For a long time I've had a hum eminating from where the hydro connection braces to my house -- not at the meter at the ground floor, but at the top of the pole where the cables meet the house, on the wall outside a second floor bedroom. Sometimes it hums, sometimes it doesn't, but when it does, it resonates in the bedroom. On a few occasions over the years I've had both hydro workers and electricians at my house to troubleshoot, but they can't explain why this happens. They've changed the meter a few times, put some padding between where the cables connect to the house -- but nothing stops it.
I've also noticed that some electric appliances create a hum when turned on. For example, I have two identical small halogen lamps, both illuminating different areas of a desk. Both lamps are on the same circuit, but one hums and the other doesn't (even if the non-humming one is off). I might've thought that perhaps the humming lamp is defective, but I've noticed this same hum with some (not all) other electrical appliances in the house (e.g. I just bought a ventless electric fireplace for the master bedroom, and it's humming too). I don't know much about electrical. Could it be an overall grounding issue? Surely this isn't normal??? Any advice is much appreciated. Thanks.
