# How many amps does it take to trip a 60 amp breaker



## Shockdoc (Mar 4, 2010)

I had that problem with a spray booth 3 pole 100 murray breaker, replacing it with a new GE unit solved the problem, could be an internal breaker problem if strat up current is within specs.


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## Big John (May 23, 2010)

Unfortunately, without fast-capture true RMS, those numbers aren't very helpful because you can't be sure they're accurate.

But for a motor with 2.2FLA, a even locked rotor current of 60A sounds awfully darn high. Is there a compressor in this thing?

-John


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## Podagrower (Mar 16, 2008)

Big John said:


> Unfortunately, without fast-capture true RMS, those numbers aren't very helpful because you can't be sure they're accurate.
> 
> But for a motor with 2.2FLA, a even locked rotor current of 60A sounds awfully darn high. Is there a compressor in this thing?
> 
> -John


No compressor, just a standard (for our area) heat pump setup.


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## mbednarik (Oct 10, 2011)

are there hot breakers on both sides of this breaker? Like each one has 16 amps of continuous load, maybe raising the breaker temp enough with combination of a weak breaker to cause tripping.


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## sstlouis03 (Jun 23, 2011)

Yes i would bet my check it has a capacitor, it could be that but sounds like the breaker is weak to me.


Sorry didn't see that you had replaced the breaker.


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## Peerless Design (Dec 3, 2011)

That depends on the amount of current. The magnetic protection of a thermal magnetic breaker will trip very rapidly with very high current as in a fault condition, but the thermal protection will trip very slowly with a slight overload. Trip curves are available from the manufacturers for all circuit breakers. These can usually be found online.

If the running load is 2.2 amperes, there is no way the load would ever be high enough to trip a properly functioning 60 ampere breaker. It sounds like the breaker is oversized and defective.


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## new shocker (Feb 4, 2012)

A heat pump is an a/c unit with 4 way reversing valve and a capacitor...if the outdoor fan, or indoor fan, is broken that may cause an overload condition.


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## Podagrower (Mar 16, 2008)

The breaker that i took out was a 60 amp, bottom of the panel, so only 1 breaker next to it with a small, non constant load. It's a 60 because the ahu has 10 kw of backup heat. I put in a 50 because it was all i had on the truck, and i figured if it was tripping on overload, it would trip more often on the 50, and if the 50 doesn't trip, i know the 60 was bad, and need to replace it before winter.


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## brian john (Mar 11, 2007)

Rough rule of thumb for residential thermal magnetic circuit breaker on instantaneous operation, 4-10 times the name plate rating 60 amp CB 240 amps-600 amp.

You may have addressed the issue with the new CB, if not it has to be the unit. ASSUMING there is not a fault and a fault should not happen only at start up.

You should have a Min/Max meter and it should be true RMS.

This is the new millennium, this ain't 1984.


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## Big John (May 23, 2010)

Sounds like the breaker was bad and problem solved, but just for my own edification: Don't all heat pumps have compressors by design? I've never seen one without and don't know how that would work.

-John


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## Bbsound (Dec 16, 2011)

So you did not check the load with the heat coils on? You could have a broken heater coil that is grounded. Heat comes on breaker trips.


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## Podagrower (Mar 16, 2008)

Big John said:


> Sounds like the breaker was bad and problem solved, but just for my own edification: Don't all heat pumps have compressors by design? I've never seen one without and don't know how that would work.
> 
> -John


Yes, all heat pumps have compressors, but this is the breaker feeding the Air Handler inside, the compressor outside is fed from a different circuit.



Bbsound said:


> So you did not check the load with the heat coils on? You could have a broken heater coil that is grounded. Heat comes on breaker trips.


I have not opened the AHU yet, taking the customer's word that the AC guys have checked it out, and it is fine. The heat strips probably haven't kicked on in 3 months (Florida). But I think I'm going to have to to check for motor bind or a bad capacitor causing extremely high current at start up.


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## Podagrower (Mar 16, 2008)

brian john said:


> Rough rule of thumb for residential thermal magnetic circuit breaker on instantaneous operation, 4-10 times the name plate rating 60 amp CB 240 amps-600 amp.
> 
> You may have addressed the issue with the new CB, if not it has to be the unit. ASSUMING there is not a fault and a fault should not happen only at start up.
> 
> ...


And yes, I need to invest in some better test equipment. My best meter is in an attic about an hour from home, and I've been waiting for the GC to get the job ready for me to finish. I've looked at a variety of meters, but there are almost too many out there to pick from.


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## Stab&Shoot (Aug 23, 2011)

mbednarik said:


> are there hot breakers on both sides of this breaker? Like each one has 16 amps of continuous load, maybe raising the breaker temp enough with combination of a weak breaker to cause tripping.


I agree


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