Bracket assembly for a circuit breaker and an associated method

A plurality of terminal blocks are secured to a molded case circuit breaker by a bracket assembly which includes a mounting bracket placed against a side wall of the circuit breaker molded case. A back-up plate is inserted in a pocket formed between the outer wall and an inner wall of the molded case and electrically isolated from the cavity containing the circuit breaker operating mechanism. Fasteners extend from the mounting bracket through the outer wall and engage the back-up plate. Since the pocket is electrically isolated from the circuit breaker operating mechanism, the back-up plate, and particularly the fasteners, can be made of metal for a solid, durable connection.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a bracket assembly for supporting terminal block 
means on a circuit breaker and a related method for securing the bracket 
assembly to the circuit breaker. 
2. Background Information 
Terminal blocks are mounted on the outside of a circuit breaker and are 
electrically connected to the circuit breaker by wires which are drawn 
through horizontal slots in the circuit breaker housing. Terminal blocks 
are generally connected to auxiliary contact devices such as a bell switch 
which is used to provide an indication of a tripped condition of the 
circuit breaker, or connected to a printed circuit board, for remote 
communications on the functions that the PCB is performing. One 
arrangement for securing the terminal block to the outside of a circuit 
breaker consists of a terminal block which has two T-shaped members on its 
rear wall, each of which fit and slide into a vertical slot on a sidewall 
of the housing. 
Since only two slots are provided on the sidewall of the circuit breaker 
housing, only one terminal block can be used in conjunction such a circuit 
breaker. If additional terminal blocks are required, then additional slots 
need to be provided in the sidewall of the housing, although they would 
unacceptably weaken the housing. For a particular application, it is 
apparent that this arrangement has limitations in that the number of slots 
dictate the number of terminal blocks which can be supported by the 
circuit breaker. 
In order to expand the capacity for supporting a number of terminal blocks, 
a long bracket has been provided in some installations whereby several 
terminal blocks are secured to the bracket. A problem with this type of 
arrangement is that the bracket is unstable or wobbly and cannot be 
fixedly secured to the circuit breaker housing. A further problem with 
this arrangement is that since the bracket is mounted flush against the 
housing, plastic screws are needed to maintain electrical isolation 
between the inside of the housing which contains the circuit breaker 
mechanism and the outside of the housing. However, the walls of the 
housing are generally thin and of poor material for tapping. Thus, plastic 
screws are not a satisfactory solution. Heavy duty double stick tape has 
been suggested, but it also does not adequately secure the bracket to the 
molded housing. 
There remains, therefore, a need for a circuit breaker to accommodate 
several terminal block assemblies alongside its outer housing wall on a 
bracket assembly which is fixedly secured to the circuit breaker housing 
and which is electrically isolated from the circuit breaker mechanism. 
SUMMARY OF THE INVENTION 
The present invention has met the above-described needs. It employs a 
bracket assembly for a circuit breaker for supporting a plurality of 
terminal block assemblies. The bracket assembly comprises a bracket member 
positioned against an outer wall surface of the circuit breaker, a back-up 
plate positioned against an inner wall surface of the circuit breaker in a 
pocket outside of a cavity containing the circuit breaker mechanism, and 
fastening means for securing the bracket member and the back-up plate to 
the wall of the circuit breaker and to each other. The bracket member, the 
back-up plate, and the fastening means may be made of metal, such as 
steel, since no components of the bracket assembly enter into the cavity 
containing the circuit breaker mechanism. The bracket member has a shelf 
portion for supporting the several terminal block assemblies and a leg 
portion which in the exemplary embodiment has an aperture through which 
several leads are drawn for their electrical connection to devices, such 
as an auxiliary switch and/or an alarm, a communications system or a 
remotely located control device. The aperture in the leg portion of the 
bracket member communicates with a slot in the shelf portion for extending 
wires from the circuit breaker mechanism through the bracket assembly for 
their connection to the several terminal block assemblies. 
It is, therefore, an object of the present invention to provide support 
means fixedly and stably secured to the circuit breaker for supporting 
several terminal block assemblies and comprising components which remain 
outside of the cavity containing the circuit breaker mechanism. 
It is a further object of the present invention to provide a bracket 
assembly for supporting a plurality of terminal block assemblies and to 
provide a method for securing the bracket assembly to the circuit breaker 
housing. 
These and other objects of the present invention will be fully understood 
and appreciated from the following description of the invention upon 
reference to the illustrations appended hereto.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring first to FIGS. 1A, 1B, and 2, there is shown in FIGS. 1A and 1B a 
terminal block assembly 10 of the prior art discussed hereinabove which 
consists of T-shaped members 12 and 14 which fit and slide into slots 16 
and 18 in a sidewall 20 of a circuit breaker 22. 
As particularly shown in FIG. 1A, terminal block assembly 10 has three 
compartments 10a, 10b, 10c which are connected by way of wires (not shown) 
soldered to pads (also not shown) permanently mounted in the assembly and 
extending into the circuit breaker, and a screw down clamp (not shown) for 
the user's wires in a manner well known to those skilled in the art. 
Referring to FIGS. 3, 4, 5, and 6 there is shown a bracket assembly 26 of 
the present invention which is mounted to an outer wall or sidewall 28 
(FIG. 3) of a housing for a circuit breaker 24. Circuit breaker 24 is 
similar to circuit breaker 22 of FIGS. 1A, 1B, and 2, and contains a 
circuit breaker mechanism (not shown). 
With particular reference to FIG. 4, bracket assembly 26 comprises a 
bracket member 30, a back-up plate 32, and fastening means, such as screws 
34 and 36 which secure bracket member 30 and back-up plate 32 together in 
sidewall 28. Bracket member 30 has generally an L-shaped configuration 
with a leg portion 30a and a shelf portion 30b. Leg portion 30a has two 
members which are spaced apart and are configured to form an aperture 38 
which communicates with an opening 40 of shelf portion 30b as shown in 
FIG. 6. Shelf portion 30b provides a flat surface and its length, 
preferably, is generally at least half the length of circuit breaker 26. 
Back-up plate 32 is generally flat and rectangular shaped and as shown in 
FIG. 3 has openings which cooperate with openings in the two members of 
leg portion 30a of bracket member 30 to receive screws 34,36 for securing 
bracket assembly 26 to sidewall 28 of circuit breaker 24, more about which 
will be discussed hereinbelow. 
With particular reference to FIG. 3, a base 42 of circuit breaker 24 
cooperates with a cover 44 to form a molded case as is well known in the 
art. With particular reference to FIG. 5, base 42 has an inner wall 46 
spaced inwardly from sidewall 28 to form a pocket 50. Inner wall 46 
separates the pocket 50 from a cavity 48 containing the circuit breaker 
mechanism 51. As shown in FIG. 5, pocket 50 receives plate 32 of bracket 
assembly 26 and is totally electrically isolated from the cavity 48 of 
circuit breaker 24, and therefore, electrically isolated from the circuit 
breaker mechanism 51. 
Pocket 50 is made between sidewall 28 and inner wall 46 along a peripheral 
edge of base 42 as shown in FIG. 5 and is accessed from underneath base 42 
for insertion of plate 32 therein. Also, as shown in FIGS. 3 and 4, 
sidewall 28 has several spaced apart slots 52,54,56, which as mentioned 
hereinabove were used to mount the terminal block assembly 10 of the prior 
art of FIGS. 1A and 1B. 
With reference to FIGS. 4 and 6, when bracket assembly 26 is mounted to 
sidewall 28, aperture 38 of bracket member 30 provides access to slots 
52,54,56, and opening 40 in the shelf portion 30b of bracket member 30 
provides access to aperture 38. These slots 52,54,56 allow leads 53 from 
circuit breaker 24 to be drawn through aperture 38 of bracket assembly 26. 
These wires 53 are electrically connected to one of terminal block 
assemblies 58, 60, and 62 which are supported by shelf portion 30b of 
bracket member 30. The terminal blocks provide connections for leads (not 
shown) connected to an external electrical device, such as an auxiliary 
switch or an alarm, respectively. 
In mounting bracket assembly 26 to base 42, leg portion 30a of bracket 
member 30 is placed against sidewall 28 of base 42, with aperture 38 of 
bracket member 30 framing slots 52, 54, and 56, so as to leave slots 
52,54,56 accessible. Back-up plate 32 is inserted in the pocket 50 between 
inner wall 46 and sidewall 28 of base 42 from underneath, as shown in 
FIGS. 3, 4 and 5, until its holes, one of which is indicated at 32a in 
FIG. 3, are aligned with those in sidewall 28 and with one of the openings 
55 (FIG. 3) in bracket member 30, and screws 34,36 are inserted into the 
aligned holes. The terminal block assemblies 58,60,62 are then mounted to 
shelf portion 30b of bracket member 30, and the wiring 53 from base 42 is 
connected thereto, the leads 53 being brought through slots 52,54,56 in 
sidewall 28 of base 42. From this and as shown in FIG. 5, it is 
appreciated that screws 34,36 remain outside of the cavity 48 containing 
the circuit breaker mechanism 51. In view of this, electrical isolation is 
maintained since back-up plate 32 is located in an electrically isolated 
pocket 50 in the sidewall 28 of the molded base 42 of circuit breaker 24, 
resulting in the bracket assembly 26 being electrically isolated from the 
circuit breaker mechanism 51. Since the bracket assembly 26 is 
electrically isolated, bracket member 30, back-up plate 32 and in 
particular screws 34,36 can be made of a metal, such as steel. 
The manner in which bracket assembly 26 is mounted to base 42 of circuit 
breaker 24 allows a substantially long bracket member 30 for providing a 
mounting surface for several terminal block assemblies 58,60,62 to be 
fixedly secured to base 42 without wobbling. 
Whereas particular embodiments of the present invention have been described 
for purposes of illustration, it will be appreciated by those skilled in 
the art that numerous variations of the details may be made without 
departing from the invention described in the appended claims. 
In accordance with the patent statutes, I explained the principals and 
operation of my invention and have illustrated and described what I 
consider to be the best embodiment thereof.