AU673534B2

AU673534B2 - Circuit breaker enclosure

Info

Publication number: AU673534B2
Application number: AU46829/93A
Authority: AU
Inventors: Keith Wray Ball; Kenneth Neill
Original assignee: Square D Co
Current assignee: Schneider Electric USA Inc
Priority date: 1992-07-17
Filing date: 1993-07-19
Publication date: 1996-11-14
Anticipated expiration: 2013-07-19
Also published as: WO1994002979A1; GB9215302D0; IE72151B1; AU4682993A; JPH06511137A; GB2268831B; GB2268831A; IE930500A1

Description

OPI DATE 14/02/94 AOJP DATE 12/05/94 APPLN. 10 46829/9 Jlll 111111 1111111111111 1Jl PCT NUMBER PCT/US93/06749 ~II l lIIl~IHllI]11111 It1111 A0346829 INTERNATIONAL AP1LUCATION PUBLISHIED UNDERr it', PAT[NTC)OPMA [X ON TRIAY (PCT Intrnaioal atnt iasifvaton~ :Al (11) International Publication Number: WO. 94/02979~ I 02B /54(43) International publication Dale: F Icbru ir 1994 (0'.02,94) (21) International Application Number: P'CT US93 06-4914 (81) Designated States: At JI1. I (22) International Filing Date: 19 JuI 199,193 t01(9.1) P'ublished If it intetrn:ational vvarh report iPriorit data: IT July 1992 (0'V92) (7)Aplican t fo~r all idetignated Stime eicept LSo: SQUAR k) COSPANY [US US); 1415 South Roselle Road. Pala-i tine. I L 60067 (US) (72) Inventors; and inventors/Applicant (fior CS oink). NEILL, Kenneth (M)i CIB); 7 13edw~n Close. Swindon. Wiltshire (Gift. BALL, Ket.Wray IGB (iGB]. 168 Whitworth Road, Swindon.

Wiltshire (64I (54)Tltle: CIRCUIT BREAKER ENCLOSURE e (57) Abstract A vented enclosure (101) is provided ror moulded case circuit breakers and includes a venting arrangement to permit release of internal pres.

sure caused in use by short circuit fault conditions. The venting arrangement is provided in the form of louvers (14) formed in the enclosure, or a blow-out panel (15) or anfap (16) mounted over an aperture formed in the enclosure, with the panel (I5) or flap (16) being formed of synthetic plastic material.

I

C P I F1 1 '4-1l71JCI("-I: I f -1- CIRCUIT BREAKER ENCLOSURE The invention relates to circuit breakers and more particularly to moulded case circuit breakers enclosures therefor and to an I-line panelboard for mounting such circuit breaker enclosures.

With M.C.C.B.'s fitted with enclosures problems can occur when such breakers open under short circuit conditions since gas and particles are generated under such conditions. This can cause problems with damage to the M.C.C.B. enclosure by pressure build up and furthermore the generated particles can impair the dielectric withstand of the electrical circuits throughout the panelboard assembly.

It is an object of the present invention to obviate or mitigate one or more of the above disadvantages.

According to one aspect of the present invention there is provided a secondary mou\ded c-se.

enclosure housing a circuit breaker therein thereby segregating the circuit breaker from other circuit breakers, said enclosure being formed with a venting arrangement to allow release of internal pressure caused by short circuit fault conditions, wherein said venting 20 arrangement includes an aperture, disposed in said enclosure; and a blow out panel secured at its edge over the entire aperture to thereby cover the aperture, but adapted to be blown open under high pressure conditions, to uncover said aperture thereby releasing the pressure out of said enclosure.

S

According to another aspect of the present invention there is provided an assembly Aou\AeA c-ase including a circuit breaker and a secondary enclosure enclosing the circuit breaker therein thereby segregating the circuit breaker from other circuit breakers, said enclosure including electrical connections for coupling wire conductors to the circuit breaker, 0 a venting arrangement, disposed in said enclosure, disposed in said enclosure, for v r ^zro A 11U' 1 1I~f 41y" i.ICII VI~ d I releasing internal pressure caused when the circuit breaker interrupts under a short circuit fault condition, said arrangement includling an aperture formed in said enclosure; and a blow-out panel secured at its edges over the entire aperture to thereby cover the aperture, but adapted to be blown open under high pressure conditions, to uncover said aperture, thereby releasing the high pressure out of said enclosure; and a set of barriers adapted for surrounding the electrical connections from particles generated when the circuit breaker interrupts due to the short circuit condition.

Preferably the blow-out panel is secured at all of its edges over the aperture formed in the enclosure. The panel may be formed of synthetic plastics material. Insulating barriers may be provided to prevent vented exhaust particles from coming Into contact with electrical connections. Preferably the insulating barriers are located around the connections.

15 Preferred embodiments of the invention will hereinafter be described with reference to the accompanying drawings.

The foregoing and further features of the invention may be more readily understood 20from the following description of preferred embodiments thereof, by way of example, with reference to the accompanying drawings, in which:- Fig. I is a perspective view of the front of an 1Wine panelboard; Fig. 2 is a side elevational view of a portion of the panelboard of Fig. 1 showing a centre cover located thereon; WO 94/102979 PCT/US93/06749 3 Figs. 3a and 3b are view, on enlarged scale, of the circled portion A of Fig. 2 showing alternative fixings for the centre cover; Fig. 4 is a side elevational view of an M.C.C.B.

enclosure plug-in unit inserted into the stack of the panelboard; Fig. 5 is an end elevational view of the end of the unit of Fig. 4 remote from the stack; Fig. 6 is an end elevational view of the other end of the unit of Fig. 4 adjacent to the stack; Fig. 7 is an end elevational view of an alternative arrangement to Fig. 6; Fig. 8 is a side elevational view of an alternative M.C.C.B. enclosure plug-in unit, and Fig. 9 is an end elevational view in the direction of arrow B on Fig. 8.

Referring now firstly to Fig. 1 there is shown an I-line panelboard assembly 10 with two vertical stacks of plug-in enclosed M.C.C.B.'s 11 shown located in their plugged-in positions. Each of the M.C.C.B.'s enclosures 11 is vented into a central vertical expansion chamber 12 an a cover 13 of synthetic plastics material is located at the lower end for protecting a bus stack (not shown) located therebelow. The M.C.C.B.'s enclosures 11 may be vented in a plurality of forms with enclosure lla being formed with a vent opening 14, enclosure llb having a panel 15 which is secured at its edges to form a "blow-out" panel and enclosure llc having a flap 16 which is rigidly secured at one edge and which may be perforated, both the panel 15 and the flap 16 being formed of synthetic plastics material. The detail of such venting will be described in more detail hereinafter. Customer cabling compartments are located vertically at each side of the assembly WO 94/02979 PCT/US93/06749 4 beneath panels 17. A central cover 18 (Fig. 2) is located over the expansion chamber 12 in the position indicated by arrow 18A, Referring now to Fig. 2 there is shown the panelboard bus stack 19, the central cover 18 which is located over the expansion chamber 12 and a stack barrier 20 located between stack 19 and cover 18.

Fig. 3a shows, on enlarged scale, the circled portion A in Fig. 2 dnd shows the detail of an assembly 21 comprising a nut and bolt fixing with a pre-loaded spring to enable release movement of cover 18 should there be excessive pressure build-up within chamber 12. Fig. 3b shows a similar view to Fig. 3a but with a fixed nut and bolt assembly 22.

Referring now to Figs. 4 and 5 there is shown an enclosure 11 which is plugged-in to stack 19. With this enclosure 11 the outer end face is formed with venting louvres 23 which may be provided as an alternative or additional to an aperture 14, panel or flap 16 at the stack engaging end. Cable entry into the enclosure 11 is via holes 24 which are drilled to suit the cable size to be utilized.

Referring now to Fig. 6 there is shown an end elevational view of the enclosure llc of Fig. 1 on enlarged scale. The flap 16 is rigidly located along the base by screws 25 and a slotted perforation 26 provided to enable hingeing or snap-off with pressure build up within enclosure llc. Fig. 7 shows a similar view to Fig. 6 for the enclosure llb, in which panel is located by the edges of screw mounted washers 27 so as to provided a "blow-out" panel with pressure build up within enclosure llb.

Referring now to Figs. 8 and 9 there is shown a further enclosure 11 with details of protection of the electrical connections 28 from contamination from generated particles when the breaker opens under short WO 94/02979 PCT/US93/06749 5 provided at the outer edges of the connections and further barriers 30 are provided between the connections. Furthermore barriers 31 are located over and around the terminal pads 32 of the breaker.

Hence it will be seen that when breakers open under short circuit conditions the arrangements shown provide venting of gas pressure/partic.es to both prevent mechanical damage which could result in the environmental degree of protection being impaired and that particles released to not contaminate the electrical connections.

Claims

1. A secondary enclosure housing aI ircuit breaker therein thereby segregating the circuit breaker from other circuit breakers, said enclosure being formed with a venting arrangement to allow release of internal pressure caused by short circuit fault conditions, wherein said venting arrangement includes an aperture, disposed in said enclosure; and a blow out panel secured at its edge over the entire aperture to thereby cover the aperture, but adapted to be blown open under high pressure conditions, to uncover said aperture thereby releasing the pressure out of said enclosure.

2. An enclosure as claimed in claim 1 wherein the panel is formed of synthetic plastics material.

3. An enclosure as claimed in any preceding claim including insulating barriers 15 adapted to prevent vented exhaust particles from coming into contact with electrical connections, wherein said insulting barriers are located around the connections.

4. An assembly including acircuit breaker and a secondary enclosure enclosing the circuit breaker therein thereby segregating the circuit breaker from other circuit breakers, 20 said enclosure including electrical connections for coupling wire conductors to the circuit a breaker, 0. a venting arrangement, fPp7 h i lure' disposed in said enclosure, for Go.. releasing internal pressure caused when the circuit breaker interrupts under a short circuit fault condition, said arrangement including an aperture formed in said enclosure; and a blow-out panel secured at its edges over the entire aperture to thereby L over the aperture, but adapted to be blown open under high pressure conditions, to uncover said aperture, thereby releasing dithe high pressure out of said enclosure; and a set of barriers adapted for surrounding the electrical connections from particles generated when the circuit breaker interrupts due to the short circuit condition. 7 *l RA 0-- tI-. o 11 ~1wit(HIJ)Y W1E 011~~r -7- An assembly substantially as hiereinbefore described with reference to tha accompanying drawings. DATED this 10th day of September, 191,> j SQUARE D COMPANY By Its Patent Attorneys DAVIES COLLISON CAVE