One of my kitchen sockets--or rather, the box to which it's attached--has begun to quietly beep, even when nothing is plugged in. The pattern is: 1 beep, silence, 2 beeps, silence. This cycle repeats about 28 times a minute.
Shutting off the circuit stops the beeping.
As a first step, I tried to remove the socket:
But as you can see, the white and black wires are connected behind the cabinet wall, to this:
It's this box that's doing the beeping.
How do I fix this?