts  172  and  174  from the stationary contacts  178  and  180 . 
     A bias element  200  may be provided beneath the sliding bar  176  and may force the sliding bar  176  upward in the direction of arrow B to a fully opened position separating the contacts  172 ,  174  and  178 ,  180  from one another. Thus, as the actuator body  166  is rotated in the direction of arrow A, the link  168  is moved past a point of equilibrium and the bias element  200  assists in opening of the contacts  172 ,  174  and  178 ,  180 . The bias element  200  therefore prevents partial opening of the contacts  172 ,  174  and  178 ,  180  and ensures a full separation of the contacts to securely break the circuit through the module  102 . 
     Additionally, when the actuator lever  136  is pulled back in the direction of arrow C to the closed position shown in  FIG. 2 , the actuator link  168  is moved to position the sliding bar  176  downward in the direction of arrow D to engage and close the contacts  172 ,  174  and  178 ,  180  and reconnect the circuit through the fuse  106 . The sliding bar  176  is moved downward against the bias of the bias element  200 , and once in the closed position, the sliding bar  176 , the actuator link  168  and the switch actuator are in static equilibrium so that the switch actuator  110  will remain in the closed position. 
     In one exemplary embodiment, and as illustrated in  FIGS. 2 and 3 , the bias element  200  may be a helical spring element which is loaded in compression in the closed position of the switch actuator  110 . It is appreciated, however, that in an alternatively embodiment a coil spring could be loaded in tension when the switch actuator  110  is closed. Additionally, other known bias elements could be provided to produce opening and/or closing forces to assist in proper operation of the disconnect module  102 . Bias elements may also be utilized for dampening purposes when the contacts are opened. 
     The lever  136 , when moved between the opened and closed positions of the switch actuator, does not interfere with workspace around the disconnect module  102 , and the lever  136  is unlikely to be inadvertently returned to the closed position from the open position. In the closed position shown in  FIG. 3 , the lever  136  is located adjacent to an end of the fuse  106 . The fuse  106  therefore partly shelters the lever  136  from inadvertent contact and unintentional actuation to the closed position. The bias element  200  further provides some resistance to movement of the lever  136  and closing of the contact mechanism. Additionally, the stationary contacts  178  and  180  are at all times protected by the housing  104  of the module  102 , and any risk of electrical shock due to contact with line side terminal  142  and the stationary contacts  178  and  180  is avoided. The disconnect module  102  is therefore considered to be safer than many known fused disconnect devices. 
     When the modules  102  are ganged together to form a multi-pole device, such as the device  100 , one lever  136  may be extended through and connect to multiple switch actuators  110  for different modules. Thus, all the connected modules  102  may be disconnected and reconnected by manipulating a single lever  136 . That is, multiple poles in the device  100  may be switched simultaneously. Alternatively, the switch actuators  110  of each module  102  in the device  100  may be actuated independently with separate levers  136  for each module. 
       FIG. 4  is a side elevational view of a further exemplary embodiment of a fusible switching disconnect  102  including, for example, a retractable lockout tab  210  which may extend from the switch actuator  110  when the lever  136  is moved to the open position. The lockout tab  210  may be provided with a lock opening  212  therethrough, and a padlock or other element may be inserted through the lock opening  212  to ensure that the lever  136  may not be moved to the closed position. In different embodiments, the lockout tab  210  may be spring loaded and extended automatically, or may be manually extended from the switch actuator body  166 . When the lever  136  is moved to closed position, the lockout tab  210  may be automatically or manually returned to retracted position wherein the switch actuator  110  may be rotated back to the closed position shown in  FIG. 2 . 
       FIG. 5  is a perspective view of a third exemplary embodiment of a fusible switching disconnect module  220  similar to the module  102  described above but having, for example, a DIN rail mounting slot  222  formed in a lower edge  224  of a housing  226 . The housing  226  may also include openings  228  which may be used to gang the module  220  to other disconnect modules. Side edges  230  of the housing  226  may include connection openings  232  for line side and load connections to box lugs or clamps within the housing  226 . Access openings  234  may be provided in recessed upper surfaces  236  of the housing  226 . A stripped wire, for example, may be extended through the connection openings  232  and a screwdriver may be inserted through the access openings  234  to connect line and load circuitry to the module  220 . 
     Like the module  102 , the module  220  may include the fuse  106 , the fuse cover  108  and the switch actuator  110 . Switching of the module is accomplished with switchable contacts as described above in relation to the module  102 . 
       FIGS. 6 and 7  are perspective views of a fourth exemplary embodiment of a fusible switching disconnect module  250  which, like the modules  102  and  220  described above, includes a switch actuator  110  rotatably mounted to the housing on a shaft  134 , a lever  136  extending from the actuator link  168  and a slider bar  176 . The module  250  also includes, for example, a mounting clip  144  and a line side terminal element  142 . 
     Unlike the modules  102  and  220 , the module  250  may include a housing  252  configured or adapted to receive a rectangular fuse module  254  instead of a cartridge fuse  106 . The fuse module  254  is a known assembly including a rectangular housing  256 , and terminal blades  258  extending from the housing  256 . A fuse element or fuse assembly may be located within the housing  256  and is electrically connected between the terminal blades  258 . Such fuse modules  254  are known and in one embodiment are CubeFuse modules commercially available from Cooper/Bussmann of St. Louis, Mo. 
     A line side fuse clip  260  may be situated within the housing  252  and may receive one of the terminal blades  258  of the fuse module  254 . A load side fuse clip  262  may also be situated within the housing  252  and may receive the other of the fuse terminal blades  258 . The line side fuse clip  260  may be electrically connected to the stationary contact  180 . The load side fuse clip  262  may be electrically connected to the load side terminal  162 . The line side terminal  142  may include the stationary contact  178 , and switching may be accomplished by rotating the switch actuator  110  to engage and disengage the switchable contacts  172  and  174  with the respective stationary contacts  178  and  180  as described above. While the line terminal  142  is illustrated as a bus bar clip, it is recognized that other line terminals may be utilized in other embodiments, and the load side terminal  162  may likewise be another type of terminal in lieu of the illustrated saddle screw terminal in another embodiment. 
     The fuse module  254  may be plugged into the fuse clips  260 ,  262  or extracted therefrom to install or remove the fuse module  254  from the housing  252 . For switching purposes, however, the circuit is connected and disconnected at the contacts  172 ,  174  and  178  and  180  rather than at the fuse clips  260  and  262 . Arcing between the disconnected contacts may therefore contained in an arc chute or compartment  270  at the lower portion of the compartment and away from the fuse clips  260  and  262 . By opening the disconnect module  250  with the switch actuator  110  before installing or removing the fuse module  254 , any risk posed by electrical arcing or energized metal at the fuse and housing interface is eliminated. The disconnect module  250  is therefore believed to be safer to use than many known fused disconnect switches. 
     A plurality of modules  250  may be ganged or otherwise connected together to form a multi-pole device. The poles of the device could be actuated with a single lever  136  or independently operable with different levers. 
       FIG. 8  is a perspective view of a fifth exemplary embodiment of a fusible switching disconnect device  300  which is, for example, a multi-pole device in an integrated housing  302 . The housing  302  may be constructed to accommodate three fuses  106  in an exemplary embodiment, and is therefore well suited for a three phase power application. The housing  204  may include a DIN rail slot  304  in the illustrated embodiment, although it is understood that other mounting options, mechanisms, and mounting schemes may be utilized in alternative embodiments. Additionally, in one embodiment the housing  204  may have a width dimension D of about 45 mm in accordance with IEC industry standards for contactors, relays, manual motor protectors, and integral starters that are also commonly used in industrial control systems applications. The benefits of the invention, however, accrue equally to devices having different dimensions and devices for different applications. 
     The housing may also include connection openings  306  and access openings  308  in each side edge  310  which may receive a wire connection and a tool, respectively, to establish line and load connections to the fuses  106 . A single switch actuator  110  may be rotated to connect and disconnect the circuit through the fuses between line and load terminals of the disconnect device  300 . 
       FIG. 9  is a perspective view of an exemplary switching assembly  320  for the device  300 . The switching assembly may be accommodated in the housing  302  and in an exemplary embodiment may include a set of line terminals  322 , a set of load terminals  324 , a set of lower fuse terminals  326  associated with each respective fuse  106 , and a set of slider bars  176  having switchable contacts mounted thereon for engaging and disengaging stationary contacts mounted to the ends of the line terminals  322  and the lower fuse terminals  324 . An actuator link (not visible in  FIG. 9 ) may be mounted to an actuator shaft  134 , such that when the lever  136  is rotated, the slider bar  176  may be moved to disconnect the switchable contacts from the stationary contacts. Bias elements  200  may be provided beneath each of the slider bars  176  and assist operation of the switch actuator  110  as described above. As with the foregoing embodiments of modules, a variety of line side and load side terminal structures may be used in various embodiments of the switching assembly. 
     Retention bars  328  may also be provided on the shaft  134  which extend to the fuses  106  and engage the fuses in an interlocking manner to prevent the fuses  106  from being removed from the device  300  except when the switch actuator  110  is in the open position. In the open position, the retention bars  328  may be angled away from the fuses  106  and the fuses may be freely removed. In the closed position, as shown in  FIG. 9 , the retention arms or bars  328  lock the fuse in place. In an exemplary embodiment, distal ends of the bars or arms  328  may be received in slots or detents in the fuses  106 , although the fuses  106  could be locked in another manner as desired. 
       FIG. 10  is a perspective view of a sixth exemplary embodiment of a fusible switching disconnect device  370  including the disconnect module  300  described above and, for example, an under voltage module  372  mounted to one side of the module  300  and mechanically linked to the switch mechanism in the module  300 . In an exemplary embodiment, the under voltage module  372  may include an electromagnetic coil  374  calibrated to a predetermined voltage range. When the voltage drops below the range, the electromagnetic coil causes the switch contacts in the module  300  to open. A similar module  372  could be employed in an alternative embodiment to open the switch contacts when the voltage experienced by the electromagnetic exceeds a predetermined voltage range, and may therefore serve as an overvoltage module. In such a manner, the switch contact in the module  300  could be opened with module  372  and the coil  374  as undervoltage or overvoltage conditions occur. 
       FIG. 11  is a perspective view of a seventh exemplary embodiment of a fusible switching disconnect device  400  which is essentially the disconnect device  300  and a disconnect device  220  coupled together. The disconnect device  300  provides three poles for an AC power circuit and the device  220  provides an additional pole for other purposes. 
       FIG. 12  is a perspective view of an eighth embodiment of a fusible switching disconnect module  410  that, like the foregoing embodiments, includes a nonconductive housing  412 , a switch actuator  414  extending through a raised upper surface  415  of the housing  412 , and a cover  416  that provides access to a fuse receptacle (not shown in  FIG. 12 ) within the housing  412  for installation and replacement of an overcurrent protection fuse (also not shown in  FIG. 12 ). Like the foregoing embodiments, the housing  412  includes switchable and stationary contacts (not shown in  FIG. 12 ) that complete or break an electrical connection through the fuse in the housing  412  via movement of an actuator lever  417 . 
     A DIN rail mounting slot  418  may be formed in a lower edge  420  of the housing  412 , and the DIN rail mounting slot  418  may be dimensioned, for example, for snap-fit engagement and disengagement with a 35 mm DIN rail by hand and without a need of tools. The housing  412  may also include openings  422  that may be used to gang the module  410  to other disconnect modules as explained below. Side edges  424  of the housing  412  may be open ended to provide access to wire lug terminals  426  to establish line and load-side electrical connections external circuitry. Terminal access openings  428  may be provided in recessed upper surfaces  430  of the housing  412 . A stripped wire, for example, may be extended through the sides of the wire lug terminals  426  and a screwdriver may be inserted through the access openings  428  to tighten a terminal screw to clamp the wires to the terminals  426  and connect line and load circuitry to the module  410 . While wire lug terminals  426  are included in one embodiment, it is recognized that a variety of alternative terminal configurations or types may be utilized in other embodiments to establish line and load side electrical connections to the module  410  via wires, cables, bus bars etc. 
     Like the foregoing embodiments, the housing  412  is sized and dimensioned complementary to and compatible with DIN and IEC standards, and the housing  412  defines an area or footprint on the lower edge  420  for use with standardized openings having a complementary shape and dimension. By way of example only, the housing  412  of the single pole module  410  may have a thickness T of about 17.5 mm for a breaking capacity of up to 32 A; 26 mm for a breaking capacity of up to 50 A, 34 mm for a breaking capacity of up to 125 A; and 40 mm for a breaking capacity of up to 150 A per DIN Standard 43 880. Likewise, it is understood that the module  410  could be fabricated as a multiple pole device such as a three pole device having a dimension T of about 45 mm for a breaking capacity of up to 32 A; 55 mm for a breaking capacity of up to 50 A, and 75 mm for a breaking capacity of up to 125 A. While exemplary dimensions are provided, it is understood that other dimensions of greater or lesser values may likewise be employed in alternative embodiments of the invention. 
     Additionally, and as illustrated in  FIG. 12 , the side edges  424  of the housing  412  may include opposed pairs of vertically oriented flanges  432  spaced from one another and projecting away from the wire lug terminals  426  adjacent the housing upper surface  430  and the sides of the wire lug terminals  426 . The flanges  432 , sometimes referred to as wings, provide an increased surface area of the housing  412  in a horizontal plane extending between the between the wire lug terminals  426  on the opposing side edges  424  of the housing  412  than would otherwise occur if the flanges  432  were not present. That is, a peripheral outer surface area path length extending in a plane parallel to the lower surface  420  of the housing  412  includes the sum of the exterior surface dimensions of one of the pairs of flanges  432  extending from one of the terminals  426 , the exterior dimensions of the respective front or rear panel  431 ,  433  of the housing, and the exterior surface dimensions of the opposing flanges  432  extending to the opposite terminal  426 . 
     Additionally, the housing  412  may also include horizontally extending ribs or shelves  434  spaced from one another and interconnecting the innermost flanges  432  in a lower portion of the housing side edges  424 . The ribs or shelves  434  increase a surface area path length between the terminals  426  in a vertical plane of the housing  412  to meet external requirements for spacing between the terminals  426 . The flanges  432  and ribs  434  result in serpentine-shaped surface areas in horizontal and vertical planes of the housing  412  that permit greater voltage ratings of the device without increasing the footprint of the module  410  in comparison, for example, to the previously described embodiments of  FIGS. 1-11 . For example, the flanges  432  and the ribs  434 , facilitate a voltage rating of 600 VAC while meeting applicable internal and external spacing requirements between the terminals  426  under applicable UL standards. 
     The cover  416 , unlike the above-described embodiments, may include a substantially flat cover portion  436 , and an upstanding finger grip portion  438  projecting upwardly and outwardly from one end of the flat cover portion  436  and facing the switch actuator  414 . The cover may be fabricated from a nonconductive material or insulative material such as plastic according to known techniques, and a the flat cover portion  436  may be hinged at an end thereof opposite the finger grip portion  438  so that the cover portion  436  is pivotal about the hinge. By virtue of the hinge, the finger grip portion  438  is movable away from the switch actuator along an arcuate path as further explained below. As illustrated in  FIG. 12 , the cover  416  is in a closed position concealing the fuse within the housing  412 , and as explained below, the cover  416  is movable to an open position providing access to the fuse in the disconnect module  410 . 
       FIG. 13  is a side elevational view of the module  410  with the front panel  431  ( FIG. 12 ) removed so that internal components and features may be seen. The wire lug terminals  426  and terminal screws  440  are positioned adjacent the side edges  424  of the housing  412 . A fuse  442  is loaded or inserted into the module  410  in a direction substantially perpendicular to the housing upper surface  415 , and as illustrated in  FIG. 13 , a longitudinal axis  441  of the fuse  442  extends vertically, as opposed to horizontally, within the housing  412 . The fuse  442  is contained within the housing  412  beneath the cover  416 , and more specifically beneath the flat cover portion  436 . The fuse  442  is situated longitudinally in a fuse receptacle  437  integrally formed in the housing  412 . That is, the fuse receptacle  437  is not movable relative to the housing  412  for loading and unloading of the fuse  442 . The fuse  442  is received in the receptacle  437  with one end of the fuse  442  positioned adjacent and beneath the cover  416  and the module top surface  415  and the other end of the fuse  442  spaced from the cover  416  and the module top surface  415  by a distance equal to the length of the fuse  442 . An actuator interlock  443  is formed with the cover  416  and extends downwardly into the housing  412  adjacent and alongside the fuse receptacle  437 . The actuator interlock  443  of the cover  416  extends opposite and away from the cover finger grip portion  438 . 
     A cover lockout tab  444  extends radially outwardly from a cylindrical body  446  of the switch actuator  414 , and when the switch actuator  414  is in the closed position illustrated in  FIG. 13  completing an electrical connection through the fuse  442 , the cover lockout tab  444  is extended generally perpendicular to the actuator interlock  443  of the cover  416  and a distal end of the cover lockout tab  444  is positioned adjacent the actuator interlock  443  of the cover  416 . The cover lockout tab  444  therefore directly opposes movement of the actuator interlock  443  and resists any attempt by a user to rotate the cover  416  about the cover hinge  448  in the direction of arrow E to open the cover  416 . In such a manner, the fuse  442  cannot be accessed without first rotating the switch actuator  414  in the direction of arrow F to move the pair of switchable contacts  450  away from the stationary contacts  452  via the actuator link  454  and sliding bar  456  carrying the switchable contacts  450  in a similar manner to the foregoing embodiments. Inadvertent contact with energized portions of the fuse  442  is therefore prevented, as the cover  416  can only be opened to access the fuse  442  after the circuit through the fuse  442  is disconnected via the switchable contacts  450 , thereby providing a degree of safety to human operators of the module  410 . Additionally, and because the cover  416  conceals the fuse  442  when the switchable contacts  450  are closed, the outer surfaces of the housing  412  and the cover  416  are touch safe. 
     A conductive path through the housing  412  and fuse  442  is established as follows. A rigid terminal member  458  is extended from the load side terminal  426  closest to the fuse  442  on one side of the housing  412 . A flexible contact member  460 , such as a wire may be connected to the terminal member  458  at one end and attached to an inner surface of the cover  416  at the opposite end. When the cover  416  is closed, the contact member  460  is brought into mechanical and electrical engagement with an upper ferrule or end cap  462  of the fuse  442 . A movable lower fuse terminal  464  is mechanically and electrically connected to the lower fuse ferrule or end cap  466 , and a flexible contact member  468  interconnects the movable lower fuse terminal  464  to a stationary terminal  470  that carries one of the stationary contacts  452 . The switchable contacts  450  interconnect the stationary contacts  452  when the switch actuator  414  is closed as shown in  FIG. 13 . A rigid terminal member  472  completes the circuit path to the line side terminal  426  on the opposing side of the housing  412 . In use, current flows through the circuit path from the line side terminal  426  and the terminal member  472 , through the switchable contacts  450  and  452  to the terminal member  470 . From the terminal member  470 , current flows through the contact member  468  to the lower fuse terminal  464  and through the fuse  442 . After flowing through the fuse  442 , current flows to the contact member  460  to the terminal member  458  and to the line side terminal  426 . 
     The fuse  442  in different exemplary embodiments may be a commercially available 10x38 Midget fuse of Cooper/Bussmann of St. Louis, Mo.; an IEC 10x38 fuse; a class CC fuse; or a D/DO European style fuse. Additionally, and as desired, optional fuse rejection features may be formed in the lower fuse terminal  464  or elsewhere in the module, and cooperate with fuse rejection features of the fuses so that only certain types of fuses may be properly installed in the module  410 . While certain examples of fuses are herein described, it is understood that other types and configurations of fuses may also be employed in alternative embodiments, including but not limited to various types of cylindrical or cartridge fuses and rectangular fuse modules. 
     A biasing element  474  may be provided between the movable lower fuse terminal  464  and the stationary terminal  470 . The bias element  474  may be for example, a helical coil spring that is compressed to provide an upward biasing force in the direction of arrow G to ensure mechanical and electrical engagement of the movable lower fuse terminal  464  to the lower fuse ferrule  466  and mechanical and electrical engagement between the upper fuse ferrule  462  and the flexible contact member  460 . When the cover  416  is opened in the direction of arrow E to the open position, the bias element  474  forces the fuse upward along its axis  441  in the direction of arrow G as shown in  FIG. 14 , exposing the fuse  442  through the raised upper surface  415  of the housing  412  for easy retrieval by an operator for replacement. That is, the fuse  442 , by virtue of the bias element  474 , is automatically lifted and ejected from the housing  412  when the cover  416  is rotated about the hinge  448  in the direction of arrow E after the switch actuator  414  is rotated in the direction of arrow F. 
       FIG. 15  is a side elevational view of the module  410  with the cover  416  pivoted about the hinge  448  and the switch actuator  414  in the open position. The switchable contacts  450  are moved upwardly by rotation of the actuator  414  and the displacement of the actuator link  454  causes the sliding bar  456  to move along a linear axis  475  substantially parallel to the axis  441  of the fuse  442 , physically separating the switchable contacts  450  from the stationary contacts  452  within the housing  412  and disconnecting the conductive path through the fuse  442 . Additionally, and because of the pair of switchable contacts  450 , electrical arcing is distributed among more than one location as described above. 
     The bias element  474  deflects when the cover  416  is opened after the actuator  414  is moved to the open position, and the bias element  474  lifts the fuse  442  from the housing  412  so that the upper fuse ferrule  462  is extended above the top surface  415  of the housing. In such a position, the fuse  442  may be easily grasped and pulled out of or extracted from the module  410  along the axis  441 . Fuses may therefore be easily removed from the module  410  for replacement. 
     Also when the actuator  414  is moved to the open position, an actuator lockout tab  476  extends radially outwardly from the switch actuator body  446  and may accept for example, a padlock to prevent inadvertent closure of the actuator  414  in the direction of arrow H that would otherwise cause the slider bar  456  to move downward in the direction of arrow I along the axis  475  and engage the switchable contacts  450  to the stationary contacts  452 , again completing the electrical connection to the fuse  442  and presenting a safety hazard to operators. When desired, the cover  416  may be rotated back about the hinge  448  to the closed position shown in  FIGS. 12 and 13 , and the switch actuator  414  may be rotated in the direction of arrow H to move the cover interlock tab  444  into engagement with the actuator interlock  443  of the cover  416  to maintain each of the cover  416  and the actuator  414  in static equilibrium in a closed and locked position. Closure of the cover  416  requires some force to overcome the resistance of the bias spring  474  in the fuse receptacle  437 , and movement of the actuator to the closed position requires some force to overcome the resistance of a bias element  478  associated with the sliding bar  456 , making inadvertent closure of the contacts and completion of the circuit through the module  410  much less likely. 
       FIG. 16  is a perspective view of a ganged arrangement of fusible switching disconnect modules  410 . Connector pieces  480  may be fabricated from plastic, for example, and may be used with the openings  422  in the housing panels to retain modules  410  in a side-by-side relation to one another with, for example, snap fit engagement. Pins  482  and/or shims  484 , for example, may be utilized to join or tie the actuator levers  417  and cover finger grip portions  438  of each module  410  to one another so that all of the actuator levers  417  and/or of all of the covers  416  of the combined modules  410  are simultaneously moved with one another. Simultaneous movement of the covers  416  and levers  417  may be especially advantageous for breaking three phase current or, as another example, when switching power to related equipment, such as motor and a cooling fan for the motor so that one does not run without the other. 
     While single pole modules  410  ganged to one another to form multiple pole devices has been described, it is understood that a multiple pole device having the features of the module  410  could be constructed in a single housing with appropriate modification of the embodiment shown in  FIGS. 8 and 9 , for example. 
       FIG. 17  is a perspective view of a ninth embodiment of a fusible switching disconnect module  500  that, like the foregoing embodiments, includes a single pole housing  502 , a switch actuator  504  extending through a raised upper surface  506  of the housing  502 , and a cover  508  that provides access to a fuse receptacle (not shown in  FIG. 17 ) within the housing  502  for installation and replacement of an overcurrent protection fuse (also not shown in  FIG. 17 ). Like the foregoing embodiments, the housing  502  includes switchable and stationary contacts (not shown in  FIG. 17 ) that connect or disconnect an electrical connection through the fuse in the housing  502  via movement of an actuator lever  510 . 
     Similar to the module  410 , the module  500  may include a DIN rail mounting slot  512  formed in a lower edge  514  of the housing  502  for mounting of the housing  502  without a need of tools. The housing  502  may also include an actuator opening  515  providing access to the body of the switch actuator  504  so that the actuator  504  may be rotated between the open and closed positions in an automated manner and facilitate remote control of the module  500 . Openings  516  are also provided that may be used to gang the module  500  to other disconnect modules. A curved or arcuate tripping guide slot  517  is also formed in a front panel of the housing  502 . A slidable tripping mechanism, described below, is selectively positionable within the slot  517  to trip the module  500  and disconnect the current path therethrough upon an occurrence of predetermined circuit conditions. The slot  517  also provides access to the tripping mechanism for manual tripping of the mechanism with a tool, or to facilitate remote tripping capability. 
     Side edges  518  of the housing  502  may be open ended to provide access to line and load side wire lug terminals  520  to establish line and load-side electrical connections to the module  500 , although it is understood that other types of terminals may be used. Terminal access openings  522  may be provided in recessed upper surfaces  524  of the housing  502  to receive a stripped wire or other conductor extended through the sides of the wire lug terminals  520 , and a screwdriver may be inserted through the access openings  522  to connect line and load circuitry to the module  500 . Like the foregoing embodiments, the housing  502  is sized and dimensioned complementary to and compatible with DIN and IEC standards, and the housing  502  defines an area or footprint on the lower surface  514  of the housing for use with standardized openings having a complementary shape and dimension. 
     Like the module  410  described above, the side edges  518  of the housing  502  may include opposed pairs of vertically oriented flanges or wings  526  spaced from one another and projecting away from the wire lug terminals  520  adjacent the housing upper surface  524  and the sides of the wire lug terminals  520 . The housing  502  may also include horizontally extending ribs or shelves  528  spaced from one another and interconnecting the innermost flanges  526  in a lower portion of the housing side edges  518 . The flanges  526  and ribs  528  result in serpentine-shaped surface areas in horizontal and vertical planes of the housing  502  that permit greater voltage ratings of the device without increasing the footprint of the module  500  as explained above. 
     The cover  508 , unlike the above-described embodiments, may include a contoured outer surface defining a peak  530  and a concave section  532  sloping downwardly from the peak  530  and facing the switch actuator  504 . The peak  530  and the concave section  532  form a finger cradle area on the surface of the cover  508  and is suitable for example, to serve as a thumb rest for an operator to open or close the cover  508 . The cover  508  may be hinged at an end thereof closest to the peak  530  so that the cover  508  is pivotal about the hinge and the cover  508  is movable away from the switch actuator  504  along an arcuate path. As illustrated in  FIG. 17 , the cover  508  is in a closed touch safe position concealing the fuse within the housing  502 , and as explained below, the cover  508  is movable to an open position providing access to the fuse. 
       FIG. 18  is a side elevational view of a portion of the fusible switching disconnect module  500  with a front panel thereof removed so that internal components and features may be seen. In some aspects the module  500  is similar to the module  410  described above in its internal components, and for brevity like features of the modules  500  and  410  are indicated with like reference characters in  FIG. 18 . 
     The wire lug terminals  520  and terminal screws  440  are positioned adjacent the side edges  518  of the housing  502 . The fuse  442  is vertically loaded into the housing  502  beneath the cover  508 , and the fuse  442  is situated in the non-movable fuse receptacle  437  formed in the housing  502 . The cover  508  may be formed with a conductive contact member that may be, for example, cup-shaped to receive the upper fuse ferrule  462  when the cover  5508  is closed. 
     A conductive circuit path is established from the line side terminal  520  and the terminal member  472 , through the switch contacts  450  and  452  to the terminal member  470 . From the terminal member  470 , current flows through the contact member  468  to the lower fuse terminal  464  and through the fuse  442 . After flowing through the fuse  442 , current flows from the conductive contact member  542  of the cover  508  to the contact member  460  connected to the conductive contact member  542 , and from the contact member  460  to the terminal member  458  and to the line side terminal  426 . 
     A biasing element  474  may be provided between the movable lower fuse terminal  464  and the stationary terminal  470  as described above to ensure mechanical and electrical connection between the cover contact member  542  and the upper fuse ferrule  462  and between the lower fuse terminal  464  and the lower fuse ferrule  466 . Also, the bias element  474  automatically ejects the fuse  442  from the housing  502  as described above when the cover  508  is rotated about the hinge  448  in the direction of arrow E after the switch actuator  504  is rotated in the direction of arrow F. 
     Unlike the module  410 , the module  500  may further include a tripping mechanism  544  in the form of a slidably mounted trip bar  545  and a solenoid  546  connected in parallel across the fuse  442 . The trip bar  545  is slidably mounted to the tripping guide slot  517  formed in the housing  502 , and in an exemplary embodiment the trip bar  545  may include a solenoid arm  547 , a cover interlock arm  548  extending substantially perpendicular to the solenoid arm  547 , and a support arm  550  extending obliquely to each of the solenoid arm  547  and cover interlock arm  548 . The support arm  550  may include a latch tab  552  on a distal end thereof. The body  446  of the switch actuator  504  may be formed with a ledge  554  that cooperates with the latch tab  552  to maintain the trip bar  545  and the actuator  504  in static equilibrium with the solenoid arm  547  resting on an upper surface of the solenoid  546 . 
     A torsion spring  555  is connected to the housing  502  one end and the actuator body  446  on the other end, and the torsion spring  555  biases the switch actuator  504  in the direction of arrow F to the open position. That is, the torsion spring  555  is resistant to movement of the actuator  504  in the direction of arrow H and tends to force the actuator body  446  to rotate in the direction of arrow F to the open position. Thus, the actuator  504  is failsafe by virtue of the torsion spring  555 . If the switch actuator  504  is not completely closed, the torsion spring  555  will force it to the open position and prevent inadvertent closure of the actuator switchable contacts  450 , together with safety and reliability issues associated with incomplete closure of the switchable contacts  450  relative to the stationary contacts  452 . 
     In normal operating conditions when the actuator  504  is in the closed position, the tendency of the torsion spring  555  to move the actuator to the open position is counteracted by the support arm  550  of the trip bar  545  as shown in  FIG. 18 . The latch tab  552  of the support arm  550  engages the ledge  554  of the actuator body  446  and holds the actuator  504  stably in static equilibrium in a closed and locked position. Once the latch tab  552  is released from the ledge  554  of the actuator body  446 , however, the torsion spring  555  forces the actuator  504  to the open position. 
     An actuator interlock  556  is formed with the cover  508  and extends downwardly into the housing  502  adjacent the fuse receptacle  437 . The cover interlock arm  548  of the trip arm  545  is received in the actuator interlock  556  of the cover  508  and prevents the cover  508  from being opened unless the switch actuator  504  is rotated in the direction of arrow F as explained below to move the trip bar  545  and release the cover interlock arm  548  of the trip bar  545  from the actuator interlock  556  of the cover  508 . Deliberate rotation of the actuator  504  in the direction of arrow F causes the latch tab  552  of the solenoid arm  550  of the trip bar  545  to be pivoted away from the actuator and causes the solenoid arm  547  to become inclined or angled relative to the solenoid  546 . Inclination of the trip bar  545  results in an unstable position and the torsion spring  555  forces the actuator  504  to rotate and further pivot the trip bar  545  to the point of release. 
     Absent deliberate movement of the actuator to the open position in the direction of arrow F, the trip bar  545 , via the interlock arm  548 , directly opposes movement of the cover  508  and resists any attempt by a user to rotate the cover  508  about the cover hinge  448  in the direction of arrow E to open the cover  508  while the switch actuator  504  is closed and the switchable contacts  450  are engaged to the stationary contacts  452  to complete a circuit path through the fuse  442 . Inadvertent contact with energized portions of the fuse  442  is therefore prevented, as the fuse can only be accessed when the circuit through the fuse is broken via the switchable contacts  450 , thereby providing a degree of safety to human operators of the module  500 . 
     Upper and lower solenoid contact members  557 ,  558  are provided and establish electrical contact with the respective upper and lower ferrules  462 ,  466  of the fuse  442  when the cover  508  is closed over the fuse  442 . The contact members  557 ,  558  establish, in turn, electrical contact to a circuit board  560 . Resistors  562  are connected to the circuit board  560  and define a high resistance parallel circuit path across the ferrules  462 ,  466  of the fuse  442 , and the solenoid  546  is connected to this parallel circuit path on the circuit board  560 . In an exemplary embodiment, the resistance is selected so that, in normal operation, substantially all of the current flow passes through the fuse  442  between the fuse ferrules  462 ,  466  instead of through the upper and lower solenoid contact members  557 ,  558  and the circuit board  560 . The coil of the solenoid  546  is calibrated so that when the solenoid  546  experiences a predetermined voltage, the solenoid generates an upward force in the direction of arrow G that causes the trip bar  545  to be displaced in the tripping guide slot  517  along an arcuate path defined by the slot  517 . 
     As those in the art may appreciate, the coil of the solenoid  546  may be calibrated to be responsive to a predetermined undervoltage condition or a predetermined overvoltage condition as desired. Additionally, the circuit board  560  may include circuitry to actively control operation of the solenoid  546  in response to circuit conditions. Contacts may further be provided on the circuit board  560  to facilitate remote control tripping of the solenoid  546 . Thus, in response to abnormal circuit conditions that are predetermined by the calibration of the solenoid coil or control circuitry on the board  560 , the solenoid  546  activates to displace the trip bar  545 . Depending on the configuration of the solenoid  546  and/or the board  560 , opening of the fuse  442  may or may not trigger an abnormal circuit condition causing the solenoid  546  to activate and displace the trip bar  545 . 
     As the trip bar  545  traverses the arcuate path in the guide slot  517  when the solenoid  546  operates, the solenoid arm  547  is pivoted and becomes inclined or angled relative to the solenoid  546 . Inclination of the solenoid arm  547  causes the trip bar  545  to become unstable and susceptible to force of the torsion spring  555  acting on the trip arm latch tab  552  via the ledge  554  in the actuator body  446 . As the torsion spring  555  begins to rotate the actuator  504 , the trip bar  545  is further pivoted due to engagement of the trip arm latch tab  552  and the actuator ledge  554  and becomes even more unstable and subject to the force of the torsion spring. The trip bar  545  is further moved and pivoted by the combined action of the guide slot  517  and the actuator  504  until the trip arm latch tab  552  is released from the actuator ledge  554 , and the interlock arm  548  of the trip bar  545  is released from the actuator interlock  556 . At this point, each of the actuator  504  and the cover  508  are freely rotatable. 
       FIG. 19  is a side elevational view of the fusible switching disconnect module  500  illustrating the solenoid  546  in a tripped position wherein a solenoid plunger  570  is displaced upwardly and engages the trip bar  545 , causing the trip bar  545  to move along the curved guide slot  517  and become inclined and unstable relative to the plunger. As the trip bar  545  is displaced and pivoted to become unstable, the torsion spring  555  assists in causing the trip bar  545  to become more unstable as described above, until the ledge  554  of the actuator body  446  is released from the latch tab  552  of the trip bar  545 , and the torsion spring  555  forces the actuator  504  to rotate completely to the open position shown in  FIG. 19 . As the actuator  504  rotates to the open position, the actuator link  454  pulls the sliding bar  456  upward along the linear axis  475  and separates the switchable contacts  450  from the stationary contacts  452  to open or disconnect the circuit path between the housing terminals  520 . Additionally, the pivoting of the trip bar  545  releases the actuator interlock  556  of the cover  508 , allowing the bias element  474  to force the fuse upwardly from the housing  502  and causing the cover  508  to pivot about the hinge  448  so that the fuse  442  is exposed for easy removal and replacement. 
       FIG. 20  is a perspective view of the fusible switching disconnect module  500  in the tripped position and the relative positions of the actuator  504 , the trip bar  545  and the cover  508 . As also shown in  FIG. 20 , the sliding bar  456  carrying the switchable contacts  450  may be assisted to the open position by a first bias element  572  external to the sliding bar  456  and a second bias element  574  internal to the sliding bar  456 . The bias elements  572 ,  574  may be axially aligned with one another but oppositely loaded in one embodiment. The bias elements  572 ,  574  may be for example, helical coil spring elements, and the first bias element  572  may be loaded in compression, for example, while the second bias element  574  is loaded in tension. Therefore, the first bias element  572  exerts an upwardly directed pushing force on the sliding bar  456  while the second bias element  574  exerts an upwardly directed pulling force on the sliding bar  456 . The combined forces of the bias elements  572 ,  574  force the sliding bar in an upward direction indicated by arrow G when the actuator is rotated to the open position as shown in  FIG. 20 . The double spring action of the bias elements  572 ,  574 , together with the torsion spring  555  ( FIGS. 18 and 19 ) acting on the actuator  504  ensures a rapid, automatic, and complete separation of the switchable contacts  450  from the fixed contacts  452  in a reliable manner. Additionally, the double spring action of the bias elements  572 ,  574  effectively prevents and/or compensates for contact bounce when the module  500  is operated. 
     As  FIG. 20  also illustrates, the actuator interlock  556  of the cover  508  is substantially U-shaped in an exemplary embodiment. As seen in  FIG. 21  the interlock  556  extends downwardly into the housing  502  when the cover  508  is in the closed position over the fuse  442 , loading the bias element  474  in compression.  FIG. 22  illustrates the cover interlock arm  548  of the trip bar  545  aligned with the actuator interlock  556  of the cover  508  when the cover  508  is in the closed position. In such a position, the actuator  504  may be rotated back in the direction of arrow H to move the sliding bar  456  downward in the direction of arrow I to engage the switchable contacts  450  to the stationary contacts  452  of the housing  502 . As the actuator  504  is rotated in the direction of arrow H, the trip bar  545  is pivoted back to the position shown in  FIG. 18 , stably maintaining the actuator  504  in the closed position in an interlocked arrangement with the cover  508 . The trip bar  545  may be spring loaded to further assist the tripping action of the module  500  and/or the return of the trip bar  545  to the stable position, or still further to bias the trip bar  545  to a predetermined position with respect to the tripping guide slot  517 . 
       FIGS. 23 and 24  illustrate a tenth embodiment of a fusible switching disconnect device  600  including a disconnect module  500  and an auxiliary contact module  602  coupled or ganged to the housing  502  in a side-by-side relation to the module  500  via the openings  516  ( FIG. 17 ) in the module  500 . 
     The auxiliary contact module  602  may include a housing  603  generally complementary in shape to the housing  502  of the module  500 , and may include an actuator  604  similar to the actuator  504  of the module  500 . An actuator link  606  may interconnect the actuator  604  and a sliding bar  608 . The sliding bar  608  may carry, for example, two pairs of switchable contacts  610  spaced from another. One of the pairs of switchable contacts  610  connects and disconnects a circuit path between a first set of auxiliary terminals  612  and rigid terminal members  614  extending from the respective terminals  612  and each carrying a respective stationary contact for engagement and disengagement with the first set of switchable contacts  610 . The other pair of switchable contacts  610  connects and disconnects a circuit path between a second set of auxiliary terminals  616  and rigid terminal members  618  extending from the respective terminals  616  and each carrying a respective stationary contact for engagement and disengagement with the second set of switchable contacts  610 . 
     By joining or tying the actuator lever  620  of the auxiliary contact module  602  to the actuator lever  510  of the disconnect module  500  with a pin or a shim, for example, the actuator  604  of the auxiliary contact module  602  may be moved or tripped simultaneously with the actuator  504  of the disconnect module  500 . Thus, auxiliary connections may be connected and disconnected together with a primary connection established through the disconnect module  500 . For example, when the primary connection established through the module  500  powers an electric motor, an auxiliary connection to a cooling fan may be made to the auxiliary contact module via one of the sets of terminals  612  and  616  so that the fan and motor will be powered on and off simultaneously by the device  600 . As another example, one of the auxiliary connections through the terminals  612  and  616  of the auxiliary contact module  602  may be used for remote indication purposes to signal a remote device of the status of the device as being opened or closed to connect or disconnect circuits through the device  600 . 
     While the auxiliary contact features have been described in the context of an add-on module  602 , it is understood that the components of the module  602  could be integrated into the module  500  if desired. Single pole or multiple pole versions of such a device could likewise be provided. 
       FIGS. 25-27  illustrate an eleventh embodiment of a fusible switching disconnect device  650  including a disconnect module  500  and a monitoring module  652  coupled or ganged to the housing  502  of the module  500  via the openings  516  ( FIG. 17 ) in the module  500 . 
     The monitoring module  652  may include a housing  654  generally complementary in shape to the housing  502  of the module  500 . A sensor board  656  is located in the housing  652 , and flexible contact members  658 ,  660  are respectively connected to each of the ferrules  462 ,  466  ( FIG. 18 ) of the fuse  442  ( FIG. 1 ) in the disconnect module  500  via, for example, the upper and lower solenoid contact members  557 ,  568  ( FIG. 18 ) that establish a parallel circuit path across the fuse ferrules  462 ,  466 . The sensor board  656  includes a sensor  662  that monitors operating conditions of the contact members  557 ,  558  and outputs a signal to an input/output element  664  powered by an onboard power supply such as a battery  670 . When predetermined operating conditions are detected with the sensor  662 , the input/output element  664  outputs a signal to a output signal port  672  or alternatively to a communications device  674  that wirelessly communicates with a remotely located overview and response dispatch system  676  that alerts, notifies, and summons maintenance personnel or responsible technicians to respond to tripping and opened fuse conditions to restore or re-energize associated circuitry with minimal downtime. 
     Optionally, an input signal port  678  may be included in the monitoring module  652 . The input signal port  678  may be interconnected with an output signal port  672  of another monitoring module, such that signals from multiple monitoring modules may be daisy chained together to a single communications device  674  for transmission to the remote system  676 . Interface plugs (not shown) may be used to interconnect one monitoring module to another in an electrical system. 
     In one embodiment, the sensor  662  is a voltage sensing latch circuit having first and second portions optically isolated from one another. When the primary fuse element  680  of the fuse  442  opens to interrupt the current path through the fuse, the sensor  662  detects the voltage drop across the terminal elements T 1  and T 2  (the solenoid contact members  557  and  558 ) associated with the fuse  442 . The voltage drop causes one of the circuit portions, for example, to latch high and provide an input signal to the input/output element  664 . Acceptable sensing technology for the sensor  662  is available from, for example, SymCom, Inc. of Rapid City, S.D. 
     While in the exemplary embodiment, the sensor  662  is a voltage sensor, it is understood that other types of sensing could be used in alternative embodiments to monitor and sense an operating state of the fuse  442 , including but not limited to current sensors and temperature sensors that could be used to determine whether the primary fuse element  680  has been interrupted in an overcurrent condition to isolate or disconnect a portion of the associated electrical system. 
     In a further embodiment, one or more additional sensors or transducers  682  may be provided, internal or external to the monitoring module  652 , to collect data of interest with respect to the electrical system and the load connected to the fuse  442 . For example, sensors or transducers  682  may be adapted to monitor and sense vibration and displacement conditions, mechanical stress and strain conditions, acoustical emissions and noise conditions, thermal imagery and thermalography states, electrical resistance, pressure conditions, and humidity conditions in the vicinity of the fuse  442  and connected loads. The sensors or transducers  682  may be coupled to the input/output device  664  as signal inputs. Video imaging and surveillance devices (not shown) may also be provided to supply video data and inputs to the input/output element  664 . 
     In an exemplary embodiment, the input/output element  664  may be a microcontroller having a microprocessor or equivalent electronic package that receives the input signal from the sensor  662  when the fuse  442  has operated to interrupt the current path through the fuse  442 . The input/output element  664 , in response to the input signal from the sensor  662 , generates a data packet in a predetermined message protocol and outputs the data packet to the signal port  672  or the communications device  674 . The data packet may be formatted in any desirable protocol, but in an exemplary embodiment includes at least a fuse identification code, a fault code, and a location or address code in the data packet so that the operated fuse may be readily identified and its status confirmed, together with its location in the electrical system by the remote system  676 . Of course, the data packet could contain other information and codes of interest, including but not limited to system test codes, data collection codes, security codes and the like that is desirable or advantageous in the communications protocol. 
     Additionally, signal inputs from the sensor or transducer  682  may be input the input/output element  664 , and the input/output element  664  may generate a data packet in a predetermined message protocol and output the data packet to the signal port  672  or the communications device  674 . The data packet may include, for example, codes relating to vibration and displacement conditions, mechanical stress and strain conditions, acoustical emissions and noise conditions, thermal imagery and thermalography states, electrical resistance, pressure conditions, and humidity conditions in the vicinity of the fuse  442  and connected loads. Video and imaging data, supplied by the imaging and surveillance devices  682  may also be provided in the data packet. Such data may be utilized for troubleshooting, diagnostic, and event history logging for detailed analysis to optimize the larger electrical system. 
     The transmitted data packet from the communications device  674 , in addition to the data packet codes described above, also includes a unique transmitter identifier code so that the overview and response dispatch system  676  may identify the particular monitoring module  652  that is sending a data packet in a larger electrical system having a large number of monitoring modules  652  associated with a number of fuses. As such, the precise location of the affected disconnect module  500  in an electrical system may be identified by the overview and response dispatch system  676  and communicated to responding personnel, together with other information and instruction to quickly reset affected circuitry when one or more of the modules  500  operates to disconnect a portion of the electrical system. 
     In one embodiment, the communications device  674  is a low power radio frequency (RF) signal transmitter that digitally transmits the data packet in a wireless manner. Point-to-point wiring in the electrical system for fuse monitoring purposes is therefore avoided, although it is understood that point-to-point wiring could be utilized in some embodiments of the invention. Additionally, while a low power digital radio frequency transmitter has been specifically described, it is understood that other known communication schemes and equivalents could alternatively be used if desired. 
     Status indicators and the like such as light emitting diodes (LED&#39;s) may be provided in the monitoring module  652  to locally indicate an operated fuse  442  or a tripped disconnect condition. Thus, when maintenance personnel arrives at the location of the disconnect module  500  containing the fuse  442 , the status indicators may provide local state identification of the fuses associated with the module  500 . 
     Further details of such monitoring technology, communication with the remote system  676 , and response and operation of the system  676  are disclosed in commonly owned U.S. patent application Ser. No. 11/223,385 filed Sep. 9, 2005 and entitled Circuit Protector Monitoring Assembly, Kit and Method. 
     While the monitoring features have been described in the context of an add-on module  652 , it is understood that the components of the module  652  could be integrated into the module  500  if desired. Single pole or multiple pole versions of such a device could likewise be provided. Additionally, the monitoring module  652  and the auxiliary contact module could each be used with a single disconnect module  500  if desired, or alternative could be combined in an integrated device with single pole or multiple pole capability. 
       FIG. 28  is a side elevational view of a portion of a twelfth embodiment of a fusible switching disconnect module  700  that is constructed similarly to the disconnect module  500  described above but includes a bimetallic overload element  702  in lieu of the solenoid described previously. The overload element  702  is fabricated from strips of two different types of metallic or conductive materials having different coefficients of thermal expansion joined to one another, and a resistance alloy joined to the metallic elements. The resistance alloy may be electrically isolated from the metallic strips with insulative material, such as a double cotton coating in an exemplary embodiment. 
     In use, the resistance alloy strip is joined to the contact members  557  and  558  and defines a high resistance parallel connection across the ferrules  462  and  466  of the fuse  442 . The resistance alloy is heated by current flowing through the resistance alloy and the resistance alloy, in turn heats the bimetal strip. When a predetermined current condition is approached, the differing rates of coefficients of thermal expansion in the bimetal strip causes the overload element  702  to bend and displace the trip bar  545  to the point of release where the spring loaded actuator  504  and sliding bar  456  move to the opened positions to disconnect the circuit through the fuse  442 . 
     The module  700  may be used in combination with other modules  500  or  700 , auxiliary contact modules  602 , and monitoring modules  652 . Single pole and multiple pole versions of the module  700  may also be provided. 
       FIG. 29  is a side elevational view of a portion of a thirteenth embodiment of a fusible switching disconnect module  720  that is constructed similarly to the disconnect module  500  described above but includes an electronic overload element  722  that monitors current flow through the fuse by virtue of the contact members  557  and  558 . When the current reaches a predetermined level, the electronic overload element  722  energizes a circuit to power the solenoid and trip the module  720  as described above. The electronic overload element  722  may likewise be used to reset the module after a tripping event. 
     The module  702  may be used in combination with other modules  500  or  700 , auxiliary contact modules  602 , and monitoring modules  652 . Single pole and multiple pole versions of the module  700  may also be provided. 
       FIG. 30  is a perspective view of a fuse status indicator module  800  that may be used in combination, for example, with any of the disconnect devices and modules described above. That is, the fuse status indicator module  800  may be used with the fusible disconnect devices  100  ( FIG. 1 ),  300  ( FIGS. 8 and 9 ),  370  ( FIG. 10 ),  400  ( FIG. 11 ), and  600  ( FIGS. 23 and 24 ). The fuse status indicator module  800  may also be used in combination with one or more of the disconnect modules  102  ( FIGS. 2-4 ),  220  ( FIG. 5 ),  250  ( FIGS. 6 and 7 ),  410  ( FIGS. 12-16 ),  500  ( FIG. 17-22 ),  650  ( FIGS. 25 and 26 ),  700  ( FIG. 28 ), and  720  ( FIG. 29 ). As such, the fuse status indicator module  800  may be utilized with single or multi-pole disconnect mechanisms, may have various mounting and connection options to protected circuitry, may be used with different types and configurations of fuses, may be used in combination with undervoltage modules, tripping mechanisms, auxiliary contact modules and elements, overload elements, and even other types of monitoring elements. The fuse status indicating module  800  may be considered a lower cost option than the monitoring module  652  ( FIGS. 25 and 26 ) for providing remote detection of operating states of the fuses in the disconnect devices and modules. 
     The monitoring module  800  may include a housing  802  generally complementary in shape to the housings described above for the various disconnect devices and modules, and in an exemplary embodiment the housing  802  has a thickness dimension T of about one half the thickness dimensions of the modules described above, or about 8.75 mm in one example. Like some of the housings described above, the housing  802  includes mounting openings or apertures  803  that may receive connectors or shims, such as the connectors pins  480  and shims  484  ( FIG. 16 ) to gang the housing  802  to a disconnect device or module having complementary mounting openings and apertures. 
     The housing  802  contains sensing and indication components and circuitry described below to detect opening of fuses in the associated disconnect device and disconnect modules. The module  800  also includes an actuator  804  that may be tied to the actuator of a disconnect device with a connector pin  806  in the manner described above. Signal input ports  808  are provided on either side of the housing  802 , and wire leads or conductors  810   a ,  810   b , and  810   c  internally connect to the sensing components and circuitry in the housing  802  and extend through the signal ports  808  for external connection to terminal elements of a disconnect device or disconnect modules the define the line and load connections to the fuses. 
     In the illustrated embodiment, each wire lead  810   a ,  810   b  and  810   c  terminates outside the signal ports  808  with fork terminal connectors  812   a ,  812   b  and  812   c . The terminal connectors  812   a ,  812   b  and  812   c  may be extended into corresponding ports in the disconnect device and any associated disconnect modules, therefore establishing line and load connections to the terminal elements therein. When so connected, the wire leads  810   a  and terminal connectors  810   b  provide electrical connection to a first fuse to be monitored with the module  800 , the wire leads  810   b  and terminal connectors  812   b  provide electrical connection to a second fuse to be monitored with the module  800 , and the wire leads  810   c  and terminal connectors  812   c  provide electrical connection to a third fuse to be monitored by the module  800 . While forked terminal connectors  812   a ,  812   b  and  812   c  are illustrated in  FIG. 30 , it is recognized that other terminal structure could be provided to connect the wires leads  810   a ,  810   b  and  810   c  to the line and load terminal structure of the disconnect device and modules. 
     The three pairs of wire leads  810   a ,  810   b  and  810   c  are particularly beneficial for a three phase disconnect device supplying AC electrical power to a motor or industrial machine, for example. While three wires  810   a ,  810   b  and  810   c  are illustrated, it is understood that in an alternative embodiment greater or fewer lead wires  810  may be provided to monitor greater or fewer numbers of fuses. Additionally, to the extent the module  800  is desired for use with a disconnect device having less than three poles, the unused terminal connectors  812  of the module  800  may be capped or otherwise covered. 
     Light emitting diodes (LEDs)  814  and  816  may be provided and connected to circuitry in the housing  802  and may be visible from an exterior of the housing  802 . In an exemplary embodiment, the LED  814  may provide an indication of electrical power supplied to the module  800 , and the LED  816  may provide indication of an opened fuse in the associate disconnect device or module. For example, in one embodiment, the LED  814  may be illuminated to indicate that power to the module  802  is being received, sometimes referred to as an “on” condition, and is not illuminated when power to the module  802  is absent, sometimes referred to as an off condition. In another embodiment, this indication of on or off conditions may be effectively reversed such that the LED  814  is lit when power is lost and the LED  814  is not lit when the power is on. In any event, by virtue of the power LED  814 , a user may quickly ascertain whether the module  800  is receiving electrical power. 
     Likewise, the fuse indication LED  816 , may not be illuminated when the fuses are in an unopened or operative, current carrying state for normal operation, and the LED  816  may be illuminated when at least one of the monitored fuses opens to interrupt or break the current path and the electrical connection through the fuse. In an alternative embodiment, this indication may be reversed such that the LED  816  is lit when the fuses are unopened and is not lit when the fuses are opened. In any event, by virtue of the LED  816 , the user may quickly ascertain whether or not any of the fuses have opened and need replacement. Local fuse state indication in the vicinity of the module  800  is therefore provided by the LED  816 . 
     For remote fuse state indication, output ports and terminal connectors  818 ,  820  and  822  are provided in the module  800 . The connectors  818 ,  820  and  822  provide for connection to a controller, such as a programmable logic controller, that is in turn connected to remote devices and equipment. The connector  818 , for example, may correspond to a ground connection. The connector  820  may correspond to a power connection to the module  800 , such as a 24V DC connection to a power supply of the controller. The connector  822  may correspond to a signal connection, such as 0V or 24V DC signal to the controller. In one embodiment, the connectors  818 ,  820  and  822  are known 16 AWG 0.110 quick connect terminal connectors, although it is contemplated that other connectors and terminals could be utilized in an alternative embodiment if desired. 
       FIG. 31  is a side elevational view of a portion of the module  802  illustrating its internal components. The housing  802  surrounds and protects a circuit board assembly  830 , and the lead wires  810  are passed through the signal ports  808 . Strain relief features  832  are molded into the housing  802 , for example, to protect the lead wires  810  and their connections to the circuit board assembly  830 . Optical isolators  834  are provided to interface the wire leads  810  and 600V AC circuitry of the fuses from the 24V DC circuitry of the circuit board assembly  830 . Each optical isolator  834   a ,  834   b  and  834   c  corresponds to one of the monitored fuses operatively connected between each of the lead wires  810   a ,  810   b  and  810   c , respectively. The optical isolators  834  latch when a voltage differential appears across one of the fuses as explained further below. 
     The printed circuit board assembly  130  may also include the LEDs  814  and  816  and terminals  836 ,  838  and  840  for the connectors  818 ,  820  and  822  in  FIG. 31 . The terminals  836 ,  838  and  840  may be, for example, 0.100 spade terminals known in the art. 
     A bypass/reset switch  842  is also provided in the circuit board assembly  830 . The switch  842  is actuated by a cam surface  844  of the actuator  804 . The switch  842  and cam surface  844  are constructed so that when the actuator  804  is tied to actuator of the disconnect device or module, movement of the actuator  804  in the direction of arrow J causes the cam surface  844  to operate the switch  842  as the switch contacts in the disconnect device or module are opened. Operation of the switch  842  bypasses signal portions of the circuitry in the module  800  and also causes the fuse indicating LED  816  to be reset. Bypassing of the signal portions of the circuitry prevents an open fuse signal from occurring when the disconnect device or module is opened. That is, operation of the circuitry is unaffected by the position of the switch contacts in the disconnect device or whether the disconnect device is opened or closed to connect or disconnect the current path through the fuses. 
       FIG. 32  is an exemplary fuse status indicating circuit schematic for the module  800 . The circuit includes a sensing or detecting portion  850  and a signal portion  852  each connected to a power supply  854 . The sensing portion  850  includes the optical isolators  834   a ,  834   b ,  834   c  connected across each respective Fuse  1 , Fuse  2 , and Fuse  3  of the disconnect device, and the fuse indicating LED  816 . In a normal operating condition, for example, and when none of the fuses Fuse  1 , Fuse  2  or Fuse  3  has opened, the optical isolators  834   a ,  834   b ,  834   c  experience no voltage differential and the sensing portion  850  of the circuit is unlatched and the LED  816  is not illuminated. Additionally, in the normal operation condition and when none of the fuses Fuse  1 , Fuse  2  or Fuse  3  has opened, the signal portion  852  of the circuit is set high and provides accordingly provides a high signal input to the controller via the terminal  822  ( FIG. 30 ) and the terminal  840  ( FIG. 31 ). By virtue of the switch  842 , the signal portion  852  is unaffected by opening of the switch contacts in the disconnect device. That is, in an exemplary embodiment the signal portion  852  remains high whether the disconnect device is open or closed. Only when a primary fuse element in one of the fuses actually opens is the signal set low in the signal portion  852 . 
     Open fuse events are detected by the optical isolators  834   a ,  834   b ,  834   c  in the sensing portion  850  of the circuit, which in turn causes the signal portion  852  to provide a low signal to the controller. More specifically, the optical isolators  834   a ,  834   b ,  834   c  sense a voltage drop across the line and load terminals of the fuse via the line and load terminals of the disconnect device or modules. Each of the fuses Fuse  1 , Fuse  2 , and Fuse  3  may correspond to a respective phase of AC electrical power feeding, for example, a motor or industrial machine. When any of the fuses Fuse  1 , Fuse  2 , and Fuse  3  opens, the voltage placed across the associated optical isolator  834   a ,  834   b  or  834   c  causes the sensing portion  850  of the circuit to latch and illuminate the fuse indicating LED  816  to indicate an open fuse event. 
     The latching of the circuit and lighting of the LED  816 , in turn, causes the signal portion  852  to set low and input the low signal to the controller. When the controller receives the low signal at a remote location, an opened fuse event is detected. The controller may be programmed, for example, to open a contactor or other device to prevent the motor or machine, for example, from running on less than three phases of current. Additionally, the controller may be programmed to set an alarm condition for prompt action by an operator, provide notification to certain persons of an opened fuse, or execute other instructions provided in the controller programming as desired. 
     Once the signal portion  852  is set low it remains low until the reset switch  842  is activated using the module actuator  804  to reset the signal portion  852  to high. The low signal may be maintained even if the voltage is removed across the opened fuse, such as by opening one of the switch contacts in the associated disconnect device. By maintaining the low signal in such a manner, the opened fuse indication will continue even after the associated disconnect device is opened. 
     Activation of the switch  842  with the actuator  804  also resets the signal portion  850  and the LED  816  after an open fuse detection event. 
     While in the illustrative embodiment open fuse events are detected with optical isolators, it is understood that other detecting elements and components could be utilized with similar effect, and such detecting elements may monitor and respond to sensed or detected current, voltage, temperature and other operating conditions to detect open fuses. Numerous sensing and detecting elements are known that would be suitable for the indication module as described, including but not limited to current transformers, Rogowski coils, inductors, and the like as those in the art will appreciate. 
     Likewise, while visual indicators in the form of LEDs are provided in an exemplary embodiment so that open fuses may be efficiently located, it is contemplated that other types of visual indicators may alternatively be provided to identify open fuse events with a change in external appearance of the indication module. A variety of visual indicators are known in the art and may alternatively be utilized, including, for example, mechanical indicators having flags or pins that are extended in response to open fuses, electrical indicators having one or more light emitting elements, and indicators exhibiting color changes in response to open fuse events, including but not limited to combustible indicators and indicators having temperature responsive materials and chemically activated color changes. 
       FIG. 33  illustrates the fuse status indicating module  800  connected or ganged to a fusible disconnect device  860 . The disconnect device  860  may include a number of disconnect modules  862  or may be provided in a single housing as desired. The modules  862  may be of the type described above including a fuse compartment and fuse terminals, a sliding bar and switch contacts. The modules  862  may further include the addition of access ports  864  for insertion of the terminals  812   a ,  812   b  and  812   c  ( FIG. 3 ) connected to each wire lead  810   a ,  810   b , and  810   c . The terminals  812   a ,  812   b  and  812   c  electrically connect to the fuse terminals to place the optical isolators  834   a ,  834   b  and  834   c  across the fuses in each module  862 . 
     Fuse covers  865  are provided on each of the modules  862  of the disconnect device  860 , and the covers  865  are positionable to provide access to the fuse compartments for insertion and removal of the fuses. The disconnect device  860  includes an actuator  866  for opening of the switch contacts via the sliding bar as described above, and the actuator  804  of the indicating module  800  is linked to the actuator  866  of the disconnect device  860 . The connectors  818 ,  820  and  822  are accessible on the module  800  for connection to the controller for power, ground and signal connections via connecting plugs and wires or cables. 
       FIG. 34  schematically illustrates a fused electrical system  900  including the fusible disconnect device  860 , fuse state indication module  800 , a power supply  902  and a controller  904 . The electrical system includes line and load connections and circuitry coupled to the fuses Fuse  1 , Fuse  2  and Fuse  3  in the disconnect device  860 . A power supply  902  such as a battery is coupled to the indication module  800  via the power connector  820  and cabling  906 . Ground connections are established to the module  800  via the connector  818  and cabling  908 . A signal connection between the indicating module  800  and the controller  904  is established via the signal connector  822  and cabling  910 . Once so connected, the indicating module  800  may signal the controller  904  of open fuse events as they occur, and controller  904  may generate alarms, take appropriation and measures, etc. according to the programming of the controller. 
     Having now described the system and its operation functionally, it is believed that programming of the controller is within the purview of those in the art without further explanation. 
     Embodiments of fusible disconnect devices are therefore described herein that may be conveniently switched on and off in a convenient and safe manner without interfering with workspace around the device. The disconnect devices may be reliably switch a circuit on and off in a cost effective manner and may be used with standardized equipment in, for example, industrial control applications. Further, the disconnect modules and devices may be provided with various mounting and connection options for versatility in the field, together with remote monitoring and control capability. 
     One embodiment of a fuse status indicator module for a disconnect device having at least one fuse therein is disclosed herein. The monitoring module comprises a housing; a switch within the housing; a switch actuator extending from the housing and operatively coupled to the switch; at least one open fuse detecting element contained within the housing; and at least one pair of wire leads connected to the optical isolator and attachable to the disconnect device to establish an electrical connection with the fuse, wherein the open fuse detecting element detects opening of the fuse. 
     Optionally, the open fuse detecting element may comprise an optical isolator. A control interface connector may also be provided, with the connector comprising at least one of a power connector, a ground connector and a signal connector. A plurality of open fuse detecting elements may be provided, with each open fuse detecting element corresponding to a fuse in the disconnect device. Terminals connected to the lead wires may be provided, and the terminals may comprise forked terminals. The actuator may comprise a cam surface, with the cam surface operating the switch. The pair of wire leads may comprise a first pair, a second pair and a third pair. At least one visual indicator may be coupled to the housing, and the indicator may be configured to change in appearance when an open fuse is detected. The visual indicator may comprise an LED visible from an exterior of the housing. The housing may be configured for ganged connection with the disconnect device. 
     An embodiment of a fusible switch disconnect device is disclosed. The device comprises a disconnect housing adapted to receive at least one fuse therein, with the fuse being separately provided from the housing and being removably insertable in the housing. Line side and load side terminals are connected to the fuse when the fuse is inserted into the housing, with at least one of the line and load-side terminals comprising a first stationary switch contact provided between the respective line side terminal and load side terminal and the fuse. A fuse terminal is adapted to engage a conductive element of the fuse when inserted into the disconnect housing, and the fuse terminal is coupled to a second stationary switch contact. A sliding bar is provided within the disconnect housing, and the sliding bar is provided with first and second movable contacts corresponding to the first and second stationary switch contacts. A rotatably mounted switch actuator is adapted to position the sliding bar and first and second movable contacts between an open position and a closed position relative to the first and second stationary switch contacts to connect or disconnect an electrical connection through the fuse, and a fuse status indicator module is provided. The fuse status indicator module comprises a housing configured to couple to the disconnect housing, an open fuse detecting element within the housing, and wire leads coupling the optical isolator to the line side and load side terminals of the disconnect housing. 
     Optionally, the open fuse detecting element comprises at least one optical isolator. The disconnect housing may includes access ports to the line side and load side terminals. The indicator module may further comprise a control interface connector, with the connector comprising at least one of a power connector, a ground connector and a signal connector. The open fuse detecting element may comprise a plurality of open fuse detecting elements each corresponding to a fuse in the disconnect device. The indicator module may further comprise terminals connected to the lead wires, and the terminals may comprise forked terminals. The indicator module may further comprise an actuator and a switch, the actuator comprising a cam surface, the cam surface operating the switch. The at least one pair of wire leads may comprises a first pair, a second pair and a third pair. At least one visual indicator may be provided on the fuse status indicator module, and the visual indicator may comprise an indicating LED visible from an exterior of the housing of the fuse status indicator module. 
     Another embodiment of a fusible switch disconnect device is disclosed herein. The device comprises a disconnect housing adapted to receive at least one fuse therein, with the disconnect housing including a line side terminal and a load side terminal to complete an electrical connection through the fuse. The fuse is separately provided from the housing and is removably insertable in the housing. The disconnect housing further comprises switch contacts for connecting and disconnecting the electrical connection through the fuse. A fuse status indicator is also provided, and the indicator comprises: wire leads connected the line side terminal and the load side terminal; an open fuse detecting element connected to the wire leads; and local and remote fuse state indication means, the local and remote fuse state indication means being operationally unaffected by a position of the switch contacts connecting and disconnecting the electrical connection through the fuse. 
     Optionally, the local fuse state indication means comprises a visual indicator. The remote fuse state indication means may comprise a control interface connector. The detecting element may comprise an optical isolator. The indicator module may further comprise a switch and a switch actuator. The switch actuator may comprise a cam surface. The fuse status indicator may be separately fabricated from the disconnect housing and may be adapted for ganged connection with the disconnect housing. 
     An embodiment of a fusible switch disconnect device is also disclosed that comprises: means for receiving and containing at least one fuse, the fuse being separately provided from the means for receiving; means for mechanically and electrically connecting to the fuse when the fuse is inserted into the means for receiving; means for switching a conductive path to the means for electrically connecting and disconnecting the fuse when desired, the means for switching being located within the means for receiving; and means for indicating an opening of the fuse, the means for indicating being separately provided from the means for receiving and also separately provided from the fuse, wherein the means for indicating is removably coupled to the means for receiving. 
     Optionally, the means for indicating further comprises means for detecting an opening of the fuse, and means for bypassing the means for detecting. 
     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.