Ask Me Help Desk - Breaker Tripping

Hello, I'll try to be as detailed as can be. I understand how electric circuits work but do not have a lot of experience with troubleshooting them.

The problem is a tripping breaker whenever I turn on the associated ON/OFF switch.

The switch connects to a lightbulb fixture and another wire goes to a thermostat for an attic fan. When I flip the switch to ON a vibration can be heard for a half second and then the breaker trips.

So far all I have done is removed all the covers and checked to make sure the wires don't appear burned (they don't) and that all black wires are wired together (they are) and all white/ground wires are together (they are). I don't smell anything burning either. I did note that the attic fan motor coils appear brand new, so it's possible it's never worked in the 4 years it's been installed (I am 2nd owner).

The associated breaker is a 15 AMP breaker and operates the master bedroom, a closet light, and the attic circuit described. Breaker trips even if only thing turned ON is the attic switch. I do not know the AMP requirement of the fan, it's hard to get to, but will get that info if anyone thinks it's needed.

I'd really like to get the attic fan running, as the AC unit can't keep up with the heat :mad:

What you need to tell us

--------------------------------------------------------------------------------

Asking questions

If you think a multimeter would be useful in solving your problem state whether you have or do not have one.

I do not have a multimeter.

If you are in an area other than the United States and it’s not in your profile, this information might matter.

I am in Virginia

It appears from your description that the fan is drawing more than the breaker can tolerate, so it trips. I suspect the vibration is coming from a motor on the attic fan and that is overloading the circuit.

There's a very small possibility that the circuit breaker, itself, is faulty.

Do you have a test light?

Quote:

Originally Posted by Perito

It appears from your description that the fan is drawing more than the breaker can tolerate, so it trips. I suspect the vibration is coming from a motor on the attic fan and that is overloading the circuit.

There's a very small possibility that the circuit breaker, itself, is faulty.

Do you have a test light?

Thanks for the response!

I do have a test light but it was purchased from an auto parts store and have never used it on anything higher than a 12V system.

You could test the circuit breaker by replacing the breaker. You could remove another (known good) circuit breaker from another circuit in the panel and wire it to replace the one in the bad circuit.

The 12 volt test light isn't suitable for working on household circuits. You'll blow it up.

You mentioned that the fan motor appears brand new. That is curious. You should check to make sure it's properly wired. Make sure the fan actually moves. It might have seized up -- even if it it appears to be new. The sound (vibration) that you are hearing suggests the fan motor is not rotating. If you could confirm this (get close to the fan motor and ask someone to flip the switch), it would help you diagnose whether that is the problem.

Other than that, I think you're going to have to get someone with the tools to troubleshoot this.

Quote:

Originally Posted by Perito

You could test the circuit breaker by replacing the breaker. You could remove another (known good) circuit breaker from another circuit in the panel and wire it to replace the one in the bad circuit.

The 12 volt test light isn't suitable for working on household circuits. You'll blow it up.

You mentioned that the fan motor appears brand new. That is curious. You should check to make sure it's properly wired. Make sure the fan actually moves. It might have seized up -- even if it it appears to be new. The sound (vibration) that you are hearing suggests the fan motor is not rotating. If you could confirm this (get close to the fan motor and ask someone to flip the switch), it would help you diagnose whether that is the problem.

Other than that, I think you're going to have to get someone with the tools to troubleshoot this.

I did check the fan to see if it rotates and it spins easily. I'll try replacing the breaker after I double check the AMP requirement on the fan then will replace with a new one.

Thanks!