Losing 1 leg of power......

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doechsli

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A few months back I posted about an electrical oddity where I was losing one leg of power in the house. It would either go off and come back on almost instantly or it would go off and stay off for maybe 10 minutes. Then come back on and be fine for long periods of time. The last failure was back in November and I reset the main breaker a couple of times and the power came back on. It has be fine since then.....until this past weekend. The same leg failed and stayed off once again for about 10 minutes. At the advice of an electrician who inspected my breaker box after the last failure I called the power company and unfortunately the power came back on before they arrived. They did pull the meter and test voltages and shake the outside drop to see if that had any impact.....it did not. Things I have noticed are;

1. Resetting the main breaker seems to "almost" make the power come back on. I can hear appliances "click".
2. The problem seems to happen more frequently on weekends when there is a heavier load.
3. When the power fails, it is solid.....never flashing....on/off.
4. I have talked to neighbors sharing the same transformer and they have not had the problem.

I really hate to keep paying an electrician $100 come out and tell me "I don't see anything". My best guess at this point is the main breaker. Any guesses?
 
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Did they check you connections at the pole or just shake the wires? The shaking might have even helped by working the loose connection and cleaning it a bit.
 
My question is did you try the things that were mentioned in your original post? In particular what I posted about checking the breaker when the power fails.
 
I would agree if resetting the breaker fixes it the power company says no problem with the feed in. I would change out the breaker.
 
I wouldn't just arbitrarily change the main. It's easy to check, as I noted how on his original post. Mains aren't cheap plus the meter will need to be pulled to change it out. Figure out the problem first. It's better to be sure it's fixed rather than just hope it's fixed.
 
I agree, based on what he’s told us what else could it be?
 
I know what you're saying bud, but it's a very simple check when it happens. It could be a bad thermal in the main breaker or it could be a loose connection at the line side lug on the main.
Thing is that you have someone explaining what they think is happening, but they don't really know. If it was an inexpensive branch breaker, I'd say sure...change it out. Worst case, you'd have a spare. A new main will likely have to have the meter pulled and an electrician, plus the cost of the main. That adds up quickly.
 
Like your post is asking, our answers would just be a guess. If it where me I'd start by removing all breakers and inspect the bars. Then tighten all connections and probe the panel when you lose power. How are your sure your dropping a leg?
 
Would you suggest an amatour play with a multi meter to the if there is power on both legs when it is out? I would but I'm not sure I want to tell someone else to do it.
 
Sure, if they're careful. It's almost a necessity given that he had qualified people check it out but found nothing. It's intermittent, so, that's when it needs to be checked. You're not going to have an electrician on standby and unless you just want to change out some parts...not many other options. Hiring a pro is usually best but he did, and still has the issue.
 
Years ago took the family to my brother-inlaws for x-mas dinner and when I got in the house I asked where he was, he was working on getting a breaker working as the lights in the bedrooms weren't working. So nosey as I am, I went and found 2 brother-laws with there head in the box. Yup they found that the contacts were ruster and had cleaned them and just before I walked away I noticed he was smearing something on the contacts, so I asked what that was and the answer was grease. I replied grease is an insulator. I got a sharp reply, all big starter relays for big equipment are in an a oil bath.
I knew that that was there for a spark arrestor but decided, what the hell and went back to visiting. Thery came upstairs, saying things like it should have worked. Two weeks later I asked if they ever got that figured out. Very quietly I herd, the electrition came and fixed it,. I just had to ask what the problem was. Even in a lower voice the answer came "grease on the contacts"
 
In answer to your question, by the time I called the power company and gathered my tools to test the main it came back on.

I am ready now as I have only a couple of screws on the panel and my tools out.

I am comfortable testing the legs of the main as I did this test the other day just to be sure I was getting 110 on each leg.

Thanks for the ideas.....when I get this diagnosed I'll post back.
 
Things known:
Problem intermittent.
Problem resets itself.
Problem is decisive on and off. No flicker.
Problem is not outside the house. Confirmed with power company and neighbor.
Problem is always corrected by cycling the main off then on.
Problem is only on one leg of the power and all branches of that leg.

I agree taking a measurement at the main breaker would tell all if done at the time it is off.

I don’t know all the possible causes downstream of the breaker that could cause this, but what you have to do in troubleshooting with only the information you have is to make each possibility fit the conditions of the things known.
I’m assuming the OP is sure he’s losing the full leg as he has said it a few times based around what is going on and off. If that’s true nothing loose in the rest of the box would be fixed by flipping the main off and on I wouldn’t think.
That was the only reason I suggested it had to be that. When he had the electrician out and he told him he had this problem and he couldn’t find anything and of course he couldn’t wait around for it to happen he should have taken some action or at least suggested something to change or try. He could have hooked up a chart recorder or something I guess to watch it for a week I guess. the idea of the OP checking voltage is good as he seems to be able to do that as I could as a home owner also, but what if it was an 80 year old grandma what would we suggest to her grandson that keeps getting called to come over and reset her electric.
 
When you do the tests turn off all double pole breakers in the panel. One leg can feed through a 240 volt device and give a false reading of voltage on the other leg.
 
Is he checking for 220v between legs or 110v leg to neutral?
 
I have tested 220 with both legs and 110 to each. Seems to be ok......this was done with everything operating normally. Waiting for my next outage to see what is happening when power is out.....

I am sure it's one leg as I have mapped my breaker box and amazingly every other breaker is without power. Taking the cover off and looking shows me that those breakers are supplied by same leg leg.

One minor correction. Resetting the main breaker does not ALWAYS fix the problem. However, it does make the devices on the impacted leg ATTEMPT to come back on for just a brief second. Resetting it has on a couple of occasions caused the power to be restored.
 
Did you happen to get a price on replacing it? Pulling the meter etc.
 
I have not gotten a price. The replacement of the breaker looks easy but I'm not sure about pulling that meter although the power company guy made it look easy.
 
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