Shallow Depth Load Center

Abstract

A load center is constructed with line busing disposed entirely between the circuit breakers, without adding depth to the load center enclosure, and positioned to be engaged by circuit breakers that are locked into position by pivoting thereof in planes parallel to the rear wall of the enclosure.

Description

This invention relates to load centers in general, and more particularly relates to an especially shallow depth load center.

In trailers, mobile homes, and houses constructed with 2 .times. 3 studs, the space between wall layers is very narrow, thereby highlighting the need for shallow depth load centers. With this in mind, the instant invention provides a load center construction in which the depth of the panelboard enclosure is controlled by the thickness, rather than the length or width, of the circuit breakers, and the busing is positioned so that it does not add to the enclosure depth.

Accordingly, a primary object of the instant invention is to provide an especially shallow load center.

Another object is to provide a load center construction in which the enclosure depth is controlled by the thicknesses of the circuit breaker.

Still another object is to provide a load center in which line busing does not add to the enclosure depth.

A further object is to provide a shallow depth load center in which line busing consists of two identical straps, each having a stab portions frictionally engageable by four circuit breakers.

These objects as well as other objects of this invention will become readily apparent after reading the following description of the accompanying drawing in which:

FIG. 1 is a perspective of a shallow depth load center constructed in accordance with teachings of the instant invention.

FIG. 2 is an exploded perspective of the load center of FIG. 1, with its cover and front plate separated from the enclosure.

FIG. 3 is a front elevation of the load center with the cover removed.

FIG. 4 is an enlarged front elevation, with portions cut away, illustrating the mounting of circuit breakers in the load center.

FIG. 5 is a cross section taken through line 5-5 of FIG. 4, looking in the direction of arrows 5-5.

FIG. 6 is a cross section taken through lines 6-6 of FIG. 3, looking in the direction of arrows 6-6.

FIG. 7 is a fragmentary cross section taken through line 7-7 of FIG. 4, looking in the direction of arrows 7-7.

FIG. 8 is an exploded perspective showing the main elements of the load center of FIG. 1.

Now referring to the FIGS. load center 10 of FIG. 1 includes a panelboard comprising shallow, rectangular enclosure 11 having removable front cover 12 secured in place by a plurality of sheet metal screws 13. The latter extend through clearance holes 14 in front wall 12 and are received by threaded apertures 15 along the in-turned marginal edge of enclosure 11.

Wall 12 is provided with rectangular cutouts 16, 17 and rectangular partitions 18, 19 extending rearwardly from the boundary edges defining cutouts 16, 17 respectively. Partitions 18, 19 extend to enclosure rear wall 21, with one wall of each of the partitions 18, 19 being provided with double notches 22, 23 to provide clearance for the operation of circuit breaker operating handles 24. The walls with notches 22, 23 and the other walls of partitions 18, 19 are struck from wall 12 during formation of cutouts 16, 17 and the remaining walls of partitions 18, 19 are secured by welds. Openable cover 25 is pivotally mounted to front wall 12 by hinges 26, with spring catch 27 mounted on the rear surface of cover 25 extending through aperture 28 in front wall 12 to maintain cover 25 in close position wherein it closes the recesses defined by rectangular partitions 18, 19.

The panelboard interior comprises insulating sheet 31 positioned adjacent to the front surface of enclosure rear wall 21. Sheet 31 is appropriately notched to provide clearances for two circuit breaker mounting brackets 32 and two pairs of insulator block retainer elements 33, 34. Brackets 32 and elements 33, 34 extend forwardly from enclosure rear wall 21, being welded thereto.

As best seen in FIG. 7, element 33 is of generally L-shaped cross section, with the free end thereof hooking over ledge 35 of insulator block 40. The free edge of element 34 flares away from element 33, to provide a camming surface 36 which facilitates pivoting of insulator 40 about element 33 to a point where shoulder 37 falls beneath retaining ear 38 struck from element 34. When shoulder 37 moves to the rear of gear 38, element 34 springs back toward element 33 locking insulator 40 in its operative position abutting insulating sheet 31. In a similar manner, the other pair of elements 33, 34 secure the other insulator block 50 in its operative position.

A pair of threaded inserts 41 at the front surface of block 40 receive screws 42 after they have passed through lock washers 43, clearance apertures 44 in conducting straps 45, and clearance apertures 46 in insulating sheet 47, the latter lying adjacent to the front surface of block 40. Similarly, another pair of screws 42 and lock washers 43 secure conducting strap 55 and another insulating sheet 47 to block 50.

It is noted that conducting straps 45 and 55 are identical. In particular, strap 55 includes main portion 61 having offset portion 62 at one end thereof and ear 63 at the other end thereof. Wire grip 64 is mounted to ear 63. Similarly, strap 45 includes main portion 51, offset portion 52 at one end thereof and ear 53 with wire grip 54 mounted thereto at the other end of main portion 51.

Offset portions 52, 62 extend beyond both edges of the respective main portions 51, 61. These transverse extensions of offset portions 52, 62 each terminate in a pair of stabs 65, 65, with each stab 65 being adapted for frictional engagement by the line terminal of a so-called plug-in type circuit breaker 70, eight of which form part of load center 10. The stab projections extending in one direction pass through slots in insulating sheets 66, while the other stab projections extend through slots in another insulating sheet 67. Insulating sheets 66 and 67 are positioned adjacent to opposite edges of main strap portions 51, 61, and are retained in operative positions by brackets 32. Four screws 68 extend through clearance aperture 69, in insulating sheet 71, and are received by threaded apertures in ears 72 at the forward end of each bracket 32, to secure insulating sheet 71 in operative position adjacent to the inner surface of front wall 12.

Each of the brackets 32 is of similar construction, the essential difference being that one type is a mirror image of the other type. Each bracket 32 is provided with two circuit breaker mounting hooks 73, 73 which fit into cooperating mounting recesses 74 at the load end of circuit breakers 70, and provide pivots about which circuit breakers 70 are rocked into operative position with their line terminals 75 frictionally engaged with stabs 65. Terminal 75 is at the end of breaker 70 opposite recess 74 and at the bottom thereof. As is well known to the art, circuit breaker load terminal 77 is positioned at the load end of breaker 70, above mounting recess 74.

It is noted that breaker 70 is of a type used for residence and light industrial applications, with the thickness T thereof being considerably less than the width W and overall height H, the latter including the housing height as well as room required to operate handle 24.

Thus, it is seen that the depth of enclosure 11 is controlled by the thickness of two circuit breakers stacked side by side. Naturally, if only a single line or layer of circuit breakers is to be utilized, then the depth of the panelboard enclosure is reduced by the thickness of a line of circuit breakers. It is noted that the circuit breakers illustrated in the drawings and hereinbefore described are constructed to be 1 inch thick. However, compatible breakers in twin form may be utilized to provide two, rather than one, pole unit per inch of thickness.

It is also noted that in the following claims the uses of "top" and "bottom" with reference to the circuit breaker are merely relative terms, and may change depending upon the orientation or absolute position of the circuit breaker as it is mounted in the load center.

Although there have been described preferred embodiments of this novel invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, this invention is to be limited not by the specific disclosure herein, but only by the appending claims.

Claims

1. A loadcenter comprising a plurality of circuit breakers and a panelboard mounting said circuit breakers; each of said circuit breakers including a relatively flat rectangular case with line and load terminals at opposite ends thereof and a contact operating handle projecting through an aperture in a narrow top wall of said case which extends between sidewalls of the case that are many times larger in area than the area of the top wall; said panelboard including a shallow rectangular housing comprising a rear wall and a front wall closely spaced with respect to said rear wall; line busing means mounted within said housing and insulated therefrom; mounting means within said housing; said mounting means operatively positioning said plurality of circuit breakers within said housing with said sidewalls disposed in planes extending generally parallel to said rear wall; said operating handles disposed behind said front wall and said line terminals electrically connected to said line busing means; said front wall having opening means through which said operating handles are engageable for

2. A loadcenter as set forth in claim 1, in which a first and a second of said circuit breakers are positioned with their bottom walls in confronting relationship and the handles thereof projecting in opposite

3. A loadcenter as set forth in claim 1, in which a first and a second of said circuit breakers are positioned with the line terminal end walls

4. A loadcenter as set forth in claim 1, in which the mounting means includes hook portions about which the circuit breakers are pivoted in

5. A loadcenter as set forth in claim 4, in which the busing means includes generally planar portions constituting stabs; said line terminals of said circuit breakers being frictionally engaged with said stabs; said planar

6. A loadcenter as set forth in claim 5, in which said busing includes first and second identical conducting straps, each having a main portion and an offset portion at the end of said main portion; said offset

7. A loadcenter as set forth in claim 6, in which said main portions are aligned with each other and disposed in a common plane, said offset

8. A loadcenter as set forth in claim 7, in which said offset portions are in alignment, a wire grip means mounted to each of said main portions at

9. A loadcenter as set forth in claim 7, in which each of said offset portions provides a sufficient number of said stabs for frictional

10. A loadcenter as set forth in claim 9, in which said offset portions are in alignment and said plane is parallel to said rear wall.