The longer I live here.............
Two weeks ago, I plugged a light into an outlet in my kitchen. The light had a short in it, and it receptacle sparked with electricity, then smoked, then died. This also blew the fuse in the old-style fusebox I have, and tripped the circuit breaker in the electrical sub-panel in the garage. I replaced the outlet and fuse, and tried to turn on the switch in the sub-panel. SPARKS! FIRE! SNAPPING ELECTRICITY!
I got an electrician, which I feared was going to be a costly endeavor. He checked my new outlet, and found it had been installed right. So why didn't I have power.
Well...... First, my electrician told me that the sub-panel in the garage was not a sub-panel. It was the main. (My home inspector fucked up that designation.) Second, and good news, it was exceedingly well-grounded. Third, the fuse box in the house is really a sub-panel. It used to be the main, but it isn't any longer. Fourth, We went inside the housed, and looked at the panel beneath the stairs. That's another sub-panel, he said. He then pointed out to me that all my outlets in the kitchen are grounded. They aren't GFCI outlets (the ones with the little fuses in them), but they were grounded. He showed me where on the stairs sub-panel the kitchen outlets fed: LO! BEHOLD! There's a GFCI there, as well as a circuit breaker. The electrician did it this way, he explained, because GFCI outlets are bigger than normal outlets. They'd have had to cut through the wall and tile to put GFCI outlets in the kitchen, which (given the age of my hosue -- nearly 90 years) would make for some major repairs. So I'm completely protected, just as if I had GFCI outlets in the kitchen. It's just done differently.
He then showed me that the circuit breaker on the stairs sub-panel had tripped. "This is your real circuit breaker for the kitchen," he said. He reset it. I had power in my kitchen again!
He then took me to the garage. He explained that my garage door opener is pretty old. Older electronics like it need to be grounded. But they use so much power, they need to be grounded in a special way, using what's called a "dead-wire". If these electronics short, they send a huge amount of power into the ground-wire. Since it's unsafe to pump this into the ground, the ground-wire -- or dead-wire -- is instead routed back to the circuit breaker. So if a short occurs, the electricity is routed back into the electrical main (where it can be absorbed safely).
The switch I'd tried to reset? It was the dead-wire. When I pushed the breaker closed, it forced a huge amount of electricity to surge through the dead-wire and into the main. This is what caused the spark and flash of fire.
He relabeled the circuit break panel so it showed the dead-wire. He also moved the circuit breaker opposite the dead-wire. That way, if some idiot did try to flip it in the future, the spark and fire would't damage the actua live, useful circuit breaker opposite it.
Total cost: $120.
I learned a lot about how electricity works in my house. I learned where everything is, in case I need to flip a switch in the future. And I have power in my kitchen outlets again.