Edison 3-wire ??

[61333]

Went on a Service call and found that when the Dryer is started, the voltage on the line side of the main breaker drops to 60V on one leg and 180v on the other. Then back to 118V and 123V when its running to ground. TV in the house gets louder for 20 to 30 seconds and then back to normal volume. Everything from the meter and the panel is tight and no burns on any of the wires. Does this sound like a like a power company problem ??

 

[iwire]

It is a bad neutral connection between the equipment and the transformer.

Could be in a feeder, panel, service conductors or the power company conductors.

I would start looking for it soon.

 

[LarryFine]

It is a bad neutral connection between the equipment and the transformer.

Could be in a feeder, panel, service conductors or the power company conductors.

I would start looking for it soon.

Agreed on all three statements.

Who's responsible depends on which side of the meter (here, anyway) the problem is.

That it happens at the main breaker is a sign it's probably the POCO's issue.

 

[fireryan]

Could someone explain how a loose neutral could cause this?

 

[LarryFine]

Could someone explain how a loose neutral could cause this?

Okay. The source of the power in your house is delivered by a 240 volt transformer secondary that has a center tap, which we ground and call the neutral. There is 120v between each line and the neutral, and 240v between lines.

If the neutral is broken, you still have the 240v between the hot wires, but the two 120v supplies are no longer locked in, so, unless the loads on each half happen to match, the voltage from each line to the neutral will shift.

The half of the service with the greater load (meaning less resistance) will end up with less than 120v across it, and the half with the lighter load will see more than 120v. That higher voltage is what tells us that it's the neutral.

How's that? If you'd like more, I can post a past ditty I once typed up for another neutral question.

 

[fireryan]

Thanks Larry I think I got it but if you wanted to post more I sure wouldnt complain

 

[LarryFine]

Click here.