Don't Wait Up wrote:
House is ~50 years old. Copper Wiring. On one 20a circuit there are a
number of duplex boxes. On three adjacent to each other the voltage
reads 120 -- ~40 -- 120. The previous owner switched one box to a
single receptacle and switch. And wired to the switch a lamp
(incandescent) in a new skylight. The operation of which has always
been problematic.

I tracked down the low voltage recaptacle when I move the refrigerator
plug to that outlet.

Any thoughts on this?
Thanks.

Does that 40V outlet work at all? Are you measuring it under load? Are
you using a digital meter? I suspect that outlet may not be getting any
current, but still will show voltage on a sensitive digital meter. A quick
check using an old analog meter would tell you what is happening?

--
Joseph Meehan

Dia 's Muire duit