Mom called me and said a light and electrical outlet had quit working.
The light and outlet are part of a wet bar area in her dining room.
Using a volt meter I got a reading of 80 volts at the switch and 80 at the outlet.
The breaker for this circuit is a GFI and I got a reading of 120 volts at the breaker.
It’s a 15 amp breaker and 14 gauge wire going to the light and the outlet. They’re on the same circuit.
Why am I getting a reading of 120 at the breaker but only 80 volts at the switch and outlet?
Thanks for any thoughts on this.
^^^^^^
a Smith & Wesson beats four Aces
Replies
Which wires are you measuring between, at both the panel and the switch, and with the switch on and off?
Is this a three way switch?
I took a reading at the hot wire (black wire) and the neutral (white wire) at the breaker and got 120 volts.I pulled the outlet and switch (not a three way) and took at reading at the hot wire (black) and neutral (white) and it read 80 volts, at both the switch and the outlet.I assume the wire has broken or burned in two some where between the electrical panel and the other end of the circuit at the light switch and outlet.I don't own any fancy electrical equipment to test the circuit.It's a GE panel and the house was built in about 1976.Thanks for any input.^^^^^^
a Smith & Wesson beats four Aces
MrF...
If as you originally stated, the outlet is dead, but you're still reading something, guaranteed DanH is correct and you're reading a phantom voltage. Bet you're using a digital voltmeter? Can't do it...use a solenoidal tester (eg a Wiggie) or just a test light (preferably an incandescent rather than a neon). A digital meter just will not give you a reliable indication of the lack of voltage in this case...
PaulB
Yes, that's correct I was using a digital voltmeter.Okay I'll assume the reading of 80 volts is phantom and
there's really no voltage present at the switch and outlet.I believe I've ruled out the following:1. breaker2. outlet 3. switchI'll do a visual examination of the wire starting at the panel in the basement.I'm guessing I won't see anything such as a burned wire but I'll take a look. Maybe I'll look closely at places where it's stapled. That sounds like something I would do - drive a staple in too deep and cause a short.Thanks for all the input everyone.
^^^^^^
a Smith & Wesson beats four Aces
First thing I'd check is the actual wiring connections at the GFCI breaker. Note in particular that the neutral wire is supposed to be tied to an extra terminal (may be either a screw terminal or a pigtail) coming out of the GFCI breaker.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Edited 2/27/2007 6:20 pm by DanH
Thanks Dan and I'll check the connections at the breaker. Are you saying it's impossible to have 80 volts present in the circuit?Thanks again!^^^^^^
a Smith & Wesson beats four Aces
Not impossible to have the 80 volts, since obviously you measured it. It's real in that sense. But it's almost certainly "phantom voltage" and there's an open connection somewhere (open breaker, open switch, bad connection, etc).A broken or burned out wire in the middle of a run would be incredibly unlikely (unless the wire had been damaged somehow -- eg, with a wayward drywall screw). Most likely is a wire-nutted connection coming apart, or an iffy screw connection working loose. After that, you occasionally have a wire break or burn out where it was nicked or stressed while stripping the wire or attaching it to a terminal.And of course, if you used "back stab" connections anywhere those are very suspect.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
I pulled the outlet and switch (not a three way) and took at reading at the hot wire (black) and neutral (white) and it read 80 volts, at both the switch and the outlet.
Are they in the same box?
How many wires are in the box with the switch? Does the voltage reading vary if the switch is flipped?
If you have only one cable (i.e. one black and one white) into the box with the switch, the white is acting like a hot (assuming the switch is wired correctly). While it is supposed to be taped or colores to indicate black, often they are not. If you are measuring the voltage across an open switch, you often will get odd readings.
Sigh... The 80 volts is "phantom voltage". There is an open switch or connection somewhere.
http://en.wikipedia.org/wiki/Phantom_voltage
For whatever reason, more often than not its turns out to be neutral wire.
At the time the ligh/outlet went dead was there any recent nailing done in the house? A new picture, or something? Is it possible a nail or something broke the wire? Is the wire exposed anywhere where something may have hit it, or slammed in it breaking it?