[Shawn]

Help! I can't quite figure the culprit of a 120VAC house electrical problem here.

It started when a microwave oven begin to trip a circuit breaker. The oven itself is about 5 years old, hardly used, and is installed above the stove (it has a fan, lights, etc.).

For whatever reason, this microwave overn has it's own 15A breaker. After reseting the breaker a few times, I took a close look at the breaker panel outside of the house. I noticed what appears to be some melting or burning of the insulation of the wire right up near the point the wire is secured to the breaker.

As a test, I started the microwave and ran around to the breaker and put a finger on the insulated part of the wire. Sure enough, I could feel the wire getting very hot. Thank goodness the breaker was doing it's job.

Now the question; what do you think could be causing a current draw so large from a microwave that it heats up the wire and trips the circuit? Could it be something other than the microwave itself?

Thanks in advance for any thoughts - I'll be away until Sunday evening and will check back then.

[Skibum]

My guess would be high resistance at that connection to the breaker. Take the wire out and re-seat it. (You arent an aluminum wired house are you?)

[WayneW]

Or a bad breaker (maybe high internal resistance)? Any chance you can swap this load wire with another breaker next to it and see if the heat follows the wire or stays with the breaker?

Maybe inspect how this breaker is attaching to the main bus bar (be very careful, especially if you have never replaced a breaker).

[Shawn]

Thanks guys; you were both right.

I inspected the breaker again this morning a little closer by removing it from the panel. The wire was not even being held to the breaker by the screw, it was just kind of shoved into the hole near the terminal. Damn if that in itself isn't scary, obviously a minimum wage employee wired my house.

Anyway, after fully removing the breaker I found that the screw terminal was fully closed and could not be opened, as evidenced by the stripped screw head on the terminal.

So, down to the hardware store and 15 bucks later I installed a new breaker, seated it correctly, cleaned and installed the wires.

Needless to say I also did a complete inspection of the rest of the breaker box hoping to prevent my house buring down in the future.

Thanks very much for your wisdom and expertise on the matter, it really made a difference.

Shawn

[Jay]

Soy el electricista que instaló eso. Soy salario mínimo pagado. ¿Qué esperaste?

[Shawn]

Si' senior Jay.

As a matter of fact, I found the electricians certificate of complaice with the uniform building code in my electrical panel:

[Jay]

[Jay]

and I want my Corona back.

[Skibum]

What's a Coronaback?

[Jay]

pity the unfortunate monoliguistas

This post has been edited by Jay: 10 July 2007 - 05:56 AM