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The Elusive Delta Circuit Breaker #152376 12/18/04 09:41 PM
Joined: Dec 2000
Posts: 4,281
electure Offline OP
Member
Quote
I bought this on eBay. I had seen them in old catalogs, but never laid eyes
on one. Use prohibited by NEC section 384-16 (e)beginning with the 1978 edition.
The date on the box is May 27 1963, so it's almost as old as I am.


NORCAL


[Linked Image]


[Linked Image]


[Linked Image]


(edited to post clearer images)



[This message has been edited by electure (edited 01-08-2005).]

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Re: The Elusive Delta Circuit Breaker #152377 12/19/04 02:30 PM
Joined: Apr 2002
Posts: 2,527
B
Bjarney Offline
Moderator
 
The reason they were no longer permitted in Article 384 went something like this — They were used to provide one 3ø circuit in a 1ø 3w panelboard. The 1ø panelboard could serve a 3ø load such as a package air conditioner in a retail store where everything else on the feeder/service entrance was 1ø.

They were shot down as a potential shock hazard—where the 1ø panelboard disconnect was opened, there could be backfeed through the highleg in the ‘outboard’/'delta' 3ø circuit through the served 3ø load.

Norcal’s pictured ‘4-space/3-pole’ breaker has 4 cable connections (lugs) and two bus clips to connect to two (1ø) ‘hot’ busses in the panelboard. The sole highleg breaker pole had ‘in and out’ cable lugs. It was a strangely fitting compliment to 4-wire delta electric service with an ‘outboard’ transformer for 240/120 4-wire (in some cases open-)delta systems.




[This message has been edited by Bjarney (edited 12-19-2004).]

Re: The Elusive Delta Circuit Breaker #152378 12/20/04 09:24 PM
Joined: Sep 2004
Posts: 167
S
sandsnow Offline
Member
Wow even though there was a potential shock hazard, it was still marked "safetybreaker" on the box!!

Very educational


Larry LeVoir
Inspector
City of Irvine, CA
Re: The Elusive Delta Circuit Breaker #152379 12/21/04 08:41 AM
Joined: Sep 2002
Posts: 885
N
NORCAL Offline
Member
What is called the Cutler-Hammer "Classic" now had "Safetybreaker" on the package for many years.

Re: The Elusive Delta Circuit Breaker #152380 01/09/05 12:17 AM
Joined: Sep 2002
Posts: 885
N
NORCAL Offline
Member
Scott,thank you for replaceing the photos the detail is much clearer.


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