"E Z Peaces" wrote in message
.. .
Jim Beaver wrote:
I've got my Christmas tree set up in my living room. A couple of strings
of lights (not those mini-lights, but the finger-tip size bulbs).
Here's the problem:

When I turn on the lights, a loud hum arises from the timer for my yard
sprinklers. This timer is mounted on the outside wall of the living
room. Obviously it's on the same circuit, as the hum comes and goes when
the Christmas tree lights are turned on or off.

The hum is loud. Probably loud enough indoors to wake a light sleeper
from a nap if it suddenly came on. It's even louder, of course, outdoors
near the timer.

The power cords, plugs, and receptacles all seem cool. So I'm wondering:
does this sound like an overloading problem, or more likely some sort of
simple harmonic vibration? Am I in danger of fire, if everything I can
get to seems cool?

I don't know anything much about electrical testing or I'd use a tester
on it somehow. But I don't really know what to look for.

Anyone NOT doing something more interesting on Christmas Eve who wants to
advise me here?

And with that in mind, happy holidays to all here. Thanks.

Jim Beaver

I haven't been able to imagine how the lights could affect voltage or
current in the timer.

Are there valves near the timer? Sometimes a solenoid valve can hum
loudly.

I discovered this morning that the hum doesn't happen in the daytime. Which
leads me, genius that I am, to conclude that it's not the sprinkler timer
but the low-voltage outdoor lighting system timer. I have no idea whether
this affects matters much in terms of safety, etc.

Jim Beaver