low voltage in ground circuit of residential wiring

Thread Starter

Teager

Joined Feb 22, 2007
3
Does anyone know if it is normal to have a small amount of voltage ie; 1-18 volts feeding back thru the ground wire in residetial circuits. I found an open ground in a junction box that feeds a few lighting and receptical circuits. I check it for a volt reading and got 12 volts. I thought there may be a problem with one of the swithes or fixtures so I disconnected one at a time and the volt reading went down as I disconnected each circuit. Is this normal? Any suggestions?
 

nomurphy

Joined Aug 8, 2005
567
It may indicate that there's a problem(s) along the line with the neutral connection, it's not conducting as well as it should, such as bad connections at the wire ties within a box.

Think of a ground interrupt wall socket, it opens (interrupts the circuit) whenever ground current exceeds a set amount, so there shouln't be much conduction along the ground wire (it is for safety, just as you may be experiencing).
 

wireaddict

Joined Nov 1, 2006
133
Where did you measure this voltage drop from, either side of the open ground connection, between ground and the hot [black] wire or between ground and neutral? If it's the latter, tighten all the neutral [white] wire connections on this circuit: all your outlet, switch and light fixture boxes and also your main panel including the main neutral wire from your meter socket. If the voltage reading is between the open ground and the hot wire, you probably have a little moisture that's leaking current; connect up your open ground here, as thingmaker3 said, and forget it, you should be good to go.
 

Thread Starter

Teager

Joined Feb 22, 2007
3
Thanks for the information and replys.
I checked the voltage initially between the two wires of the open ground, as I noticed a very small blue spark when I was grounding it. The voltage between the open ground wire to ground is 7 volts, the voltage from this open ground wire to hot is 20 volts, and it is 7 volts from the open ground wire to the neutral. I have noticed that as I disconnect an outlet or lighting circuit that the volt reading goes down slightly with each run that I disconnect, but no one run knocks it right down.
 

Thread Starter

Teager

Joined Feb 22, 2007
3
Thanks for the information and replys.
I checked the voltage initially between the two wires of the open ground, as I noticed a very small blue spark when I was grounding it. The voltage between the open ground wire to ground is 7 volts, the voltage from this open ground wire to hot is 20 volts, and it is 7 volts from the open ground wire to the neutral. I have noticed that as I disconnect an outlet or lighting circuit that the volt reading goes down slightly with each run that I disconnect, but no one run knocks it right down.
 

thingmaker3

Joined May 16, 2005
5,084
Voltage is always measured across two points. Ground is only 0 volts in relation to itself. Ground over there can be several hundred volts different than ground over here. (Always stay clear of downed power lines!)
 
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