ELECTRICAL INSTALLATIONS INCLUDING SAME

Field of the Invention

[0001] The present invention relates to surge protective devices.

Background

[0002] Frequently, excessive voltage or current is applied across service lines that deliver power to residences and commercial and institutional facilities. Such excess voltage or current spikes (transient overvoltages and surge currents) may result from lightning strikes, for example. The above events may be of particular concern in telecommunications distribution centers, hospitals and other facilities where equipment damage caused by overvoltages and/or current surges is not acceptable and resulting down time may be very costly.

[0003] Typically, sensitive electronic equipment may be protected against transient overvoltages and surge currents using surge protective devices (SPDs). For example, an overvoltage protection device may be installed at a power input of equipment to be protected, which is typically protected against overcurrents when it fails. Typical failure mode of an SPD is a short circuit. The overcurrent protection typically employed is a combination of an internal thermal disconnector to protect the device from overheating due to increased leakage currents and an external fuse to protect the device from higher fault currents. Different SPD technologies may avoid the use of the internal thermal disconnector because, in the event of failure, they change their operation mode to a low ohmic resistance.

[0004] In the event of a surge current in a line L (e.g. , a voltage line of a three-phase electrical power circuit), protection of power system load devices may necessitate providing a current path to ground for the excess current of the surge current. The surge current may generate a transient overvoltage between the line L and the neutral line N (the neutral line N may be conductively coupled to an earth ground PE). Since the transient overvoltage significantly exceeds the operating voltage of the SPD, the SPD will become conductive, allowing the excess current to flow from line L through the SPD to the neutral N. Once the surge current has been conducted to neutral N, the overvoltage condition ends and the SPD may become non-conducting again. However, in some cases, one or more SPDs may begin to allow a leakage current to be conducted even at voltages that are lower that the operating voltage of the SPDs. Such conditions may occur in the case of an SPD deteriorating. Summary

[0005] According to some embodiments, a surge protective electrical installation includes an enclosure, a set of elongate busbars, and a surge protective device (SPD) assembly. The enclosure includes a front cover. The front cover includes an access opening defined therein. The set of elongate busbars is disposed in the enclosure behind the front cover and has a busbar longitudinal axis. The SPD assembly includes a base module and an SPDS module. The base module is mounted on the busbars to mechanically and electrically connects the base module to the busbars. The base module includes a first lateral section and a second lateral section. The SPD module is removably mounted on the second lateral section of the base module. The SPD module includes an overvoltage clamping element. The front cover is selectively positionable in each of an open position and a closed position. When the front cover is in the closed position, the first lateral section of the base module is covered by the front cover, and the SPD module is not covered by the front cover so that the SPD module is exposed through or projects through the access opening. When the front cover is in the open position, the first lateral section of the base module is not covered by the front cover.

[0006] According to some embodiments, a surge protective device (SPD) assembly for use with an enclosure and a set of busbars, the enclosure including a front cover having an access opening defined therein, the set of elongate busbars being disposed in the enclosure behind the front cover and having a busbar longitudinal axis, includes a base module and an SPDS module. The base module is configured to be mounted on the busbars to mechanically and electrically connect the base module to the busbars. The base module includes a first lateral section and a second lateral section. The SPD module is removably mounted on the second lateral section of the base module. The SPD module includes an overvoltage clamping element. The SPD assembly is configured to be mounted on the busbars in the enclosure such that: when the front cover is in a closed position, the first lateral section of the base module is covered by the front cover, and the SPD module is not covered by the front cover so that the SPD module is exposed through or projects through the access opening; and when the front cover is in the open position, the first lateral section of the base module is not covered by the front cover.

[0007] According to some embodiments, a surge protective device (SPD) assembly for mounting on a set of busbars includes a base module, an overvoltage clamping element, and a dual terminal cable clamping connector. The base module is configured to be mounted on the busbars to mechanically and electrically connect the base module to the busbars. The dual terminal cable clamping connector includes a cage member, a connector body, and a threaded member. The cage member defines a cage cavity. The connector body includes a cable engagement portion. The cable engagement portion extends into the cage member and partitions the cage cavity into a first cable socket and a second cable socket. The threaded member is operable to displace the cage member relative to the cable engagement portion. The first cable socket is configured to receive a first cable. The second cable socket is configured to receive a second cable. The threaded member is operable to: clamp the first cable in the first cable socket between the cable engagement portion and the cage member; and clamp the second cable in the second cable socket between the cable engagement portion and the threaded member.

[0008] According to some embodiments, a surge protective device (SPD) assembly for mounting on a set of busbars includes a base module and an overvoltage clamping element. The base module is configured to be mounted on a front side of the busbars to mechanically and electrically connect the base module to the busbars. The base module includes integral busbar mounting features and an integral guard wall. The integral busbar mounting features each define a busbar slot to receive a respective busbar when the base module is mounted on the busbars. Each busbar mounting feature has a rearmost end. The integral guard wall projects rearwardly beyond the rearmost ends of the busbar mounting features. In some embodiments, each busbar mounting feature is an integral hook.

Brief Description of the Drawings

[0009] FIG. 1 is a front perspective view of an SPD assembly according to some embodiments.

[00010] FIG. 2 is a rear perspective view of the SPD assembly of FIG. 1.

[00011] FIG. 3 is a front view of an electrical power supply system including an installation according to some embodiments, the installation including an enclosure, a set of busbars, and the SPD assembly of FIG. 1.

[00012] FIG. 4 is a cross-sectional view of the installation of FIG. 3 taken along the line 4-4 of FIG. 3.

[00013] FIG. 5 is a cross-sectional view of the installation of FIG. 3 taken along the line 5-5 of FIG. 3.

[00014] FIG. 6 is a front view of the SPD assembly of FIG. 1. [00015] FIG. 7 is a cross-sectional view of the SPD assembly of FIG. 1 taken along the line 7-7 of FIG. 6.

[00016] FIG. 8 is a front view of a base electrical circuit forming a part of the SPD assembly of FIG. 1.

[00017] FIG. 9 is an exploded, front perspective view of the base electrical circuit of FIG. 8

[00018] FIG. 10 is a perspective view of a clamp connector forming a part of the SPD assembly of FIG. 1.

[00019] FIG. 11 is a cross-sectional view of the clamp connector of FIG. 10.

[00020] FIG. 12 is an exploded, front perspective view of an SPD module forming a part of the SPD assembly of FIG. 1.

[00021] FIG. 13 is a cross-sectional view of the SPD module of FIG. 12.

[00022] FIG. 14 is a schematic electrical circuit diagram of the SPD assembly of FIG. 1

[00023] FIG. 15 is a schematic electrical circuit diagram of an SPD assembly according to further embodiments.

Description

[00024] The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. In the drawings, the relative sizes of regions or features may be exaggerated for clarity. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[00025] It will be understood that when an element is referred to as being "coupled" or "connected" to another element, it can be directly coupled or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly coupled" or "directly connected" to another element, there are no intervening elements present. Like numbers refer to like elements throughout.

[00026] In addition, spatially relative terms, such as "under", "below", "lower", "over", "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "under" or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the exemplary term "under" can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[00027] Well-known functions or constructions may not be described in detail for brevity and/or clarity.

[00028] As used herein the expression "and/or" includes any and all combinations of one or more of the associated listed items.

[00029] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[00030] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[00031] As used herein, "monolithic" means an object that is a single, unitary piece formed or composed of a material without joints or seams. Alternatively, a unitary object can be a composition composed of multiple parts or components secured together at joints or seams.

[00032] With reference to FIGS. 1-14, a surge protective device (SPD) assembly 100 according to embodiments of the present invention is shown therein. The SPD assembly 100 is modular and includes three SPD modules 200 and a pedestal or base module 102. Each of the SPD modules 200 is selectively pluggable into and removable from the base module 102. For example, each of the SPD modules 200 can be individually removed and replaced in the event the SPD module 200 fails or if an SPD module having a different rating or different performance characteristics is desired.

[00033] With reference to FIGS. 3-5, the SPD assembly 100 may be used in an electrical power supply system 10 to form a surge protective electrical installation 11 according to embodiments of the invention. The illustrated surge protective electrical installation 11 includes an enclosure 40 containing a set 60 of three electrically conductive busbars LI, L2, L3, one or more neutral line cables CN and one or more ground or protected earth cables CG. The busbars LI, L2 and L3 are each connected to a respective one of three voltage lines of a three-phase electrical power supply system. The neutral line cable CN is connected to a neutral line of the three-phase electrical power supply system. The ground cable CG is connected to a ground or protected earth ground. Each of the three phase lines may be provided with a main circuit breaker or fuse in or near the enclosure 40, for example. The SPD assembly 100 is mounted on the busbars LI, L2, L3 to protect equipment connected to the busbars LI, L2, L3 from transient overvoltages and surge currents.

[00034] The busbars LI, L2 and L3 may be formed of metal. In some embodiments, the busbars LI, L2 and L3 are flat busbars. In some embodiments, the busbars LI, L2 and L3 are configured as a 60 mm busbar system (/.< ., busbars having on-center spacing between adjacent busbars of 60 mm). In some embodiments, the busbars LI, L2 and L3 are compliant with DIN 61439-1 :2011.

[00035] The busbars LI, L2 and L3 are elongate. The busbars LI, L2, L3 extend substantially parallel to one another. The busbar set 60 has a longitudinal axis B-B extending along or parallel to the length of each busbar LI, L2, L3, a serial axis C-C perpendicular to the axis B-B, and a depthwise axis D-D perpendicular to each of the axes B-B and C-C. Relative positions along the longitudinal axis B-B may be referred to as left and right; relative positions along the serial axis C-C may be referred to as upper and lower; and relative positions along the depthwise axis D-D may be referred to as front and rear. However, it will be appreciated that the busbars may be otherwise oriented. For example, the busbars may extend vertically instead of horizontally, in which case the serial axis C-C would extend left-right and the longitudinal axis B-B would extend upper-lower.

[00036] The enclosure 40 may include a rack, cabinet, closet or other suitable structure for supporting and containing the set of busbars 60. In some embodiments, the enclosure 40 is a cabinet. In some embodiments, the enclosure 40 is a rack. In some embodiments, the enclosure 40 is a closet. [00037] The enclosure 40 defines a chamber 42 and an enclosure opening 43, and includes a front cover 44. The front cover 44 includes a panel 45 and a cutout or access opening 46 (defined by an inner edge or perimeter 46 A of the panel 45). The front cover 44 is movable relative to the chamber 42 between a closed or installed position (as shown in FIGS. 3-5) and an open or removed position. When the front cover 44 is in the closed position, the access opening 46 overlies (along the depthwise axis D-D) an exposed or open region 42A of the chamber 42, and the panel 45 overlies (along the depthwise axis D-D) a covered or closed region 42B of the chamber 42. In the open or removed position of the front cover 44, the panel 45 is pulled away, and the full enclosure opening 43 is exposed and accessible from the front of the enclosure 40. The enclosure opening 43 is larger than the access opening 46.

[00038] The base module 102 includes a base housing 110, a busbar mounting system 119 (including a locking mechanism 170), a base electrical circuit 140, a remote signaling system 158, a dual terminal protected earth (PE) or ground terminal 160G, and dual terminal neutral terminal 160N. Each of these components and systems forms an integral part of the base module 102 and is disposed on the base housing 110, as discussed in more detail below. As is apparent from the drawings, in some embodiments, the base electrical system 140 and the terminals 160G, 160N are enclosed in the housing 110.

[00039] The base module 102 has a primary or longitudinal axis F-F, a lateral axis G- G perpendicular to the axis F-F, and a heightwise axis H-H perpendicular to each of the axes F-F and G-G

[00040] When the base module 102 is mounted on the busbars LI, L2, L3 as shown in the figures and discussed herein, the primary axis F-F extends parallel to the serial axis C- C, the lateral axis G-G extends substantially parallel to the longitudinal axis B-B, and the heightwise axis H-H extends substantially parallel to the depthwise axis D-D.

[00041] As used herein, “front” or “distal” refers to the end of the base module 102 farther away from the busbars LI, L2, L3 when the module 100 is mounted on the busbars LI, L2, L3, and “rear” or “proximal” refers to the end of the base module 102 nearer the busbars LI, L2, L3.

[00042] The base module 102 has a front side 104F, an opposing rear side 104R, a first or upper end 104U, and an opposing second or lower end 104L. As discussed below, the footprint of the base module 102 (viewed from the front side 104F, as shown in FIG. 6) includes a left lateral section 106J, a right lateral section 106K, an upper right section 106U, and a lower right section 106L. [00043] The base housing 110 includes a main section 112. One or more cavities defined in the base housing 110 contain components of the electrical circuit 140.

[00044] Four spaced apart, integral towers 114 project forwardly from the main section 112. Three module receiving sockets, slots or seats 122 are defined in the base housing 110 between the towers 114. A pair of module contact ports 124 is provided in each module seat 122. The seats 122 are sized to receive the SPD modules 200. The base module 102 may include locking mechanisms 202 to lock the SPD modules 200 in place. The locking mechanisms 202 may be constructed and operated as described in European Patent No. 3 236 548 (Attorney Docket No. 9360.28. EP), the disclosure of which is incorporated herein by reference.

[00045] Three integral, L-shaped busbar mounting features or legs 116 project rearwardly from the rear side of the main section 112. In some embodiments and as illustrated in FIGS. 1 and 4, each mounting feature 116 is an L-shaped hook. A respective busbar receiving or mounting slot 126 is defined within each mounting leg 116. Each mounting leg 116 extends rearwardly (z.e., along the axis H-H) from the main section 112 to a mounting leg rearmost end 116A.

[00046] A first integral guard feature, projection, wall or tab 120A projects rearwardly from the main section 112 on the upper end 104U. A second integral guard feature, projection, wall or tab 120B projects rearwardly from the main section 112 on the lower end 104L.

[00047] Each guard tab 120A, 120B extends rearwardly beyond the distal or rearmost ends 116A of the busbar mounting legs 116 an extension distance El (FIG. 4; z.e., along the axis H-H) In some embodiments, the extension distance El is at least 8.7 mm, in some embodiments is at least 17 mm and, in some embodiments is in the range of from about 8.7 mm to 20 mm.

[00048] The rear faces of the busbars LI, L2, L3 define a busbar rear plane PB (FIG. 4). When mounted on the busbars LI, L2, L3, each guard tab 120A, 120B extends rearwardly beyond the busbar rear plane PB a set off or guard distance E2 (FIG. 4; /.< ., along the axes H-H and D-D) In some embodiments, guard distance E2 is at least 5 mm, in some embodiments is at least 16.7 mm, in some embodiments, at least 21.7 mm, and, in some embodiments is in the range of from about 5 mm to 40 mm.

[00049] Each guard tab 120A, 120B extends across the width of the base module 102 a guard tab width W1 (FIG. 5; z.e., along the axis G-G). In some embodiments, the guard tab width W1 is at least 80 percent of the width W2 (FIG. 5) of the base module 102, in some embodiments is at least 100 percent of the width W2 of the base module 102 and, in some embodiments is in the range of from about 50 to 100 percent of the width W2 of the base module 102. In some embodiments, the guard tab width W1 is at least 32.6 mm and, in some embodiments is in the range of from about 18 mm to 36 mm. In some embodiments, the guard tab width W1 is about 2 TE.

[00050] Two ground connector ports 130G are defined in the lower end 104B of the base housing 110. Two neutral connector ports 130N are also defined in the lower end 104B of the base housing 110 laterally beside the ports 130G. Two screw drive ports 136 are located on the front of the base housing 110 over the ports 130G and 130N, respectively.

[00051] The base electrical circuit 140 includes a gas discharge tube (GDT) 142, an electrically conductive neutral bridge busbar 144, an electrically conductive ground bridge busbar 146, three busbar contact assemblies 150, a neutral clamp connector 160N, and a ground clamp connector 160G.

[00052] The neutral bridge busbar 144 includes three electrical terminal sockets 144A, each associated with a respective one of the contact slots 124.

[00053] Each busbar contact assembly 150 (FIG. 9) includes an electrically conductive module/busbar connection busbar 152, an opposing metal contact member 153, a retention clip 155, and a reinforcing spring 154. Each module/busbar connection busbar 152 includes a terminal socket 152A, a midsection or contact section 152C, and a distal end section 152B. Each of the terminal sockets 152A is aligned and associated with a respective one of the contact slots 124, so that each seat 122 includes one terminal socket 152A and one terminal socket 144A.

[00054] Each contact section 152C is positioned and exposed on the rear side of the respective busbar mounting slot 126 to make physical and electrical contact to the respective busbar LI, L2, L3 received in the slot 126. The leg 116, the distal end section 152B, and the contact section 152C can collectively form the busbar mounting slot 126. The connection busbar 152 and the reinforcing spring 154 can elastically deflect when the busbar LI, L2, L3 is inserted to maintain good contact. However, it will be appreciated that other busbar mounting configurations or structures may be used in accordance with other embodiments.

[00055] The locking mechanism 170 (FIG. 7) includes a lock member 172, a pair of springs 174, and a release handle 176. The lock member 172 has a stepped rear edge 172A. The release handle 176 is disposed in a front-facing recess 128 defined in the left lateral section 106J. The release handle 176 may be pivotally connected to the lock member 172. The spring 174 biases the lock member 172 in a rearward direction D4. The release handle 176 can be lifted and pulled in a forward direction D3 to pull the lock member 172 in the forward direction D3.

[00056] The remote signaling system 158 includes a position sensor switch 158 provided at each module receiving seat 122. The switch 158 includes a displaceable pin 158A that is spring loaded to project into the seat 122. Each position sensor switch 158 is connected to a remote signal connector 158B. For clarity, the wires that connect the switches 158 to the connector 158B are not shown in the figures.

[00057] The ground clamp connector 160G and the neutral clamp connector 160N may be constructed and operate in the same or similar manner. Accordingly, it will be appreciated that the description herein of the ground clamp connector 160G likewise applies to the neutral clamp connector 160N.

[00058] With reference to FIGS. 10 and 11, the ground clamp connector 160G includes a connector body 162, a cage member 164, a threaded member 166, and a cable guard member 168. The clamp connector 160G defines a front cable socket 169F and a rear cable socket 169R. The front cable socket 169F is located forward of the rear cable socket 169R (along the heightwise axis H-H). The cable sockets 169F, 169R each open from the lower end 104B along the axis F-F.

[00059] In some embodiments, the threaded member 166 is a screw, as shown. The screw can be differently configured.

[00060] The connector body 162 is electrically conductive. The connector body 162 includes a terminal portion or tab 162A and a cable engagement portion or tab 163. The connector body 162 is formed of an electrically conductive material. In some embodiments, the connector body 162 is formed of metal. Suitable metals may include alloys of copper or CuZn and/or Sn. In some embodiments, the connector body 162 is unitary and, in some embodiments, the connector body 162 is monolithic.

[00061] The cage member 164 includes a pair of opposed side walls 164A, a rear wall 164B, and a front wall 164C defining a cage cavity 164E. A threaded through hole 164D is defined the top wall 164C. Screw threads 165 are formed on the inner surface of the hole 164D

[00062] The cage member 164 is electrically conductive. In some embodiments, the cage member 164 is formed of metal. Suitable metals may include alloys of copper such as CuZn or alloys of iron. In some embodiments, the cage member 164 is unitary and, in some embodiments, the cage member 164 is monolithic. In some embodiments, the cage member 164 is formed from single sheet of metal that is bent to the shape of the cage member 164. [00063] The threaded member 166 includes a threaded shank 166A and a drive head 166B. The drive head 166B serves as a connector actuator to clamp and release cable ends.

[00064] The cable guard member 168 includes an anchor feature 168A, a connecting section 168B, and a cable engagement tab 168C. The cable guard member 168 is electrically conductive. In some embodiments, the cable guard member 168 is formed of metal. Suitable metals may include alloys of copper such as CuZn or alloys of iron. In some embodiments, the cable guard member 168 is unitary and, in some embodiments, the cable guard member 168 is monolithic. In some embodiments, the cable guard member 168 is formed from single sheet of metal that is bent to the shape of the cable guard member 168.

[00065] The cage member 164 encircles the cable engagement tab 163 of the connector body 162. The screw 166 extends into or through and is threadedly mated with the threaded hole 164D. The cable guard member 168 is mounted on the screw 166 for axial movement therewith. The cable engagement tab 168C is positioned over and in contact with the leading end of the screw 166. The cable engagement tab 163 partitions the cage cavity 164E into the front cable socket 169F and the rear cable socket 169R.

[00066] In use, a ground cable CG can be inserted into the front cable socket 169F and/or the rear cable socket 169R. More particularly, depending on the user’s needs, a cable CG can be inserted into the front cable socket 169F only (and the rear cable socket 169R left empty), a cable CG can be inserted into the rear cable socket 169R only (and the front cable socket 169F left empty), or a first cable CG can be inserted into the front cable socket 169F and a second cable CG can be inserted into the rear cable socket 169R (so that both sockets 169F, 169R are occupied by cables CG).

[00067] The screw 166 is then rotated to drive the screw 166 into the cage member 164 through the hole 164D thereby pulling the cage member 164 in a direction D6. In that way, the rear wall 164B and the tab 163 are pulled together to reduce the height of the rear cable socket 169R. Also, in that way, the leading end of the screw 166 and the cable engagement tab 168C are driven toward the tab 163 to reduce the height of the front cable socket 169F.

[00068] As a result, if a cable CG is inserted into the front cable socket 169F, it is compressively captured between the screw 166 and the tab 163. If a cable CG is inserted into the rear cable socket 169R, it is compressively captured between the wall 164B and the tab 163. If cables CG are inserted into both sockets 169F, 169R, they are compressively captured between the screw 166 and the tab 163 and between the wall 164B and the tab 163, respectively. Because the cage member 164 floats on the tab 163, the cage member 164 and the screw 166 can adjust to balance the compressive load applied to the cable ends CG in the sockets 169F, 169R to ensure that the cable or cables are properly loaded regardless of which socket or sockets are occupied 169F, 169R. The contact portions 164B, 163, 168C form direct mechanical and electrical connections between the cable(s) CG and the connector 160G

[00069] In some embodiments, each socket 169F, 169R is sized to receive and clamp a cable having a cross-sectional area of at least 25 mm ² . Accordingly, each connector 160G, 160N can receive and clamp two 25 mm ² cables at once.

[00070] The SPD modules 200 may be identical or may be different from one another in construction. The SPD modules may be constructed and operate in the same or similar manner to the SPD modules disclosed European Patent No. 3401931 (Attorney Docket No. 9360.34. EP), which is incorporated herein by reference, for example. An example one of the SPD modules 200 is described hereinbelow and it will be appreciated that this description may likewise apply to the other SPD modules 200.

[00071] The SPD module 200 (FIGS. 1, 12 and 13) has a front end 202F and an opposing rear end 202R. The SPD module 200 includes a module housing 210, an SPD clamping element subassembly 221, a thermal disconnector mechanism 238, a first electrical contact terminal 232, a second electrical contact terminal 236, a local status indicator mechanism 240, and a remote status indicator mechanism 242. These components are each integral to the SPD module 200. The SPD module 200 has a primary axis J-J. The SPD module 200 is configured to be inserted into the seat 122 in an insertion direction along the primary axis J-J.

[00072] The housing 210 includes laterally opposed side walls 212 and a front wall 214. The housing 210 defines an internal chamber or cavity 216 enclosing or containing the SPD clamping element subassembly 221, the thermal disconnector mechanism 238, and the indicator mechanisms 240 and 242.

[00073] The local status indicator mechanism 240 includes an indicator 240A and a front indicator opening or window 240B provided on the front wall 214. The indicator mechanism 240 may serve to visually indicate a change in status of the module 200 through indicator window 240B, as discussed below.

[00074] The terminals 232, 236 project rearwardly from the housing 210. A remote monitor hole 243 is also provided in the rear wall of the housing 210.

[00075] The housing 210 may be formed of any suitable material or materials. In some embodiments, the housing 210 is formed of a rigid polymeric material. Suitable polymeric materials may include polyamide (PA), polypropylene (PP), polyphenylene sulfide (PPS), or ABS, for example.

[00076] The SPD clamping element subassembly 221 may include one or more overvoltage clamping elements. In some embodiments, the overvoltage clamping element(s) includes one or more varistors. The SPD module 200 may further include a gas discharge tube (GDT) (not shown in the illustrated embodiment). The varistor(s) and the GDT may be viewed together as an overvoltage protection circuit. The overvoltage clamping element may be a transient voltage suppressor (TVS) such as a TVS-diode (e.g., a silicon avalanche diode (SAD)).

[00077] In some embodiments and as shown, the overvoltage clamping element subassembly 221 includes a varistor 220 (as a first overvoltage clamping element), a GDT 222 (as a second overvoltage clamping element), a first electrode 230, a second electrode 234, and a third electrode 235. The first electrode 230 includes or is connected to the first terminal 232, and the second electrode 234 includes or is connected to the first terminal 236. The third electrode 235 connects the varistor 220 to the GDT 222.

[00078] The varistor material of the varistor 220 may be any suitable material conventionally used for varistors, namely, a material exhibiting a nonlinear resistance characteristic with applied voltage. In some embodiments, the varistor 220 is a metal oxide varistor (MOV). In some embodiments, the resistance becomes very low when a prescribed voltage is exceeded. The varistor material may be a doped metal oxide or silicon carbide, for example. Suitable metal oxides include zinc oxide compounds.

[00079] During use or operation, the thermal disconnector mechanism 238 is operative to electrically disconnect the terminal 232 from the terminal 236 (/.< ., creating an open circuit between the terminals 232, 236) in response to an overheating event in the module 200. The overheating event may be caused by a failure (e.g., end of life failure) of the varistor 220, for example.

[00080] The actuation of the thermal disconnector mechanism 238 also releases the spring loaded pin 158A (through the hole 243), thereby actuating or changing the state of the switch 158. The change of state of the switch 158 is transmitted to a remote monitoring system via the remote signal connector 158B.

[00081] The actuation of the thermal disconnector mechanism 238 also actuates the local status indicator mechanism 240 to displace the indicator 240A into a location visible through the window 240B. This provides a visual alert or indication on the SPD module 200 so that an operator can readily determine that the SPD module 200 has assumed its open circuit configuration or state.

[00082] According to some embodiments, each clamp connector 160G, 160N, and each set of connector ports 130G, 130N has a width W4 (FIG. 5; along the lateral axis G-G) that is 1 TE or less. As used herein, “1 TE” means 17.5 mm +/- 0.5 mm.

[00083] According to some embodiments, the left lateral section 106J of the base module 102 has a width W5 (FIG. 6; along the lateral axis G-G) that is 1 TE or less. According to some embodiments, the right lateral section 106K of the base module 102 has a width W6 (FIG. 6; along the lateral axis G-G) that is 1 TE or less. According to some embodiments, the base module 102 has a full width W7 (FIG. 6; along the lateral axis G-G) that is 2 TE or less (where 2 TE is twice 1 TE). According to some embodiments, the upper right section 106U and the lower right section 106V of the base module 102 each have a width W8 (FIG. 6; along the lateral axis G-G) that is 2 TE or less.

[00084] According to some embodiments, each SPD module 200 has a width W9 (FIG. 6) that is 1 TE or less.

[00085] The SPD system 10 and the SPD assembly 100 may be used as follows in accordance with methods of the present invention to form the surge protective electrical installation 11.

[00086] With the front cover 44 opened or removed, the base module 102 is mounted on the busbars 60. The base module 102 is pushed rearward and down so that the busbars LI, L2 and L3 are each received and seated in a respective one of the slots 126, as shown in FIG. 1. During this operation, the lock member 172 is displaced in direction D3 by the busbar L2 and then fully or partially released when the busbar L2 is fully seated in the slot 126, thereby allowing spring 174 to return the lock member 172 in the direction D4. The base module 102 is thereby locked or latched onto the busbars 60 automatically, screwlessly, and tool-lessly (i.e., without the need for or use of tools).

[00087] Before or after installing the base module 102 on the busbars 60, the cables CN, CG are mechanically and electrically connected to the base module 102 by clamping the connectors 160N and 160G onto the cables CN and CG, respectively. As discussed above, each connector 160N, 160G may be used to receive and clamp a single cable CN or a single cable CG (using one of the ports 130G or 130N and sockets 169F, 169R), or may be used to receive and clamp a two cables CN or two cables CG (using both of the ports 130G or 130N and sockets 169F, 169R). [00088] The remote monitoring system 30 can be electrically connected to the SPD assembly 100 at the connector 158B.

[00089] Before or after installing the base module 102 on the set of busbars 60 and/or connecting the cables CN, CG to the base module 102, the SPD modules 200 are inserted into their respective seats 122. The terminals 232, 236 are received in the slots 124 to make electrical contact with the terminal sockets 152A and 144A. The SPD modules 200 may be locked in place using the locking mechanisms 202.

[00090] Before or after installing the SPD modules 200 into their seats 122, the front cover 44 is installed over the enclosure chamber 42 and the base module 102. The front cover 44 is positioned in its closed position, wherein the access opening 46 overlies (along the depthwise axis D-D) the exposed or open region 42A of the chamber 42, and the panel 45 overlies (along the depthwise axis D-D) the covered or closed region 42B of the chamber 42. The base module 102 is aligned (along the axes B-B and C-C) with the closed front cover 44 such that the panel 45 overlaps (along the axis D-D) the left lateral section 106J, the upper right section 106U, and the lower right section 106L. The base module 102 is also align with the access opening 46 of the closed front cover 44 such that the right lateral section 106L is overlapped by or within the boundary of the access opening 46. The module seats 122 and the SPD modules 200 are thereby exposed through the access opening 46 along the depthwise (front-rear) axis D-D. In some embodiments, the SPD modules 200 project forwardly through and beyond the access opening 46 and, in some embodiments project through the access opening 46 and forwardly beyond the panel 45.

[00091] The front face of the left lateral section 106 J may be located closely adjacent the overlying panel 45. In some embodiments, the gap between the front face of the left lateral section 106J and the panel 45 has a width W9 (FIG. 5) less than 0.5 mm, in some embodiments, in the range of from about 0.1 mm to 20 mm, and in some embodiments, in the range of from 0.1 mm to 0.5 mm.

[00092] The sections 106J, 106U, and 106L are thus covered, hidden and shielded by the front cover 44. Meanwhile, the SPD modules 200 are exposed and accessible through the access opening 46.

[00093] The user may thereafter remove and replace one or more of the SPD modules 200 without removing the front cover 44.

[00094] The user can also open the front cover 44 to remove the base module 102 (and the SPD modules 200, if installed) from the busbars LI, L2, L3. Upon opening the front cover 44, the left lateral section 106J is exposed. The user can access and operate the lock release actuator 176, pull the base module 102 off the busbars LI, L2, L3, and disconnect the cables CG, CN from the connectors 160G, 160N.

[00095] Advantageously, when the front cover 44 is closed, the configuration of the SPD assembly 100 and the configuration of the electrical installation 11 (including the SPD assembly 100, the busbars 60 and the front cover 44) prevents access to the lock release 176 and the connectors 160G, 160N while allowing convenient access to the SPD modules 200. The user can remove and install the SPD modules, as well as view the indicator windows 240B to determine the statuses of the SPD modules 200.

[00096] The configuration of the SPD assembly 100 and the configuration of the electrical installation 11 also makes efficient, space-saving use of the space within the enclosure 40. Typically, the space behind the panel 45 occupied by the sections 106J, 106U, and 106L is not used. The configuration of the SPD assembly 100 allows the right lateral section 106K to occupy the open space while utilizing the extra space to house the components and connector ports of the SPD assembly 100 that need not be exposed.

[00097] The guard tabs 120A, 120B project rearwardly beyond the busbars LI, L2, L3 from either end by an extended distance. The guard tabs 120 A, 120B can thus prevent or inhibit the user from touching a live busbar LI, L2, L3 with their finger or an object. In particular, the guard tab 120B prevents or inhibits the user from touching a live busbar LI, L2, L3 with a cable CG, CN while attempting to insert the cable CG, CN into a connector 160G, 160N

[00098] While the SPD assembly 100 includes three SPD modules 200 and is configured for direct mounting on three busbars with direct cable connections to neutral and ground, other configurations may be provided in accordance further embodiments of the inventions. For example, an SPD assembly according to some embodiments may include five removable and replaceable SPD modules 200 (and five corresponding seats 122) and be configured for direct mounting on five busbars (connected to three phase lines, a neutral line, and a ground line). An SPD assembly according to further embodiments may include only two removable and replaceable SPD modules 200 (and two corresponding seats 122) and be configured for direct mounting on a two-pole busbar system, for example.

[00099] FIG. 14 is a schematic diagram illustrating the electrical circuit of the SPD assembly 100. FIG. 15 is a schematic diagram of an alternative SPD assembly 100' wherein the GDT 222 is omitted from the base module 102.

[000100] Many alterations and modifications may be made by those having ordinary skill in the art, given the benefit of present disclosure, without departing from the spirit and scope of the invention. Therefore, it must be understood that the illustrated embodiments have been set forth only for the purposes of example, and that it should not be taken as limiting the invention as defined by the following claims. The following claims, therefore, are to be read to include not only the combination of elements which are literally set forth but all equivalent elements for performing substantially the same function in substantially the same way to obtain substantially the same result. The claims are thus to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, and also what incorporates the essential idea of the invention.