You might have some other electrical device plugged into another outlet in the house causing the problem. Anything with a large motor, or even a small stepper motor, can cause noise to be induced on the line.
2 things to try:
Turn off every circuit breaker (or remove every fuse) in the main panel, except for the one that the sub is plugged into. Make sure that the sub is the ONLY thing plugged into the 1 remaining circuit. If the hum goes away, turn the breakers back on one by one until the hum comes back. Then, you will have an idea where to look (if your panel has labels).
Second (maybe 1st) verify that your main electrical panel has a thick, bare, copper wire coming out of it that attaches to either a water pipe on the inside of the house, or a copper rod stuck in the ground on the outside of the house. If you don't see one, or if the connection you see looks bad, call an electrician. Your whole house could have a floating ground. If you have cable TV, it should also be grounded. Noise can come in on the ground (shield) as well.
(I forgot to ask... Are the AC grounding requirements in Canada similar to those in the U.S.?)
Good luck,
Last edited by Michael_A; 05/18/04 01:11 AM.
