DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Electrical (
-   -   What causes 1/2 of 220 to fail intermittently? (

Ehelper 02-14-2010 04:49 PM

What causes 1/2 of 220 to fail intermittently?
Hi all; first post here. A friend has a real head-scratcher. The old house had a new 100 amp panel properly installed a few years ago, all was well. Lately, the power to 1/2 the 110 circuits will all go dead at random (usually at night when its cold) The circuits affected are all on one side of the 220 main. We called the power co, they came out and checked their side of the service, said it was OK. We called an electrician out, he checked out everything from the meter to the panel and said it was OK. Here's the kicker: when the these 110 circuits go dead (living room, dining room, bedroom outlets, bathroom power and light) the tenants report that if they turn on the clothes dryer (220) the power to all the affected circuits comes back on!!! Anybody have any ideas what could be causing this? Could the main breaker have a bad contact? No breakers have ever tripped. Thanks for your help.

kbsparky 02-14-2010 04:52 PM

Turning on the dryer will cause a backfeed through the element thus making it appear that the non-working circuits are restored. Don't let that fool you. They dryer is not heating, and those "restored" circuits are not operating at full capacity.

You have a supply problem, which is probably outside, considering that it fails when its extremely cold. I'd call the POCO again, and have them check their connections from the meter back to the transformer. Call `em while the affected circuits are acting up.

A couple of things to try while it's acting up:

1) Beat on the meter with the palm of your hand -- a loose connection in the meter socket may be restored momentarily by doing this.

2) Switch off the main breaker, and then back on again. Loose internal guts of the main might be a culprit.

One more thing to look for: When the power is out, look at the meter. Is it turning or not? A stopped meter indicates the problem is before it.

Billy_Bob 02-14-2010 05:01 PM

Main electrical connections are in a world of their own. They need to be "torqued" with a torque wrench to a certain "tightness" per the label on the breaker panel, meter box, etc.

Be *sure* they retorque all your main electrical connections.

BTW - This is done with a "torque wrench" like would be used for automotive work.

And NOT a DIY thing to do. Power is ALWAYS live at main panels even with the main breaker off! (This note is for other people reading this, I know you are calling the electric company/electrician.)

Ehelper 02-14-2010 05:01 PM

Thanks. I agree, it seems to be a supply side thing. There's one transformer for the street, none of the other neighbors have reported problems. Will advise tennants to call POCO next time it winks out. Murphy's law is against us: "Any intermittent problem will cease to malfunction in the presence of a repairman".
We have already tried banging the meter, and re-setting all the breakers including the main, no help. It is frustrating, the POCO says their end is OK, the electrician says everything from the meter is OK, yet the 110 circuits wink out about every night. Somebody is missing something, and I sure don't want to mess with any mains. I may be dumb, but I'm not stupid. :)

nap 02-14-2010 05:28 PM

check out this thread:

if the electrician did not pull the meter, it could be similar to the situation I described in that thread that I had experienced.

Something like that is one of the things kb would have you whacking on the meter for.

AllanJ 02-14-2010 08:30 PM

If you take the cover off of the main panel, can you see the big lugs that hold the fat service entrance wires to the main breaker?

You need to have someone very experienced with working with electricity meaure the voltage from these lugs to neutral.

This test will distinguish between a problem upstream of the panel (such as in the cables coming from the utility pole) and a problem in your panel (such as the main breaker having a loose connection to the bus bars underneath it).

Ehelper 02-14-2010 09:50 PM

Thanks AlanJ. I appreciate your reply. What drives me crazy is this is an intermittent problem. I used my VOM and checked the voltage to the main breaker and both sides were good to ground and hot. At that time all circuits in the house were up and running. The problem seems to happen overnight. I really wished I could be there to test when it winks out, but I have no such luxury. (I wish). The panel looks clean, I checked all lugs they are tight. So it's either a bad contact on 1/2 half of the main breaker (how often does that happen?) or the POCO has a bad connnector splice on the mains on the pole, or a bad meter? note: P.S. We have had snow, downed lines, popped transformers, power surges, Also, I killed the main breaker and checked the bus connections they are good.
Thanks to all for your replies.

plummen 02-14-2010 09:57 PM

if he has an overhead electrical service check to make sure its not rubbing on a tree branch between pole and house,many times if wind blows just right branches will rub through or pull on wires. :)

kbsparky 02-14-2010 10:06 PM

Again, a simple thing to do is look at the meter when this is acting up. If it grinds to a complete halt, the problem in on the supply (POCO) end.

If this is the case, one way to get `em to fix it fast is to tell them that the power is out, and the meter has stopped completely, while other lights are still working.

The potential loss of revenue is usually enough to get them off their duffs and fix it fast! :whistling2:

AllanJ 02-14-2010 10:10 PM

I didn't know the meter stopped if one of the hot lines went bad. This would be no different than a properly functioning system where nobody was using electricity on one of the two legs.

Turn on a heavy current 240 volt appliance (such as the stove or the clothes dryer), wait a few minutes, and then feel the main breaker (from the outside). Unusual warmth would indicate a loose connection in or under it.

Ehelper 02-14-2010 10:23 PM

No trees between pole and house. Less than 100' overhead feed. Good point, many thanks.

AllanJ 02-15-2010 07:14 AM

This method is reserved for persons who are both very creative and very well versed in the handling of electricity.

A little gizmo* (you make it as opposed to buy it) connected between the fat service wire above the main breaker and the hot terminal of any breaker down below on the leg in question will strongly suggest whether your main breaker is at fault. Leave it there for a few nights.

* A one-half amp fuse (the little cylindrical kind about an inch long and 1/4 inch in diameter) in series with a 10 ohm 10 watt resistor. If the fuse blows that meant that the main breaker has failed and then enough current bypassed it through the gizmo to blow the little fuse. Requires around 1000 watts of total power usage on the leg in question. The resistor makes the gizmo not the path of least resistance and therefore not share the load and blow its fuse when the main breaker has not failed.

Ehelper 02-15-2010 08:17 PM

Thanks AlanJ!
I was wondering how to test this, your idea would work well. I was thinking if I had 2 hobbs hour meters I could put one on each leg, but I don't have them. I stopped by the house today and counted 5 pairs of splices along the 60' service drop (not counting the service tap) so it's really looking like a POCO issue. I hope they will run a new drop. I hope they don't just get out, measure the meter juice, say everythings OK and take off like they did the first time. Wish me luck! Thanks to all.

All times are GMT -5. The time now is 06:29 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1