Electrical Wiring in the Home/Residential Wiring


Brother overloaded a circuit with a belt sander.  Reset breaker.  Now the light switches and the top and bottom of the stairs on the same circuit trip the breaker immediately.  Breaker replaced.  Outlet works.

The switches in question should be on a three-way circuit. Meaning both switches control the same light. They both have travelers between them.

This must be an older home because the lighting circuit and outlet circuits are on the same breaker.

When you run a large amount of amps through wires not designed for a large amount of amps they heat up. When they heat up they can physically move, they can melt insulation, they can burn off of the screw they are attached to, and they can melt wire nuts.

You will need to examine the wires in each switch box and in the light.

It sounds like a wire or some wires are shorted.

To trip the breaker immediately means there is a dead short. Either the hot wire is touching a ground wire or a neutral wire.

This could be because a ground wire moved over in one of the switch boxes and is now touching a wire on the switch.
A wire nut may have melted and allowed wires to touch.
A wire may have come loose from a wire nut.
A wire may have burnt off and is now touching another wire.

Make sure to examine both switch boxes and the light. You could have multiple problems, especially since you heated up all the wires on that circuit.

Check the wires with the power off.
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Electrical Wiring in the Home

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Greg Hughes


Troubleshooting electrical including appliances and HVAC.


34 years of experience.

Both college and tech schools in this field.

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