I found this site because I "Asked This Old House" I love it and will become a frequent visitor.
The other day it was warm (34 F) and the ice/snow was melting. I reached down to clean out some leaves in my down spout on my aluminum gutter and I received a shock. I quickly grabbed my meter and with the black probe stuck in between the slabs of concrete, I touched the red probe to the metal on the gutter and got 50 volts.
I then turned off the main breaker at the electrical panel and tested again no voltage. I started to turn on breaker by breaker and found the exact break that was causing the issue. That breaker is for 5 ceiling lights located on the 1st floor in the same corner as the gutter down spout.
My next step was to remove the screws holding the brackets in place for the gutter downspout. I thought maybe one is screwed into a wire. That did not fix the problem. At that point I tested again, with black probe stuck in the ground again I touched the ladder, 50 volts, then I touched a metal hinge on my wooden fence, 30 volts. The actual ground is electrified.
The worst part is if I turn off all breakers on the panel except the one causing the problem and turn off all lights on that breaker (I don't believe any outlets are on that breaker) I see the electric meter spin. I am using power due to the problem. Two days after the problem it got below freezing and the ground dried up. I could not get a reading using the same techniques. It seems to only happen when it rains or is wet.
The house is stucco on the outside and plaster lath on the inside. The circuit panel is newer and all the wiring in the basement is newer, but most of the wiring in the house is old. the problem does not exist with any other downspout. In the problem area there is a detached garage (on a different breaker) with in 4 feet and the main power line and ground with in 3 feet. Can anyone help?