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Joined: Sep 2007
Posts: 5
Chris21 Offline OP
New Member
I am an apprentice electrician. I only have 1 1/2 years experience in new residential contruction. I live with my parents. They have a problem. Lights flicker and sometimes power is lost to some things but not others. No circuit breakers are ever tripped. The power comes on to whatever is affected usually within 10-15 minutes. More than one circuit is affected by this. I replaced their old Zinsco circuit breaker box because I've read that this could be a source of the problem and sice I've read where they are a fire hazard anyway so I thought it would be the first place to start. Although the house is old and has the main breaker located outside the house. I did not replace that. Any ideas where to start? Undervoltage problem from the power company?

Joined: May 2005
Posts: 706
As you've replaced the distribution panel, the next guess would be the main, or the utility transformer connections. It helps if you can get a meter on it when it happens.


Joined: Nov 2005
Posts: 827
Do you happen to have a couple 120VAC and 1, 240VAC cube relays lying around? You could hook the coils L1-N, L2-N, & L1-L2, via the 'a' contacts. Use #12 and wire on the load side of breakers for safety. Jumper the 'a' contact of each relay to seal it in and walk away. Indicating relays would add style points. Losing a 120VAC and the 240VAC relay means your losing a leg. Just a 120 relay dropping would clue you in to the nasty floating neutral.

Joined: Aug 2006
Posts: 356

Sinec you have flickering i would say there is a loose connection on that circuit. You need to take out all of the devices from the each box and check the connections. I bet you that one of the connections is burnt or almost there.

Loose connection.

It is good that you have replaced the ZINSCO, but for future i would not start out by replacing the panel.

Be kind to your neighbor, he knows where you live

Joined: Jun 2005
Posts: 821
I would start by checking your voltage at the panel. Check one leg to ground (120), then the other to ground (120), and finally both to each other (240). Then check each individual circuit breaker. If all that checks out, then I would locate the branch circuit that's giving u the problem and shut that breaker off. Only then would I start removing devices to check for good terminations. Probably a stab-lock somewhere, lol.

Joined: Sep 2007
Posts: 5
Chris21 Offline OP
New Member
Thanks Tiger, joe, niko.

Niko, I have intermittent flickering lights and loss of power on more than one circuit. Replacing the box was something I wanted to do anyway so I figured I would start there.

Any other thoughts anyone?

Joined: Oct 2005
Posts: 40
Hello Chris,
I would borrow a multi-meter from someone at work and take some voltage readings. If the lights flicker so often, wait around for it to go crazy and take some meter readings. Since you said the problem is on multiple circuits, I would pull the cover off the outside main and meter pan. Check for water damage or corrosion on the equipment. Sometimes water gets into old services and makes a muck of everything. And last, make sure you have a good nuetral and that you have good ground connections, via the electrode and water main. You could have a bad nuetral somewhere. These are just a fews things you can check. Some of the guys will have some other good recommendations also.


Brian Gibbons
Joined: Jun 2007
Posts: 301
Multiple circuits indicate to me that it is a main power supply issue. Service, Main Panel or Sub panel if present.

I had a customer some years ago with the same issue. After several visits I had no idea what the problem was.
The customer made a comment that "it seems to happen on windy days".
So I went back and visually inspected the incoming power from the service all the way back to the transformer. While standing under the XFMR I heard a cracking sound. (electrical) short.
Called POCO and they found that the service wires on the secondary had worn enough for them to short to each other intermitantley.

Moral of the story. "It's not always your problem, it could be theirs"

If the customer would not have mentioned windy days, this would still be happening. Go outside and have a good look around. But don't touch anything you are not trained to work on......Good Luck

Last edited by JValdes; 09/19/07 01:34 PM. Reason: spelling
Joined: Sep 2005
Posts: 120
Zog Offline
Maybe your parents are screwing with you :-)

MV/HV Testing Specialist, "BKRMAN"
Joined: Aug 2006
Posts: 356
Are you sure they are physicaly on two different circuits?

I just want to make sure, because some people call receptacles and lighting two different circuits even though they are one.

I just want to make sure that we all are on the same page.

If you can get a hold of a meter that has recording capability. (Max, Min, Average) hook it up at the suspect circuit, turn on a resistive load (hair dryer) inside the house and see the voltage reading on the meter. If you have a large voltage drop at the output of breaker then move the meter to the bus bar, if you still have large voltage drop then call POCO.

Now, if you don't have large voltage drop at the breaker but have flickering lights inside the house (with your hair dryer on) then the problem is inside.

I am suggesting a hair dryer because it is large load and you want to put some strain on that circuit in order to create loose connection or flickering effect on that circuit.

Be kind to your neighbor, he knows where you live

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