Thread: Electrical panel

Good morning. What is happening when some of the breakers in a panel are warm or even hot to the touch?

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Heat is generated by the current flowing through the breaker. This heat is what causes a breaker to trip on overload.

Abnormal levels of heat could point to a problem.

Were they AFCI breakers?

Originally Posted by Jim Port

Heat is generated by the current flowing through the breaker. This heat is what causes a breaker to trip on overload...

Well, at least in many modern designs, not exactly, see for example:

HowStuffWorks "Basic Circuit Breaker Design"

Most all breakers of modern manufacture (that you're likely to find in a residence) have both a magnetic and thermal component to the trip mechanism.

An illustration that does not reflect actual trip curves but illustrates the point is a 15 AMP breaker may carry 16 Amps for many hours before tripping, but will trip much sooner with a 30 AMP load.

The magnetic component makes for instant tripping when a fault occurs.

Older breakers may lack the magnetic component

Originally Posted by Wade Johnson

Good morning. What is happening when some of the breakers in a panel are warm or even hot to the touch?

If there were lots of high intensity lights on for a long time, it might explain the problem. A Zinsco/Sylvania panel might be arcing at the buss bar connection. I would defer and have an electrical contractor look at it.

I had an electric water heater turn on while I was inspecting a panel and the 30 Amp breaker heated up to about 100 degrees.