Circuit breaker question

ComfortCreator

Well-Known Member
I realize there is a lot more involved in the question but in general, can or should a circuit breaker get warm when running at near full load?

I have about 1100watts running through a 15amp breaker. I had about 1200 or 1250 and had the breaker go off a few times a day over 3 very warm days. I moved some fans off that circuitnand have just the lights.

I never checked the breaker before as it has never popped since I set it up. Its not blazing hot or too hot to touch, but warm. I want to figure out if I have an issue or not.
 

spek9

Well-Known Member
Yes, they may get slightly warm when subjected to sustained, heavy loads. There is a but here though...

A circuit should only be used for extended periods up to 80% of its capacity. That's called the "80% rule". For a 120V, 15A circuit, 80% is 12A, or 1440W.

Since you are well under that (you stated ~1250W), I wouldn't expect the breaker to heat up to the point of tripping.

Swap out the breaker with an equivalent one from within the panel itself, and see if the problem persists. If not, ditch the bad breaker and replace it with a new one.
 

ComfortCreator

Well-Known Member
Excellent that is good news, hopefully just a replaced breaker. Thanks guys. Can I do it myself or just bring in an electrician?
 

Renfro

Well-Known Member
A breaker should trip at 80% of it's rated amperage.

If the panel is in a hot space (like a garage) then during hot summer months it may trip when it's near 80%. 1440 watts is 80 percent of the 120V 15A feed.
 

Ganjamandan77

Active Member
15A seems small to me, if your running LED and flouro lights maybe be ok. But if your running an HPS light at 400 watts or more i would jump up to a 20A breaker. You also have to know how many amps your equipment draws for that split second when it first turns on. For an example, my home theater amp draws 13 amps when it first turns on, but goes down to almost nothing a split second later. Start up electrical draw should be matched to the breaker.
 

ComfortCreator

Well-Known Member
15A seems small to me, if your running LED and flouro lights maybe be ok. But if your running an HPS light at 400 watts or more i would jump up to a 20A breaker. You also have to know how many amps your equipment draws for that split second when it first turns on. For an example, my home theater amp draws 13 amps when it first turns on, but goes down to almost nothing a split second later. Start up electrical draw should be matched to the breaker.
Thank you. My electrical guy said the same thing, as rhings kick on theres a burst that it needs to handle.

I will update after the visit to report what was done and if it helped.
 

spek9

Well-Known Member
But if your running an HPS light at 400 watts or more i would jump up to a 20A breaker
That's unnecessary. A 400W lamp on a 120V circuit only draws 3.33A. My 1000W HPS draws only 8.33A. Before I went solar with my fans and stuff, I had a 1kW HPS, several fans, an exhaust fan, my controllers and my overhead lighting on a 15A circuit with no issues whatsoever.

Also, if there was a 15A breaker in place, that almost certainly means that the cable run is only 14ga. If you put a 20A breaker on a 15A rated cable, the wire itself becomes the breaker (more like a fuse, actually), meaning good potential for fire.
 

JoeBlow5823

Well-Known Member
That's unnecessary. A 400W lamp on a 120V circuit only draws 3.33A. My 1000W HPS draws only 8.33A. Before I went solar with my fans and stuff, I had a 1kW HPS, several fans, an exhaust fan, my controllers and my overhead lighting on a 15A circuit with no issues whatsoever.

Also, if there was a 15A breaker in place, that almost certainly means that the cable run is only 14ga. If you put a 20A breaker on a 15A rated cable, the wire itself becomes the breaker (more like a fuse, actually), meaning good potential for fire.
Yeah i dont know if he was suggesting to swap the 15 for a 20 but if he was he is a real moron. You are asking for a fire doing that. Never just swap out a bigger breaker for a smaller one because its tripping unless you know for a fact that all the wire on that circuit can handle the larger load which is usually pretty hard to know unless you can see through walls.
 
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spek9

Well-Known Member
Yeah i dont know if he was suggesting to swap the 15 for a 20 but if he was he is a real moron. You are asking for a fire doing that. Never just swap out a bigger breaker for a smaller on because its tripping unless you know for a fact that all the wire on that circuit can handle the larger load which is usually pretty hard to know unless you can see through walls.
It's not a good idea to give electrical advice without clearly noting important details, such as a warning that when upsizing a breaker, the wiring has to be swapped out as well. I'd advise swapping the receptacles too, just so at a glance, it's easy to see that it's a 20A circuit (plus it allows you to actually use things that require between 15-20A).

Fires and electrocutions can occur when electrical work goes wrong. To boot, if electrical is done incorrectly, insurance companies rarely pay out if a fire does start, or someone does get injured or killed.
 

Nizza

Well-Known Member
I would try to split the load to two breakers if possible. Maybe an extension cord from a different room just to take some of the load off like the extraction fan/ circulation fans
 

JoeBlow5823

Well-Known Member
I would try to split the load to two breakers if possible. Maybe an extension cord from a different room just to take some of the load off like the extraction fan/ circulation fans
Thats the ideal way to do it. Ballast only on one circuit. Everything else on another.
 

Ganjamandan77

Active Member
Yeah i dont know if he was suggesting to swap the 15 for a 20 but if he was he is a real moron. You are asking for a fire doing that. Never just swap out a bigger breaker for a smaller one because its tripping unless you know for a fact that all the wire on that circuit can handle the larger load which is usually pretty hard to know unless you can see through walls.
No shit the wire has to match the breaker. When i go into new homes to wire them for audio i never see anything smaller than 12-2 or 12-3 romax which will handle a 20A breaker.
 

spek9

Well-Known Member
No shit the wire has to match the breaker. When i go into new homes to wire them for audio i never see anything smaller than 12-2 or 12-3 romax which will handle a 20A breaker.
You should have clearly and explicitly stated something about wire size then.

Just because you think you've never seen anything smaller as far as mains electrical wire gauge as you're running audio cable, doesn't mean anything. 12ga wire is not used on known 15A circuits normally at all. It is absolutely not the norm, so assuming it is and providing no warning is quite dangerous.

Also, it's Romex ;)
 
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