This was a good lesson learned for me so I'm sharing it here, just another slide for the ole' mental slideshow. For you electricians out there you'll know what the problem was immediately. It took me awhile.
I was just starting a 72 hour shift at the fire/rescue helicopter. People staying at the cabin (my first owner builder project, finished in '03) called to say smoke was coming from their power strip. So, I thought, you have a bad power strip. Then they called to say the microwave was smoking, and they never used it. Hmm...I'll look at it in three days when I get off work. Next call, half the lights in the house were really bright; the rest were really dim. Some were coming on by themselves. They thought the place was haunted.
Really bright lights, to me, represented a serious enough symptom to get someone to cover for me to make the hour drive home.
My meter is at the pole I put in, then aluminum wire runs overhead to the cabin into a subpanel. One leg showed 18v. The other showed 202v. It showed 220 potential between the legs as it should...I watched my meter as I shut off breakers one by one, thinking one of them would eliminate the problem, then I could trace where things were crossing over. (Again, you electrically savvy folks already see the obvious. For those that don't, these clues will point to a classic problem)
I had lost my neutral leg.
See, both your hot legs return through the common neutral. It's good to balance the two sides; I understand the house will actually use less electricity if your two hots draw the same amount of power...Take the neutral out at the pole, and everything returns through the common in the house back through the other leg----hence the high voltage and low voltage.
A tree branch had been beating up against my drip loops at the pole where the dielectric acorn nuts join the copper wire and the aluminum wire coming from the panel. After re-greasing them with the dielectric goop, tightening the acorn nut, and re-taping it, everything worked great. I went back and re-tightened all the connections, too.
Total losses were a power strip, a microwave/range hood, and 5 hours away from the paying job.