On May 15, 7:21*pm, TimR wrote:
The back porch light stopped working, a new bulb didn't help.

So. *I put a meter on the socket. *0 V.

I pulled the switch plate off (just a normal single pole). *80 V
terminal to terminal. *Hmmm?

Killed the power, put an ohmeter terminal to terminal, infinite
resistance at both switch positions. *Diagnosis bad switch, supported
by the fact that before it died completely, flipping the switch
several times made it work. *Besides I've always had a CFL in that one
and I suspect the capacitor shortens the switch life due to arcing.

Okay, a new switch is $1.29, no big loss if wrong. *Took the old
switch off, turned the power back on and checked wire to wire just for
grins, still 80 V. *Uh oh.

Put the new switch in. *Turned power on, checked the socket, 120 V.
Put bulb in, (CFL), lights up fine.

Well, I have a working porch light again, but I'm left with the 80 V
mystery. *I don't know any way to get 80 V on a normal residential
power setup. *The meter was a digital Radio Shack multimeter. *If I'd
had time I'd have checked again with the Simpson analog, digitals
sometimes give funny readings, but I've never seen 80 V. *What am I
missing?

If you measured across the two wires that were connected to the
switch, you're measuring the potential from hot *through the bulb* to
neutral. If you want to sleep better, pull the switch off again and
measure from hot to ground, you should then read 120V or thereabouts.
If the bulb is a CFL there may be some odd effects causing an
incorrect voltage reading the way you measured it.

nate