20A Homeline Breaker tripping with compressor

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donselec

donselec

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Location
Aurora, CO, USA
Has anyone ever had a problem with Square D Homeline breakers (from Home Depot) tripping when someone runs a compressor. Can't say for sure what size comp it is but it should run on a 20A 120V circuit. I had a g.c. change it to a 30A because his comp was always tripping it, now I have a h.o. who is tripping his with his compressor. It's an HACR breaker. Are they too sensitive or what. Wondered if anyone else had it.
Thanks.
 
It's probably not the breaker. Compressors like all motors have high inrush currents, especially because the compressor may be fighting against the air pressure in the tank. If it's too much, you have a tripped breaker on your hands.
 
Compressors are the #1 thing around homes that trip breakers. Particularly these cheap-o's that go on sale at the home centers. I don't think it's your breakers. The guts of the HOM breakers are identical to the QO's.
 
i would amprobe the wire to see what the current is when the compressor starts up and runs. dont put in a bigger breaker since you are going against the NEC by putting a 30A breaker on 12awg conductors
 
If the compressor has a unloader to allow it to start unloaded, it may not be working. Also something may be wrong in the motor, capacitor or start switch.
 
electricman2 said:
If the compressor has a unloader to allow it to start unloaded, it may not be working. Also something may be wrong in the motor, capacitor or start switch.
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Or the owner is running a tablesaw at the same time... ;) :grin:
 
electricman2 said:
If the compressor has a unloader to allow it to start unloaded, it may not be working. Also something may be wrong in the motor, capacitor or start switch.
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The three things I find wrong normally are, stuck closed compressor head unloader valve, bad/leaky tank check valve, and tight compressor pistons/vanes. The cheap compressors are just tight.
 
Sounds good guys, I just wanted to see if there was anything inheritantly wrong with Homeline breakers, it doesn't sound like it. Also with the cold weather we've had that could cause a problem too.
 
electrical person. you are absolutley not going against code by using a 30 amp breaker on a motor circuit. the exception to the 15,20,30 amp rules for wire include motor circuits and hvac for 2 or the exceptions. there are others as well .see 240.4 G the most important thing in this application is to see what hp we are talking about. if hp is not shown then at least you can use the nameplate to determine what size breaker to use. if you have for instance a 1 hp 115 volt single phase motor the tables show 16 amps which would allow you to use # 12 wire. 1.25 x 16 = 20 amps. you take the 16 amp nameplate current and use table 430.52 which allows a maximum of 250 % of the nameplate for a standard inverse time breaker which is 40 amps. Remember the code wants us to get the motor started so thats why the exception to the rule.
 
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Haha okay Peter it was only a joke I am sorry if you didn't take it that way:roll: . I know it doesn't matter what brand of breaker you have well unless its an old FPE that might be the only exception lol
 
stew said:
electrical person. you are absolutley not going against code by using a 30 amp breaker on a motor circuit. the exception to the 15,20,30 amp rules for wire include motor circuits and hvac for 2 or the exceptions. there are others as well .see 240.4 G the most important thing in this application is to see what hp we are talking about. if hp is not shown then at least you can use the nameplate to determine what size breaker to use. if you have for instance a 1 hp 115 volt single phase motor the tables show 16 amps which would allow you to use # 12 wire. 1.25 x 16 = 20 amps. you take the 16 amp nameplate current and use table 430.52 which allows a maximum of 250 % of the nameplate for a standard inverse time breaker which is 40 amps. Remember the code wants us to get the motor started so thats why the exception to the rule.
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Well this feeds a GFI convenience outlet in a garage which could be used for other things, so that rule might not apply. It also feeds 2 other outside outlets. I suppose the compressor would have to be hardwired on a dedicated circuit for that. Might be an option if he continues to have problems.
 
stew said:
electrical person. you are absolutely not going against code by using a 30 amp breaker on a motor circuit.
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Besides the fact this circuit supplies a general purpose receptacle circuit we also can not supply equipment equipped with 20 amp plug with a 30 amp circuit.

Unless this compressor is labeled for a 30 amp circuit we can not use a 30 amp circuit.
 
i guess i didnt see the fact that there was other receps. but the code does allow multiple loads to be taken from a circuit that includes a motor. If this is simply a garage then I would think the multiple load would apply would it not? I also dont understand your logic about this having to be labeled 30 amps. The motor quite probably is labeled less than that but may require 30 amps to start.
 
peter d said:
True, the only difference is that HOM's do not contain the "visi trip." Otherwise they perform the same.
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Square D QO and HOM breakers in the 15A and 20A single pole versions have a "Qwik-Open" mechanism that effectively cause them to trip at about 6X FLA (maybe even less), therefore a motor load approaching the rating of the breaker may trip on start-up.

Square D makes a slow trip version of the QO. Their HID breakers also do not have the quick trip characteristic.

Myth buster fact: HACR ratings do not guarantee that a breaker can handle motor startup currents
 
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