breakers vs. fuses
breakers vs. fuses
(OP)
Is there a situation where ok to use a breaker in place of a fuse? For example, the 3 legs of power coming into a 3-phase pumping unit. I'm unable to find anything mentioning this substitution.
What about using a breaker on the leg of a small transformer, I couldn't see the harm, but have never seen such a thing, and don't have a real good answer as to why not to, other than 'it will look funny'.
Aside from codes, local or otherwise, Is it as simple as trip/interrupt rating matching?
What about using a breaker on the leg of a small transformer, I couldn't see the harm, but have never seen such a thing, and don't have a real good answer as to why not to, other than 'it will look funny'.
Aside from codes, local or otherwise, Is it as simple as trip/interrupt rating matching?






RE: breakers vs. fuses
If you are asking, if you can mix and match fuses and breaker for in a single overcurrent device of a multiwire circuit, the answer is No. If a circuit breaker is used it is required to open 'all' ungrounded conductors of the circuit simultaneously, both manually and automatically (NEC 240.15 in the USA).
Rafiq Bulsara
http://www.srengineersct.com
RE: breakers vs. fuses
Otherwise, I agree with Rafiq.
David Castor
www.cvoes.com
RE: breakers vs. fuses
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RE: breakers vs. fuses
RE: breakers vs. fuses
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If we learn from our mistakes I'm getting a great education!
RE: breakers vs. fuses
RE: breakers vs. fuses
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If we learn from our mistakes I'm getting a great education!
RE: breakers vs. fuses
ABB K-line - fused= KDON
GE AK series - fused= AKU or AKRU
Just a couple examples, not needed as much anymore due to higher AIC's on more modern breakers as ScottyUK mentioned.
RE: breakers vs. fuses
RE: breakers vs. fuses
And yes ScottyUK, I am also an old timer, at least in experience.
RE: breakers vs. fuses
I don't think there was much uptake of breakers at high fault levels in the UK until the breakers became capable of breaking the faults directly. There are a few examples but not many that I can think of. Even now there is a bias toward fuses in many of the old industries like steel and power.
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If we learn from our mistakes I'm getting a great education!
RE: breakers vs. fuses
One big issue I see with fuses used alone is that for fault currents not in the current-limiting range, they may be very slow to respond, sometimes resulting in quite high arc-flash levels.
Alan
"The engineer's first problem in any design situation is to discover what the problem really is." Unk.