Earlier today, I read Acceptable ground to neutral voltage?, and thought it'd be fun to stick my multimeter in the socket and have a voltage to report back. Neutral to ground read 60 volts. My head went into a bit of alarm. Yet, I can't find the answer just yet.
My apartment is old... as in it has a coal door and electricity wasn't an original feature. The basement has very old circuit breaker boxes and almost all of the structural wiring down there is old school fabric insulated wire on ceramic knob and tube wiring. It seems likely that most outlets don't have a real ground. All of them are GFCI branches.
The following measurements are all digital multimeter outputs.
Hot <-> Neutral: 118 volts Hot <-> Ground: 60 volts Neutral <-> Ground: 60 volts GFCI: trips internally, does not trip externally
Shorting neutral to ground with a 1 amp fuse did not cause the fuse to blow. Inserting a plug tester resulted in the middle light being solid and the two outer lights flickering. Hot to neutral measures 60hz. Other combinations vary wildly into the khz region.
Hot <-> Neutral: 118 volts Hot <-> Ground: 80 volts Neutral <-> Ground: 15 volts Sink <-> Ground: 15 volts Sink <-> Hot: 113 volts Sink <-> Neutral: 0 volts GFCI: trips internally, does not trip externally
Works properly. Measured resistance between ground and sink is 450k ohms. Hot carries proper voltage to neutral, ground, and sink. No voltage neutral to ground or sink, or ground to sink.
Can anyone make sense of these readings?!
Ground <-> disconnected 50ft length of extension cord: 24 volts Ground <-> disconnected 50ft length of extension cord: 17-21 volts Bedroom ground <-> kitchen ground: 60 volts Bedroom ground <-> water pipe: 60 volts Bedroom hot <-> water pipe: 0 volts Bedroom neutral <-> water pipe: 113 volts Bedroom hot <-> water pipe: 2.8 mega ohms Bedroom neutral <-> water pipe: lower and wildly varying Bedroom ground <-> water pipe: OL / unmeasurable ohms
Sooooo... I currently guess that I probably have hot & neutral reversed through most of the house and ground is unbonded. I still can't figure out the 60 (15, 80) volt readings though unless it's capacitive (re: voltage read across disconnected wires). I suppose I'll get my hands on an analog meter to test with next.