Breakers after faults

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Ken9876

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What should be done with a breaker that has seen several good faults, one good enough to blow the overloads out of the overload relay and weld the starter contacts closed? Is there a standard on this, my feeling is to replace it.
 
Ken9876 said:
What should be done with a breaker that has seen several good faults, one good enough to blow the overloads out of the overload relay and weld the starter contacts closed? Is there a standard on this, my feeling is to replace it.
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Go with your feelings.
 
Ken9876 said:
20 amp 3 pole MCP 600v, not very large, direct replacement for westinghouse made by eaton, about $400
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I guess you'll have to wait for one of the NETA guys to chime in, but that one is real borderline, in my opinion. Not a good candidate for rebuilding, and not small enough to replace "just because". I'd really like to know what the NETA guys use as their guideline on breakers that have taken one or several bolted faults.
 
BackInTheHabit said:
Got a picture of a $5000.00 breaker?
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ive seen 10,000 dollar breakers before. we have one at the shop

its a rather large breaker that fits into switch gear, pretty sure it was 800 amp 480 volt 3 phase. im thinking it was a GE. the boss said it was 10k dollars. might be an older model thats hard to get
 
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Pass rated current through breaker, measure voltage drop across closed contacts, < 30 mV =~ good.
 
The breaker should be inspected and tested by someone qualified in determining the condition of the CB, if in doubt replace. Small frame substantial fault replace it.


Posted previously closed after a fault resulted in an electrician taking a trip in an ambulance.

Scan of an old pic...

CircuitBreakers.jpg
 
BackInTheHabit said:
Got a picture of a $5000.00 breaker?
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The life safety selective coordination requirements in 700.27 are making manufacturers install circuit breakers with electronic trip units which cost way over 5Gs even for 250A frame breakers - such as SquareD Powerpact with Powerlogic breakers. Very sophisticated equipment. Anyone had to buy some of those?
 
brian john said:
The breaker should be inspected and tested by someone qualified in determining the condition of the CB, if in doubt replace. Small frame substantial fault replace it.
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I understand Marc's concern about cost, and I agree with him on larger cost breakers that can be repaired.

But Brian's post may come closer to the mark for the OP's situation.
First though, I would like to know the reason for the original fault, and hopefully be able to clear it before installing a new or reconditioned CBer.


I did a job years ago where we were going to replace what seemed like a somewhat normal CBer. The CBer was around $12,000 to replace. I was able to send it out and have it rebuilt for around $3500. It was a Westinghouse - 500A CBer.
 
Pierre C Belarge said:
The CBer was around $12,000 to replace. I was able to send it out and have it rebuilt for around $3500. It was a Westinghouse - 500A CBer.
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That's interesting, because my rule of thumb when guesstimating rebuild costs is 1/3 new price. Your sentence there pretty much confirms what I've been observing over the years. Granted, we're talking about breakers that are in the thousands of dollars and more. I know some of the smaller one's are technically rebuildable, but it doesn't make much sense to rebuild a E frame breaker, for instance.
 
I have tested and installed CB's that individually cost 28,000.00 plus. Had to buy a SWBD with 2 of the same type CB's copper bus and paid 26,000.00 for it.

1 circuit breaker 28,000.00 = 2 circuit breakers and switchboard $26,000.00...

SAME model style and options.
 
brian john said:
1 circuit breaker 28,000.00 = 2 circuit breakers and switchboard $26,000.00...
SAME model style and options.
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MCC buckets and complete sections have been that way for years. If you are buying an single breaker or MCC bucket, you really don't have a choice of the brand so you are locked in. If you are buying the switchgear and the breakers or the MCC section with the starters they have to be more competive as you could use other brands...you are not locked in. I have purchased complete sections with buckets many time when I only needed the buckets. The sections would be scraped after we removed the buckets.
 
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