"Reed" wrote in message
k.net...
Jim Beaver wrote:
I put up my Christmas tree yesterday, with two strings of lights, each
string plugged into a separate socket on the same receptacle. About
three hours after turning the lights on, I noticed a low humming sound
coming from the room. When I unplugged one string of lights, nothing
happened. When I unplugged the other string, the humming stopped. Plug
it back in, the humming starts again.

Now here's the weird part (at least to me): the humming is not actually
emanating from the lights, the cord, the receptacle or anything else on
that entire side of the room. The hum (which is quite noticeable) seems
to come from near the ceiling 3/4 of the way across this 17-foot-long
room. The hum is present whether the regular light fixtures are on or
off, and there's nothing else electrical in the room.

The hum is just loud enough to cause me some concern -- not from the
noise (which is not unpleasant) but from its volume, which is enough to
suggest that something conceivably might not be safe. But I'm completely
stymied by the fact that the Christmas tree seems to be a ventriloquist,
throwing the noise some ten feet away. (Literally, I can stand "between"
the tree and the hum.)

Any ideas?

Jim Beaver

Some questions:
If you trade the strings vs sockets, does hum stay with outlet or string ?

The sound stays with the socket, not the string.


If stays with string, what is different about it from other ?
Have you tried any other lights, etc in same socket ?

No. Will try.

What is above ceiling at point of hum ??

I've now actually tracked the sound to a wall on the exact diagonal opposite
side of the room. There's another outlet there. The hum is very loud
(comparatively) at that point. The outlet is cool to the touch. On the
opposite (house external) side of the wall from this new socket is the timer
assembly for my sprinkler/yard-lighting system. Coincidence?

Are sockets controlled by a switch ??

No.

Is house wiring aluminum, or copper ?

I don't know, but the wiring is approximately three years old (the age of
the house).

Does this branch circuit have a GFCI ?

Not as far as I can determine.

Jim