Go Back  DoItYourself.com Community Forums > Electrical, AC & DC. Electronic Equipment and Computers > Electrical - AC & DC
Reload this Page >

Help! Ghost electrical problem, low voltage or voltage drop Main Panel Question

Help! Ghost electrical problem, low voltage or voltage drop Main Panel Question

Old 03-22-13, 08:31 AM
Thread Starter
Join Date: Mar 2013
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thumbs down Help! Ghost electrical problem, low voltage or voltage drop Main Panel Question

So 50 yr old house, never had an issue with anything. The other day I took some time to redrywall a room and noticed old 220V lines running that were no longer in use. Took up 4 breakers in the box. As a son of an electrician, I took the time to take out the breakers and the wires to those unused lines. Had to turn off the main breaker to do it.

A few days later I noticed a drop in electric from a few rooms. Another outlet farther down the circuit was still in use, I was baffled at what it could be. Along with this drop out overnight (literally went to sleep fine, woke up powerless) I noticed using the electric dryer that the lights would come back on...

The dryer are the only breakers on the Left bus bar side.
The rooms are on the Right bus bar.

The left bus bar reads 123.2V or so at the main.
The right bus bar reads .245 V or so coming out of the main.
Does this mean I have a Main Breaker issue not distributing the power correctly? Are these two situations just linked due to bad timing? (removing those breakers from the left side of the panel). The electrical worked fine for 5 days after I removed those unneeded 220V lines.

Any help or questions answered would be appreciated.
Attached Images  

Last edited by Gary Long; 03-22-13 at 08:58 AM.
Old 03-22-13, 10:35 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 63,896
Received 3,750 Upvotes on 3,362 Posts
Welcome to the forums.

It sounds like you have lost one of the legs of your 240 volt service. It's very hard to see any detail in your picture but you'll need to check the incoming wiring to that box for power.

Check the wiring on the right side of the breaker. That appears to be the incoming lines.
There are jumpers from the output side of the breaker to the buss bars.

I re-sized and marked your picture. It looks like the lugs on the line side of that main breaker are corroded. Still hard to see any detail.

The buss bars alternate behind the breakers.
So the first set of breakers down, left and right side, are on the A buss.
The second set of breakers down, left and right, are on the B buss
The third set of breakers down, left and right, are back on A buss.
and so forth down the line.

When you turn your 240v dryer on....it's connected across the A and B legs which effectively forms a bridge between the two legs. That will cause a ghost voltage.
Attached Images  
Old 03-22-13, 01:26 PM
Join Date: Dec 2010
Location: usa
Posts: 206
Upvotes: 0
Received 0 Upvotes on 0 Posts
A lot of times if you turn off an old main breaker they will fail to reset, and that may be what happened here if you are only getting voltage on one side of it. A lot of parts in those breakers...They take a lot of heat over the years. You might try resetting it a couple of times..But if it does not then time to buy a new main. I assume you have checked the power going INTO the main?

Last edited by JimElectric; 03-22-13 at 02:11 PM.
Old 03-22-13, 06:33 PM
CasualJoe's Avatar
Join Date: Jan 2010
Location: United States
Posts: 9,842
Received 179 Upvotes on 162 Posts
Judging the condition of a panel from just pictures isn't always the best thing to do, but in this case I think that rather than replacing the main breaker, I'd replace the entire panel and breakers. There's a very good possibility that a new panel would be less expensive than a new main breaker anyway.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: