bad voltage in garage

[danmc9]

I have a service garage with 3 bays. A 400amp
single phase service. There is a ground rod. I am
getting 145v on A phase, 94v on B phase, 240v
A-B. Same voltage measured to neutral or ground.
0v neutral to ground. Lighting is T12 two
lamps , 8 feet. If i turn off breaker 2(half of lights),
A-146v, B-95v. If i turn off breaker 4(half of lights),
A-109v, B-131v. I need to turn off 2,4 and breaker
for gas furnace to get A-122v, B-117v.
Can capacitors cause this?

 

[raider1]

Check for a bad neutral connection.

Chris

 

[danmc9]

Neutral in panel and at meter are good.

 

[Dennis Alwon]

Neutral in panel and at meter are good.

I would bet that there is a loose connection on the neutral. You will not see it with no loads as the voltage- I am betting -- will be normal with no loads. It is more common a utility neutral problem.

 

[billelectric]

as you turn off breakers the load(resistence) changes. with a bad neutral connection,the voltage balance will change, from a to b phases as loads change.

 

[jumper]

Dan, watch this demo on a bad/broken neutral connection.

Created by member 480Sparky.

http://forums.mikeholt.com/showthread.php?t=89280&p=711889#post711889