20 volts neutral to ground

[bohl1076]

i'm having a problem @ my brothers house, one of his bedrooms, some of his recepticles are reading 20 volts to ground from the neutral, 120v hot to ground, and 90v hot to nuetral. anybody now why this might be happening, and how i can fix this. thanks

 

[iwire]

i'm having a problem @ my brothers house, one of his bedrooms, some of his recepticles are reading 20 volts to ground from the neutral, 120v hot to ground, and 90v hot to nuetral. anybody now why this might be happening, and how i can fix this. thanks

Classic example of a loose or disconnected neutral that is either part of a multi wire branch circuit, a feeder or the service.

 

[bohl1076]

so just process of elemination? or is there a way i could locate the problem conductor. also how does a nuetral pick up a voltage like that? i'm 90% sure i disconnected any and all loads on that circuit?

 

[ohm]

As iwire mentioned it's probably a loose neutral but two other posibilities are: 1) you're using a very high impedance input meter to easure this voltage and it may simply be stray leakage, capacitive coupling or inductance. Try loading down the the meter with a 10W lamp and see if the dpoblem doesn't go away. 2) on non-linear commercial/industrial loads such as computers, magnetic ballasts etc. (if measured as far away from the SE panel as possible, w/ a heavy load) it may reflect the need for a larger neutral (not likely in a home).

 

[bohl1076]

i tried adding a lamp, but got the same results.

 

[ohm]

Are you sure only one circuit is affected? If only one circuit, you can rule out multi-wire circuit problem.

Have you tried different high wattage loads to see if you can change your readings? I've had perfectly fine looking receptacles get hot and not pass power to the next receptacle in line, especially if they were on aluminum wire or back-connected devices (ugh).

 

[bohl1076]

im not 100% sure if it's the only circuit doing this right now, however i ran into this situation with another circuit at his house before, and was not sure what i did that fixed the problem. i just replaced all the old recepticals with new ones, and wasn't sure if thats what "fixed" it.
last week my brother painted a room in his house and wanted to update the recepticals, but couldn't wait for me to have a free day to come over and do the electrical. he tried to connect the new ones in the same order he disconnected the old ones. there wasn't any problems before he attempted to do this!!!

 

[76nemo]

Why are we suggesting high-wattage loads with the possiblity of an open neutral

 

[ohm]

im not 100% sure if it's the only circuit doing this right now, however i ran into this situation with another circuit at his house before, and was not sure what i did that fixed the problem. i just replaced all the old recepticals with new ones, and wasn't sure if thats what "fixed" it.
last week my brother painted a room in his house and wanted to update the recepticals, but couldn't wait for me to have a free day to come over and do the electrical. he tried to connect the new ones in the same order he disconnected the old ones. there wasn't any problems before he attempted to do this!!!

Sounds like you and your brother need to look at what he did.

 

[Buck Parrish]

Sounds like you will have to open all the outlets until you find the problem.
Chances are you will see a loose neutral, bad connection, short, or something a long those lines. Some times the problem is in the first outlet you check. And some times it is after checking many, which will be the last.

 

[ohm]

Why are we suggesting high-wattage loads with the possiblity of an open neutral

A high wattage load would make any high resistance connection upstream show itself. Mearly measuring the voltage or resistance downstream with a high impedance, high quality meter would not do ay good.

 

[bohl1076]

cool thanks for the input, i'm headed there right now. i'll let you know what i find!