What could the cause of an electric hum in my bedroom wall be?

Question

I'm sure it's local to my apartment only, and must have something to do with the wiring in the wall. I removed the fuse for the bedroom and the noise stopped.

Is this something that can be fixed? It's an annoying constant sound that often keeps me awake at night.

Answer 1

Check for bees, I had that humming noise, and it turned out to be bees had nested in the wall, had to call an exterminator, who cut a little small hole in the wall, stuck a tube in with the fluid to wipe them out.

If they were honey bees, I would have had to call a bee keeper.

Answer 2

It sounds like it could be a control transformer for your air conditioning.

They will hum and sometimes the noise will transfer through the walls.