I got a call to check out a power problem at a townhome in the Salmon Creek area of Vancouver, WA. The customer said that the power to the upstairs bedrooms goes out and she has to reset the breaker for it to come back on. She mentioned that some siding work had been done recently and there were no power issues before this work was done. She thought maybe a nail was shot through a wire during the residing process and was causing the breaker to trip.
I went out to see what the problem was and asked her to recreate the problem. She plugged in her flat screen tv and turned it on and POOF! The breaker tripped! Just like she said. This intrigued me as a flat screen tv should not draw enough power to trip a breaker, so I went to the panel to do some more investigating.
I noticed that the breaker that tripped was an arc-fault breaker. Arc-fault breakers are designed to detect a short between the neutral wire and ground. This is important because the neutral wire is what carries any unused electricity back to the panel and if it shorts out, that unused electricity can go elsewhere, like into you, in the form of an electric shock. Normal breakers only detect shorts between the hot wire and ground. Arc-fault breakers are required for circuits in a home that are powering lights and plugs in bedrooms and closets.
There was another arc-fault breaker in the panel so I switched the wires between the breakers to see if maybe we had a bad breaker. It still tripped the other breaker so I knew the breaker wasn’t bad.
I put the wires back to their original position and plugged the tv into the other arc-fault circuit to see if the wiring in the building was at fault from a nail shot through during re-siding. It still tripped the other circuit so I knew the wiring in the building was okay.
The conclusion was that there was a short in the tv somewhere between the neutral and the ground and it was causing the breaker to trip when the tv is turned on. Unfortunately, the only solution is to get the tv fixed or replaced. The good news is, the wiring in the building is still ok and the siders didn’t damage any wiring with rogue nails.
If you’re ever having problems with a particular piece of equipment, try plugging it in to several different circuits to see if the wiring is at fault or the equipment. It will save both of us time and money.