I was trying to hook up an extra receptacle in my garage. Above it I found a line that I thought was live. I have a little meter that you hold up to the wire (non contact) and it makes a fast beeping fast flashing noise if it is live. It seemed to register live, but not as fast as other lines that I tested. To make a long story short, there wasnt much on the line, I could actually touch it with my bare hands and not feel a thing.

Could it have been a 12 volt line?? the wire seemed like regular 12-2 wire, but older (the house is nearly 50 years old) It was a white wire.

Also, the wire was actually joined in a junction box in the attic to a similar wire. BOTH wires registered as live, or almost live, even when disconnected from each other.

There had been water damage. Could water damage the breaker box and produce this problem? or a bad ground?