I was called out to a home today for a possible problem with the air conditioning unit. the upstairs unit has only #10 run to it but it calls for 48.5 amps circuit ampacity. put my clamp on amp meter on it and it was pulling 41 amps. checked the outside panel and 240 volt breaker and it was a 2 pole 30 amp breaker. shouldn't the breaker be tripping with it pulling 40 amps on the circuit.and is there anything else wrong with this.
shouldn't the breaker trip
- Thread starter drwill
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- Lockport, IL
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- Semi-Retired Electrical Engineer
Re: shouldn't the breaker trip
The more of an overload you impose on a breaker, the faster it will trip. But a small overload might continue forever, without tripping the breaker. I don't have a breaker time-current curves with me. But I would not be surprised if someone who had such a curve looked it up and told us that a 30 amp breaker could sustain a 50 amp load, without ever tripping.
The more of an overload you impose on a breaker, the faster it will trip. But a small overload might continue forever, without tripping the breaker. I don't have a breaker time-current curves with me. But I would not be surprised if someone who had such a curve looked it up and told us that a 30 amp breaker could sustain a 50 amp load, without ever tripping.
ron
Senior Member
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- New York, 40.7514,-73.9925
Re: shouldn't the breaker trip
Using the link below as an example
http://www.geindustrial.com/solutions/engineers/docs/GES-9888.pdf
A continuous 150% overload would take approximately 400 seconds (considering manufacturers tolerances) to trip the breaker.
Using the link below as an example
http://www.geindustrial.com/solutions/engineers/docs/GES-9888.pdf
A continuous 150% overload would take approximately 400 seconds (considering manufacturers tolerances) to trip the breaker.
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