Very hot breaker

In shop a 15 amp breaker is very hot, it seems to have a 12 gauge wire. It appears to run a few flourescent lights fixtures 5 or so with four bulbs in
each. Shuold the 15 just be changed to 20 or some troubleshooting is in order? req
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reqluq wrote:

How hot is "very hot"? It's normal for a breaker to get a bit warm under load. If it's getting unusually hot, change it with one of the *same* rating.
If you are *sure* the whole circuit is wired with #12, you could go with a 20A breaker, but there's no reason to. Excessive heat indicates a problem with the breaker itself or the connections to it.
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Hot to the knuckle. Not that I have to move my knuckle off of it, but uncomfortable. Connections are solid, I'll go with a new breaker and if that does not work I'll check the load and wire size again and see if a 20 amp will be in order thanks req

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reqluq wrote:

You shouldn't replace it with one of higher rating. That's akin to replacing a fuse with a bigger one. The breaker sizing is based on the circuit and components downstream from the breaker and what they can safely handle.
'Hot' *could* be a simple loose termination. If you're comfortable with the work, open the breaker and check the wire(s) under the screw and see if the screw is properly tightened.
Or the breaker could be defective. If you replace it, use the *same rating* not a larger one.
daestrom
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I'm thinking the wire size was placed there for a specific load and someon put a 15 amp instead of 20 req

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reqluq wrote:

A breaker should not get too hot to hold your finger on even at the maximum rated amperage of the breaker. If the current were too high, the breaker would trip.
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reqluq wrote:

It could be a bad breaker or loose connection. Make sure the screw clamp on the outgoing conductor is tightened properly. Also, try reseating the breaker on the bus.
I've seen the spring clip on the bus (input) side of the breaker go bad. It gets hot and that raises the resistance at that point further. This can go on until the tab on the bus becomes damaged due to the overheating. The breaker will have to be replaced in a new position. The old position on the bus can never be used again. Usually on crappy brand panels.
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I had this happen in a rental house I lived in about 10 years ago. I got home and the compact fluorescent bulb in the porch light was flickering madly and then found that other loads on that circuit were the same. Went out to the garage and I could hear a sizzling sound from the panel. Shut off the main and started looking around and found exactly that issue, and then noticed that the terminals in the vacant spot were burned as well. I ended up using an air powered grinder to clean them up and installed a spare breaker I had and it worked the rest of the year I lived there. I let the landlord know but they didn't seem real interested in dealing with it.
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Paul Hovnanian P.E. wrote:

The connection can get loose enough that there is arcing between the breaker and bus. You can hear a sizzling sound (not the normal humming). A bad breaker can be found with the old screwdriver-as-a-stethoscope trick.
"Very" hot is is subjective. Breakers have a thermal trip so they do get warm.
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bud-- wrote:

Flames coming out of the breaker box is another indication. :(
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First turn the breaker off and tighten the screw that holds the wire at the breaker. If it is excessively loose that probably fixes it, if not then.... Assuming you are using copper wire..... You need to measure the amperes going through the No. 12 wire with a clamp on amp meter at the breaker. If there is more than 12 amperes and the lights are on for more than 3 hours you should increase the size of breaker to 20 amperes. No. 12 is good for 20 amperes and good for 16 amperes for a continuous load (3 hrs or more).
The breaker and terminal should not be hotter than 60 degrees C. or 140 degrees F. Hot water from the tap is at about 160 degrees F so that should give you and idea. If the wire has an insulation of THHN, XHHW, THHW, and the breaker has terminals rated for 75 degrees C. and the wire is not part of a NM cable (commonly called Romex) and the panel is rated for 75 degrees then the breaker and terminal can be at 75 degrees C or 167 degrees F which is pretty darn hot.
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