GB2330243A

GB2330243A - Earthing and attaching duct to junction box

Info

Publication number: GB2330243A
Application number: GB9815396A
Authority: GB
Inventors: Richard Lee Arthur; Brian Amedee Nauman
Original assignee: Walker Systems Inc
Current assignee: Walker Systems Inc
Priority date: 1997-08-06
Filing date: 1998-07-15
Publication date: 1999-04-14
Anticipated expiration: 2018-07-15
Also published as: GB9815396D0; PL327680A1; CA2243792A1; GB2330243B

Abstract

A junction box 16 for an in floor electrical raceway system includes a housing 18 having duct openings 34,36 for connecting ducts 80 in communication with the hollow interior 32 of the housing 18. The ducts 80 are secured in the openings by metallic clips 84 which are inserted into the housing 18 subsequent to positioning of the duct 80 within the duct opening 34,36. The metallic clips 84 have serrated legs 108 which engage against the side wall of the duct 80 simultaneously to earth and bias the duct 80 within the duct opening 34,36.

Description

IMPROVED JUNCTION BOX FOR IN FLOOR WIRE MANAGEMENT SYSTEM Floor wiring distribution systems are designed to be imbedded in a concrete floor for the purpose of providing a raceway for wires and cables from their originating panel to their point of use. One type of raceway system employs a combination of feeder ducts and distribution ducts. These ducts are interconnected by junction boxes which serve as a directional change and pull point for the wires contained in the floor system.

These junction boxes include access covers which can be removed to access the interior of the boxes after the concrete floor has been poured.

Known junction boxes suffer from several drawbacks, specifically, these junction boxes are not readily modifiable to accommodate a variety of floor thicknesses, duct sizes and duct patterns. These junction box designs also employ systems for connecting the ducts to the junction box which are time consuming and/or ineffective.

Electrical codes require that the different services, e.g. power, telephone and data, remain separated from each other as they are routed in floor distribution system. For this purpose, such floor boxes typically incorporate wiring tunnels for maintaining separation between the various services within the box.

However, known wiring tunnels are cumbersome to manufacture and install, and are not easily modifiable to accommodate a varying number of services.

This invention relates generally to junction boxes for use with an electrical raceway system designed to be placed in a floor, and more particularly, to a junction box assembly which is readily adaptable for use with a variety of duct patterns and a variety of floor thicknesses.

According to the present invention a junction box comprises a housing having at least one duct opening disposed therethrough for receiving at least one duct. A metal clip is insertable into the housing for simultaneously ground and resiliently grip a duct positioned within the duct opening. The metal clip includes at least one serrated leg which engages against a side wall of said duct to simultaneously grip and ground the duct within the opening. Preferably, a pair of such metal clips are inserted on opposite sides of the duct opening. As the second clip is inserted into the housing, its serrated leg comes into contact with the sidewall of the duct. As the second clip is driven into the housing, the duct is compressed between the serrated outer legs of the opposing metal clips, thereby simultaneously grounding and gripping the duct.

Examples of the present invention will be described in accordance with the accompanying drawings, in which: Figure 1 is a perspective view of a wiring distribution system incorporating a junction box according to the present invention; Figure 2 is a perspective view of a junction box according to the present invention with the cover plate assembly removed from the lower housing; Figure 3 is a perspective view of the junction box with the top rail removed to expose the housing interior; Figure 4 is an enlarged perspective view of a portion of Figure 3 showing a duct spacer which is employed in the junction box; Figure 5 is a top view of the duct spacer of Figure 4; Figure 6 is a perspective view of a corner conduit adapter for use with the junction box of Figure 1; Figure 7 is a top view of another duct spacer employed in the junction box; Figure 8 is a partial perspective view illustrating the manner for connecting a duct within a duct opening in accordance with the present invention; Figure 9 is a reverse angle view of Figure 8 (without the duct being shown); Figure 10 is a partial perspective view showing the components of Figure 8 upon completion of the assembly process; Figure 11 is a partial perspective view illustrating the manner- for installing a duct using a duct opening reducer; Figure 12 is a reverse angle view of Figure 11; Figure 13 is a partial perspective view showing the components of Figure 11 upon completion of the assembly process; Figure 14 is a partial sectional view along line A A of Figure 1, wherein the cover plate assembly has been installed; Figure 15 is a front partial section view similar to Figure 14, wherein the tile spacer has been removed to lower the height of the cover plate; Figure 16 is a perspective view of the junction box of the present invention employing a round cover plate; Figure 17 is an exploded perspective view of the round cover plate assembly of Figure 16; Figure 18 is a perspective view of the tunnel partition of the present invention; Figure 19 is an exploded perspective view illustrating a side rail extension assembly which can be used to increase the depth of the junction boss; Figures 20 and 22 are partial perspective views further illustrating the side rail extension assembly; Figure 23 is a perspective view illustrating wire routing within the junction box when the wiring tunnel is installed; and, Figure 24 is a perspective view illustrating the expandable nature of the tunnel assembly of Figure 18.

Referring to Figure 1, the junction box according to the present invention is designed for use with an in floor wiring distribution system 10 which is imbedded in a concrete floor for the purpose of providing a raceway for wires and cables from their originating panel 11 to their point of use. The raceway system 10 employs a combination of feeder ducts 12 and distribution ducts 14. As can be seen from Figure 1, the feeder ducts 12 and distribution ducts 14 run generally perpendicular to each other. Junction boxes 16 interconnect these ducts to provide directional changes and pull point for the wires contained in the floor system. The junction boxes 16 incorporate removable cover plates which provide access to the interior of the boxes after the concrete floor has been poured.

Referring now to Figures 2 and 3, the junction box 16 includes a lower housing 18 and a cover plate assembly 20 which is adapted to be mounted on the top of the lower housing. The lower housing 18 includes a base plate (or pan) 22 and a plurality of side walls 24a-d extending upwardly from the periphery of the base plate.

A top rail 26 extends inwardly from the top of the side walls, and a side rail 30 extends upwardly from the top rail, between its inner and outer edges. The base plate 22, side walls 24, and top rail 26 define a hollow interior 32.

Each of the side walls 24a-d includes at least one duct opening adapted to receive a duct of a predetermined size for permitting the duct to communicate with the hollow interior of the lower housing. In the illustrated embodiment, each side wall 24a-d has a respective first duct opening 34a-d and a respective second duct opening 36a-d. Preferably, each of the first duct openings 34a-d is sized to accommodate a No. 2 duct which is 3 1/8" (79.4 mm) wide and 1 1/4" (31.8mm) deep (high) with a cross sectional area of 3.34 square inches (2154.8 sq. mm), while each second duct opening 36a-d is preferably sized to accommodate a No.

4 duct which is 6 1/2" (165.1 mm) wide and l 1/2" (38.1 mm) deep with a cross sectional area of 8.72 sq. in.

(5625.8 sq. mm).

The first duct openings 34a-d include a lower wall 41a-d, as is shown in Figure 3. Duct steps 40 are mounted behind the lower walls 41a-d to support the No.

2 ducts such that their top wall is level with the top wall of the No. 4 ducts. In the illustrated embodiment, the duct steps 40 have a thickness of approximately 1/4" (6.3 mm). The duct steps 40 are secured to the base plate 22 of the lower housing 18 using two sided adhesive tape (not shown). As will be appreciated, other means, such as assembly screws, could also be used for this purpose. The duct steps 40 are also employed when a reducer 110 is used to mount a No.

2 duct in a No. 4 duct openings, as is described below in connection with Figures 11-13.

Although the junction box 16 is shown having two duct openings per side wall, it will be appreciated that the size and number of openings per wall can vary.

Currently, the junction box can be expanded to accommodate up to five dusts per side wall. As will be appreciated, the size of the junction box typically must increase as the number of ducts increases. However, the basic design of the junction box does not change.

External leveling feet 42 are connectable to the four corners of the lower housing 18 for adjusting the height of the junction box 16 prior to pouring of the concrete floor. Each leveling foot 42 includes a base 44 and a leveling screw 46 which extends upwardly from and is rotatably connected to the base. The leveling screw 46 threads into a reciprocal aperture 48 in the corner of the base plate 22, externally of the side walls 24. The top of the leveling screw 46 may be slotted for receiving the head of a screwdriver.

Alternatively, the top of the leveling screw 46 may incorporate a bolt head which can be engaged with a wrench or socket.

Adjacent duct openings (e.g., 34a and 34b) are separated by vertical side wall sections 52. As can be seen in Figure 3, duct spacers 54 are mounted about the vertical side wall sections 52. The duct spacers 54 are formed of non-conductive material such as plastic and are provided to maintain a predetermined spacing between adjacent ducts (preferably at least one inch) and to form non-abrasive pull points for the wires that are routed through the duct openings 34, 36.

Referring additionally to Figures 4 and 5, the duct spacer 54 has legs 56 which are designed to snap in place around the side wall sections 50 during assembly of the junction box. For this purpose, the legs 56 include opposing recesses 58 which are sized for receiving the vertical side wall section 50. The recesses are defined by an outer flange 60 and an inwardly extended portion 62 of the leg 56. The duct spacer 54 is mounted in place by positioning it within the housing interior 32 and aligning its legs 56 with the edges of a vertical side wall section 52. The spacer 54 is then pushed towards the exterior of the housing (i.e., in the direction of the arrow 60 in Figure 4). As the distal ends of the legs 56 engage against the edges of the side wall section, they are biased away from each other and they begin to slide around the edges of the side wall section 52. The distal ends of the legs are beveled to ease this process. The legs 56 are pushed through the duct openings until the inner faces of the flanges 60 extend past the outer face of the side wall section 50. At this point, the legs 56 snap back towards each other, locking the vertical side wall section 50 into the recesses 58.

Referring additionally to Figure 6, the body assembly also includes corner openings 64 at the junctions of adjacent side walls (e.g. 24a and 24b).

The corner openings 64 are adapted to receive conduit couplers 66 for connecting standard EMT conduit to the junction box. The conduit coupler 66 has a base 68 sized for insertion into the corner opening. The coupler 66 is secured within the corner opening by a set screw 70. A boss 72 extends from the front face of the conduit coupler and defines an opening 74 sized and shaped to receive a predetermined size of EMT conduit.

As will be appreciated, the coupler can be sized to accommodate a wide range of conduit diameters. A set screw 76 secures the conduit (not shown) within the aperture 74. Cover plates 78 (see Fig. 1) are provided for sealing the corner openings if the conduit coupler is not employed.

Vertical side wall sections 52 also separate the side wall duct openings from the corner openings. Nonmetallic corner spacers 74 (see additionally Figure 7) snap into place around these side wall sect ions in the manner described above.

The manner in which a duct is secured to the junction box 16 will now be explained with reference to Figures 8 to 10. Figures 8 to 10 illustrate connection of a number 4 duct (identified with reference number 80) to one of the larger second duct openings 36. It will be appreciated that the same process is employed to secure the No. 2 ducts to the (smaller) first duct openings 34. It should also be noted that Figures 8-10 show three duct openings. For illustration purposes, the center opening has been designated as one of the second openings 36, while the outer openings have been designated as first duct openings 34. After the duct 80 is cut to its required length, it is inserted into the duct opening 36. Vertical ribs 82 formed on the duct spacers 54 function as duct stops for controlling the distance the duct 80 is inserted into the opening 36.

These vertical ribs 82 also serve as a grometted surface for preventing abrasion of the wires carried by the ducts when the wires are being pulled through the ducts during assembly.

Metal clips 84 are provided for securing the duct in place and for providing ground continuity. Each clip 84 has a pair of serrated outer legs 86, 88 and a bifurcated middle leg 90 which extend downward from an upper portion 92 of the clip. The clips 84 are adapted for insertion into reciprocal triple slot openings 94 formed in the top rail 26 of the lower housing at the opposite ends of the duct openings (i.e. at the location of the vertical wall sections 52). As can be seen in Figures 8 and 9, each triple slot opening 94 has a middle slot 96 surrounded by two outer slots 98, 100.

The sidewall has been cut away in Figure 8 to show the triple slots. The slots 96-98 are spaced to align with the legs 86-88 of the metallic clips 84. Moreover, the middle slot 96 is positioned to align generally with the center of the vertical side wall section 52, while the outer slots 98, 100 are positioned to extend over the adjacent duct openings (e.g., the left duct opening 34 and the center duct opening 36 in Figure 8). Vertical grooves 102 formed in the plastic spacers 54 align with the outer slots 98, 100 in the triple slot openings 94.

The grooves 102 serve as a channel to guide and captivate the outer legs 86, 88 of the metal clip 84.

Installation of duct is as follows. The duct 80 is inserted in the duct opening 36 until it abuts the stops 82 formed on the duct spacers 54. Once the duct 80 is fully inserted into the opening, a metal clip 84 is installed in the triple slot opening 94 on one side of the duct opening. A second metal clip 84 is then inserted into the triple slot opening 96 on the opposite side of the duct opening. If multiple ducts are to be attached to the junction box, all of the ducts are inserted into the duct openings prior to installing the metal clips 84.

As can be seen in Figure 8, the bottom ends of the clip legs 86-90 are rounded or beveled to ease their insertion into the slots 96-100. The middle slot 96 of the triple slot 94 is narrower than the width of the bifurcated middle leg 90 so as to form a friction fit therewith. As the clip legs 86-90 are inserted into the slots 96-100, the bifurcated middle leg 90 forms a resistance to further downward travel as its outer edges are squeezed inwardly by the edges of the middle slot 96. This interference fit maintains ground continuity between the clip 94 and the body of the box 16.

The outer slots 98, 100 extend laterally beyond the edges of the duct opening 36 such that the space 106 between the slots on opposite sides of an opening is less than the width of the duct which is to be inserted into the opening. Hence, as the second clip 84 is forced further into the slot 94, the serrated edges 108 of the clip's outer leg 86 (or 88) comes into contact with the side wall 110 of the duct 80. At this point, a hammer or other tool is used to drive the clip 84 the remaining distance into the slots. As this clip is driven into place, the side walls 110 of the duct are compressed between the legs of the metal clips 84. The side wall of the duct opposite the driving clip is forced into the serrations of the previously installed metal clip. At the same time, the serrated edge 108 of the driving clip abrades the side of the duct. Once installed, the outer legs of the clips 84 exert a compressive force against side walls of the duct, thereby creating a solid mechanical connection, as well as ground continuity. Figure 10 shows the duct upon installation.

Reducers 110 are provided to permit one of the smaller sized ducts 111 to be mounted in the larger, second duct openings 36. The manner in which these reducers 110 function will now be explained with reference to Figures 11-13. The reducer 110 consists of a generally U-shaped body portion 113 having first and second opposing side walls 112, 114 and a back wall 116 extending between the first and second side walls. An elongated leg 118 extends from the lower end of the first side wall 112 and is generally parallel to the back wall 116. A serrated lip 120 extends from the front edge of the first wall 112 and in the same direction as the elongated leg 118.

The distal end 122 of the elongated leg 120 is slid into (and captivated by) the vertical slot 102 in one of the plastic spacers 52. The body 113 of the reducer 110 is then rotated towards the duct opening, i.e., in the direction of arrow 122. The body 113 of the reducer 110 has a height which is substantially equal to that of the duct opening. Serrations 124 formed on the top edge of the second side wall 114 extend beyond the height of the duct opening. As the reducer 110 is inserted (forcibly) into the duct opening (using a hammer, for example), these serrations 124 abrade the top wall of the duct opening. This friction fit mechanically secures the reducer 110 to the junction box and also provides an excellent ground connection. It will be appreciated that the serrations 124 could be formed on the other walls 112, 116 as well as on the bottom edges of any of the walls 112, 114, 116.

A duct step 40 is mounted in the opening behind the elongated leg of the reducer 110. As was explained above, the step is held in place by two sided tape. The duct step serves as a vertical support for the No. 2 duct, ensuring that its top wall aligns with the top walls of the larger (e.g. No. 4) ducts and prevents the lower wall of the duct from exerting excessive force on the elongated leg 118.

The duct 111 is then inserted into the opening until it abuts the stop 82 formed on the duct spacer 54.

Once the duct 111 is in position, a metal clip 84 is driven into the tipple slot opening 94 opposite the serrated lip 120. (Note: a metal clip is also driven into the triple slot which is adjacent the body portion 113 of the reducer.) As the metal clip 84 is driven into place, its outer leg 88 comes into contact with the sidewall of the duct 111. The side walls of the duct 111 are compressed between the serrated lip 120 on the reducer 110 and the serrated leg 88 of the metal clip 84. As this occurs, the side wall of the duct opposite the metal clip 84 is forced into the serrated lip 120 of the reducer 110. At the same time, the serrated leg 88 of the clip 84 abrades the side of the duct, thereby creating a solid mechanical connection, as well as ground continuity.

The junction box 116 can accommodate both square and round cover plates. Referring to Figures 2, 14 and 15, the square cover plate assembly 130 consists of a cover plate 132, a cover plate trim rail 134 and a vertical partition or divider 136. The partition 136 is secured to the trim rail 134, e.g. by fasteners or welding, and is positioned to align against a vertical partition of the tunnel when the cover assembly 130 is mounted on the lower housing 18. The cover plate 132 fits within the periphery of the trim rail 134 and is supported by a flange 138 which extends inwardly from lower edge of the trim rail. (See Figs. 14 and 15).

The trim rail 134 is generally square and is sized to fit within the periphery of the housing side rail 130 of the lower housing. The trim rail 134 is vertically supported leveling screw assemblies 140 which are mounted at the four corners of the lower housing 18.

Each leveling screw assembly 140 includes a leveling screw 142 and a leveling washer 144 mounted about the top of the screw 142, adjacent its head. At least one locking washer 146 (preferably two) is disposed between the leveling washer 144 and the head of the leveling screw 142. The support washer 144 is threaded onto the leveling screw 142 and is tightened in place with a predetermined torque to prevent its rotation relative to the screw 142. It will be appreciated that other methods, such as spot welding, could be used to affix the support washer 144 to the leveling screw 142.

The leveling screw 142 in turn threads into a support post 148 which extends upwardly from the bottom pan 22 of the housing. The support post 148 is affixed to the base plate 22 by welding, for example.

The cover plate includes holes which align with the leveling screws 142 to permit the height adjustment after the cover plate 132 is installed. Once the cover plate is properly leveled, the cover plate 132 is secured in place by assembly screws 152 which insert through the mounting holes 154 in the cover plate and thread into reciprocal apertures 156 formed in the leveling washer 144. In the illustrated embodiment, there are four such holes 156 in each of the leveling washers 144. (See Figure 2). Thus, a maximum of a quarter turn is required to align the one of the holes 156 in the washer 142 with the mounting hole 154 in the cover plate. As is shown in Figure 14, removable tile buttons 160 may be interposed between the cover plate 132 and the cover plate trim rail 134 in applications where carpet is used as the floor covering. If the finish floor is to be tile, the tile buttons 160 are removed (See Figure 15) to lower the top face of the cover plate 132 below the top edge of the cover plate trim rail 134.

Referring to Figure 16 and 17, the round cover plate assembly 164 consists of a round cover plate adapter 166, a round cover plate 168, a cover plate pan 170, a vertical partition or divider 172, and a gasket 174 which is interposed between the cover plate pan and the cover plate adapter. Although only a portion of the gasket 174 is shown, it will be appreciated that the gasket 174 extends around the entire periphery of the circular opening 178 in the cover plate pan 170. The partition is secured to the lower edge of the cover plate pan, e.g. by welding, and aligns against a vertical partition of the tunnel when the cover assembly 164 is installed. The cover plate pan is in turn fixedly secured to the cover plate adapter, e.g. by welding. After the partition is welded to the cover plate pan, the pan is welded to the bottom of the cover plate adaptor to form an integral subassembly.

The cover plate adapter 166 has a circular opening 176 sized to receive the cover plate 168. A circular opening 178 in the cover plate pan 170 aligns coaxially with the opening 176 in the cover plate adapter 166.

The diameter of the opening 178 in the pan 170 is smaller than the diameter of the opening 176 cover plate adaptor 166. As a result, the cover plate pan 170 extends inwardly beyond the opening 176 in the adapter 166 and serves as a vertical support for the cover plate 168.

During installation, the cover plate 168 is secured in place by assembly screws 180 extend through openings 182 in the cover plate 168 and thread into reciprocal openings 184 in the cover plate pan 170.

The cover plate adapter 166 is generally square and is sized for insertion within the periphery of the side rail 30 of the lower housing 18. The cover plate pan 170 is also square, but is slightly smaller than the adapter 166. A side wall 190 extends downward from the periphery of the cover plate pan. The lower edge of the side wall 190 rests upon the leveling washers 144 of the leveling screw assemblies 140. As can be seen in Figure 17, the corners of the pan 170 have cut away sections 152. The cut away sections 192 are generally arcuate, and have a diameter which is less than that of the leveling washers 144. The cut away sections 192 allow assembly screws 152 to extend through the adapter and thread into the reciprocal apertures 156 in the leveling washers 144. These cut away sections 192 also allow the head of the leveling screw 142 to be accessed through apertures formed in the cover plate adapter 166 after the adapter has been secured to the lower housing 18.

Referring to Figures 18 and 23-24, the junction box includes a tunnel assembly 200 for isolating each duct in a multiple duct box to create a continuous raceway through the box in both directions. The tunnel assembly divides the housing into a set of lower passages 204a, 204b which extend across the housing in a first direction 206 and a set of upper passages 208a, 208b which extend across the housing in a second direction 210, perpendicular to the first direction. The tunnel further defines take off areas 212a, 212b each of which interconnects one of the lower passages 204a, 204b with a respective one of the upper passages 208a, 208b.

The tunnel assembly includes a horizontal partition 216, a plurality of lower partitions 218, 219, 220 which extend between the base plate 22 of the housing and the horizontal partition 216, and a plurality of upper partitions 222, 224, 226 which extend upwardly from the horizontal partition 216. The lower partitions 218, 219, 220 extend across the housing in the first direction 206 and, in combination with the horizontal partition 216, define the lower passages 204. In the embodiment shown in Figures 18 and 23, the tunnel assembly has three lower partitions which define first and second lower passages 204a, 204b. The outermost lower partitions 218 and 220 are preferably integrally formed with the horizontal partition 216, e.g. from sheet metal or aluminum. The intermediate lower partition(s) 219 (one shown in Figures 18 and 23) are separately formed from the horizontal partition 216. As is shown in Figure 24, additional lower passages can easily be formed by increasing the number of the intermediate lower partitions 219.

The intermediate lower partitions 219 have a generally T-shaped cross-section and are preferably formed of extruded aluminum. The upper leg of 228 the intermediate partition(s) 219 is secured to the horizontal partition 216 by a plurality of machine screws. The lower leg 230 of the intermediate divider rests on the base plate 22 of the housing. Flanges 234 are formed on the outermost of the lower dividers.

Assembly screws extend through the flanges 234 and into the base plate 22 to secure the tunnel assembly 200 within the lower housing.

The upper partitions 222, 224, 226 extend across the housing in the second direction 216 and, in combination with the horizontal partition 216, define the upper passages 208. The two outermost upper partitions 222, 226 are preferably integrally formed with the horizontal portion 216, e.g. from sheet metal or aluminum. The intermediate upper partition(s) 224 (one shown in Figures 18 and 23) are separately formed from the horizontal partition 216. As shown in Figure 24, additional upper passages 208 can be formed by increasing the number of the intermediate lower partitions, 224. The intermediate upper partition(s) 224 have a similar construction to the lower intermediate partitions 219. The intermediate upper partitions 224 are secured to the upper face of the horizontal partition 216 via a plurality of assembly screws.

As can be seen in Figure 18, the two outermost of the lower partition walls 218, 220 are spaced inwardly from the housing side walls to define a vertical routing passages 240 which interconnect the duct openings 34, 36 with the upper passages 208. These passages are used to route cables 244 between the upper passages 208 and the ducts.

The horizontal partition 216 includes a plurality of cut out sections 246 which define the take off areas 212. Each of the cut out sections 246 connects one of the lower passages 204 with a different one of the upper passages 206. Specifically, in the embodiment illustrated in Figure 23, a first cut out section 246a connects the first upper passage 208a with the first lower passage 204b. Similarly, a second cut out section 246b connects the second upper passage with the second lower passage. As will be appreciated, additional cut out sections are required as the number of passages increases, see, e.g., Figure 24.

For ease of manufacturing, the outermost partitions (upper and lower) do not extend the entire width of the housing. However, it will be appreciated that these walls could extend the full width of the housing, as is illustrated in broken line in Figure 24.

A side rail extension assembly 300 may be used to extend the height of the junction box 18 as may be required in certain applications. The side rail extension assembly 300 consists of four extension rails 302, four leveling screw plates 304 (one shown) and a vertical partition 304. The vertical partition 304 replaces the partitions 136 and 172. It will be appreciated that additional vertical partitions 304 are required as the number of services increases.

Each side rail extension 302 has a closed end slot 308 at one end and an open end slot 310 at the other end. Each leveling screw plates consist of a flat plate 312 having a first leg 314 extending upwardly from one edge and a second leg 316 extending downward from a second edge, adjacent the first edge. The leveling screw plates 304 are used to connect adjacent pairs of the side rail extensions 304 by first inserting the first leg 314 through a closed end slot 310 formed in the end of one of the side rails 304. The second leg 316 is then slid into an open-end slot 310 in the second rail extension 304. An assembly screw extends through an aperture in the second leg 316 and threads into a threaded aperture in the side rail 304. This process is repeated for the remaining three corners of the side rail extension assembly.

The side rail extension assembly 300 is sized to fit around the periphery of the side rail 30 of the lower housing 18. Outwardly extending flanges 320 formed at the lower ends of the side rail extensions rest upon the top rail 26 of the lower housing 18. The side rail extension assembly 300 are secured to the lower housing 18 by assembly screws which extend through the lower flanges 320 and thread into the top rail 24.

When the side rail extension assembly 30 is positioned on the lower housing 18, apertures 324 in the leveling screw plates 304 align with the supports 148.

Depending on the height of the extension rails 302, it may be necessary to extend the height of the support 148 using an extender 328. The extender 328 fits through the aperture 324 in the leveling screw plate 304 (with clearance) and rest on the top of the support post 148.

The leveling screw 142 extends through the extender 328 and threads into the support post 328. As will be appreciated, the length of the leveling screw 142 is dependent on the height of the side rail extension assembly 300.

Claims

CLAIMS: 1. A junction box for interconnecting the ducts of an in floor electrical raceway system, comprising: a housing having at least one duct opening disposed therethrough for receiving at least one duct; and a metal clip insertable into the housing, the clip being arranged to simultaneously ground and resiliently grip a duct positioned within the duct opening upon insertion of the clip into the housing.
2. A junction box as set forth in Claim 1, wherein the metal clip includes at least one serrated leg which engages against a side wall of the duct to simultaneously grip and ground the duct within the duct opening upon insertion of the clip into the housing.
3. A junction box as set forth in Claim 1 or 2, wherein a pair of metal clips are inserted into the housing at opposite sides of the duct openings.
4. A junction box as set forth in any one of the preceding claims, wherein the housing has at least two adjacent duct openings which are separated by a vertical side wall section of a predetermined width.
5. A junction box as set forth in Claim 4, further comprising a non-metallic duct spacer mounted about the vertical side wall section.
6. A junction box as set forth in Claim 5, wherein the duct spacer is adapted to snap in place around the vertical wall section.
7. A junction box as set forth in Claims 5 or 6 wherein, the duct spacers further include vertical flanges which extend into the duct opening and function as a back stop for a duct upon its insertion into the duct opening.
8. A junction box as set forth in any one of Claims 4 to 7, wherein the or each metal clip includes a serrated leg which is positioned to extend into the adjacent duct openings upon the clip's insertion into the housing, the or each serrated leg being arranged to engage against a side wall of a duct positioned in the duct opening to simultaneously grip and ground the duct within the duct opening upon insertion of the clip into the housing.
9. A junction box as set forth in Claim 8 when dependent upon any one of Claims 5 to 7, wherein the duct spacer includes vertical grooves positioned to guide and captivate the serrated legs of the or each metallic clip upon its insertion into the housing.
10. A junction box as set forth in any one of the preceding claims wherein, the housing is generally rectangular.
11. A junction box as set forth in any one of the preceding claims, wherein the housing comprises: a lower housing having a hollow interior, a top opening providing access to the hollow interior and a plurality of duct openings adapted for connecting ducts in communication with the hollow opening; and a cover removably mounted over the top opening of the lower housing.
12. A junction box as set forth in Claim 11, wherein the duct openings are sized to receive ducts of at least two different sizes.
13. A junction box as set forth in Claim 11 or 12, wherein the lower housing includes a base plate, a side wall extending upwardly from the edges of the base plate, and a top rail extending inwardly from the top edge of the side wall, the base plate, side wall and top rail defining the hollow interior in which the side wall defines a plurality of duct openings and wherein the cover assembly is mounted over the top opening of the lower housing for providing access to the housing interior.
14. A junction box as set forth in Claim 13, wherein the junction box is adapted to be installed in a poured concrete floor; and wherein the cover assembly includes a cover plate which is removable after the junction box is installed in a poured concrete floor.
15. A junction box as set forth in Claim 13 or 14, wherein said cover plate is round.
16. A junction box as set forth in Claim 13 or 14, wherein said cover plate is square.
17. A junction box as set forth in any one of the preceding claims, further comprising a levelling means for levelling the cover assembly subsequent to its installation on the lower housing.
18. A junction box as set forth in Claim 17, wherein the levelling means comprises levelling screw assemblies positioned at the four corners of the housing lower portion, each of the levelling screw assemblies comprising a levelling screw which threads into a reciprocal support positioned in the lower housing, the levelling screw carrying a support which engages against the bottom of the cover plate assembly, whereby the cover can be raised and lowered by threading the levelling screw into and out of said boss.
19. A junction box as set forth in any one of Claims 13 to 18, further comprising corner openings formed at the junctions of adjacent side walls, and opening to the hollow interior of the lower housing; and a conduit connector adapted for insertion into the corner openings and defining an opening for receiving an electrical conduit of a predetermined size; and means for securing the conduit connector within the corner opening.
20. A junction box as set forth in any one of the preceding claims, further comprising a duct reducer insertable into the duct opening for reducing the size of the duct opening.
21. A junction box as set forth in Claim 20, wherein the duct reducer includes a serrated edge which faces the duct opening and wherein insertion of the metal clip into the housing compresses the duct between the metal clip and the serrated edge of the duct reducer, thereby simultaneously grounding and gripping the duct within the opening.
22. A junction box substantially as shown in or described with respect to any one of the accompanying drawings.