Circuit Breaker heat output

[mgardner]

I am wondering if there is a temperature that indicates that a circuit breaker is overloaded. We are measuring the heat output on a circuit breaker by directing an infra red temperature sensor at it. I was told that if this reading was over 100 degrees Fahrenheit that a possible overload condition could exist. Then I was told that if it was over 120 degrees it might be carrying too much load or may have some other issue?

Please clarify for me

1. What does this circuit breaker temperature indicate?
2. What are the limits on this temperature reading, if there are any?
3. Should I worry about any of this?

Thanks for your help!

 

[mcclary's electrical]

100?????? it would read that on a hot day without being hooked up!!,,,,,You need to go by amperage readings to determine if it's overloaded,,,,not temperature. Whoever told you this is guessing

 

[drbond24]

I agree with mcclary. There isn't a specific temperature that is the cutoff for what is a problem and what isn't. Remember, your body is 98.6 degrees F. If the breaker is 100 degrees F, touching it would be very similar to touching your arm. Would you consider that temperature to be a problem?

If you're scanning electrical panels with an infrared gun, you're probably more interested in hot spots created by bad connections. Like mcclary said, if you want to know if a circuit is overloaded, slap a current clamp on it.

 

[LarryFine]

I, too, agree. There are several things that can cause a breaker to get hot without it being overloaded, such as poor contact with the panel bus, loose load connection, pitted/worn internal contacts, etc.

A breaker can trip because it should at that time, or it can get hot enough to trip even with current within its rating. Measuring current when it trips is the most telling of troubleshooting a hot breaker.

 

[76nemo]

I, too, agree. There are several things that can cause a breaker to get hot without it being overloaded, such as poor contact with the panel bus, loose load connection, pitted/worn internal contacts, etc.

A breaker can trip because it should at that time, or it can get hot enough to trip even with current within its rating. Measuring current when it trips is the most telling of troubleshooting a hot breaker.

Good post Larry.

 

[LarryFine]

Good post Larry.

Thanx! :smile:


(Gotta make a good post every once in a while. )