Power on Circuit Off then On Again

Hi:

A few weeks ago, the power on one circuit went out. The breaker was not off but I switched it on and off several times to see if that would help. It didn't. I researched it online to see if I could somehow fix it myself but thought I better call an electrician.

The next morning, however, power was miraculously back so I didn't call anyone.

2 weeks later the power went off again. This time it was off for 3 days. I was about to call someone but now I am not sure they will be able to find anything wrong because power is back.

Does anyone know what the problem could be. I am guessing it is not a problem with the local power company and that I will need to pay an electrician to check it out. I have done my own electrical work on light fixtures and changing outlets, but unless it is something similar I probably can't do it myself at this time (busy with work).

Thanks for any suggestions, Kent

A loose connection, maybe a backstab on a receptacle.
Check the entire circuit, and look for the fist nonworking, or the last working receptacle.

You have a loose wire, or corroded connection, somewhere, which is making intermittent contact. IT will be difficult to diagnose when it is working, unless you can disrupt the power by "jiggling something.

What you can do now is turn off the breaker, then test various outlets, lights, or whatever to see what all is on the circuit. (What is no longer working with the breaker off.)

Then the next time the power goes out on this circuit, see if all of these have lost power or just a few. Then that will be a clue as to where the problem is!

And verify that it is things just on this one breaker! If there are things which have stopped working from several different breakers THAT is a different problem (tell electrician).

There is probably a loose connection somewhere. And this could include wires going into the holes in the back of an outlet. (Better to use the screws on the side of an outlet as these are better connections.)

Many times wiring will go in a line from the breaker panel to each outlet/light and the furthest from the panel is the last device on the line. (But not always!)

So if you have...

Breaker panel, outlet A, outlet B, outlet C, outlet D, outlet E, outlet F.

Then power goes out and outlets D, E, and F have stopped working but A, B and C are still working, then the problem is probably a poor connection with outlets C or D.

An electrician would have advanced testing equipment which would make finding the problem easier as well as knowledge and experience which would allow him to "know just by looking" what wires probably go where.

But I guarantee that as soon as the electrician walks in the door, the problem will go away! :D (But if you know which outlets/lights stop working and can tell the electrician this, that would be a BIG help to the electrician.)

Thanks very much everyone for your suggestions. Your explanations are very clear and I understand what to look for.

I thought it was everything on one circuit that goes out but I will check to be sure and then if and when the power goes out again I will check to see if all or just some of the outlets are out. Then I will turn off the breaker and look in the back of the outlets to check for any loose connections. If I can't find anything I will call an electrician.

If it is the entire circuit that goes out then I assume the loose connection (or corrosion) could be at the circuit box. Can I safely remove the cover to look for that. I haven't worked in the box before so am a little reluctant to do that unless just looking is safe. I should turn off the Main switch at the box, right. But the wires gong into the main switch will still be live so I don't touch anything there. Am I understanding this correctly?

Thanks again. I appreciate the help.

Unless you pull the meter (something you normally aren't authorized to do), there's always power in the panel. As long as you don't drop a screwdriver, screw, or something metalic into the box, or touch the hot leads, it isn't particularly dangerous. But, a face shield and insulating gloves would offer a modicum of protection if you were really cautious. In general, it's not a big deal to remove the panel cover...just look, don't touch.

It is a loose connection somewhere. I would I.D. the circuit and start at the service panel. Look for loose wires/screws. If you can shut off the main, you can then check all the screws on the breakers and check the neutrals. As was mentioned.....be carefull, where gloves and eye protection. Everything beyond the main once it's off will be de-energized. I had an issue at one time with intermittent loss of power and it turned out to be at the meter pan. It is a 2 meter pan with both meters fed from one service. The meter just basically plugs into some clips and those clips were screwed to the contact bars with small machine screws. One clip had a screw that must have been loose from the day it was installed in 1978. The screw hole threads were junk from arcing. Me and a friend fixed it. Well actually my friend did most of the dangerous work....LIVE........He was a Union Electrician for over 35 years and mostly a job site foremen on multi million dollar construction projects......He drilled and retapped the hole and reinstalled the clip with a larger screw..... We had already done a few other things previously and fortunately the issue happened right while he was there and we were able to track it back to the meter.......The intermittent nature of the problem makes it a lot tougher to find.....

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If it is the entire circuit that goes out then I assume the loose connection (or corrosion) could be at the circuit box

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Not necessarily.

The circuit feeds through the receptacles and 7 out of 10 times it is a loose connection stabbed into in the back of a receptacle. It's WAY easier to find when the power is out.

It will be helpful to find out exactly what is on the circuit while everything is still working.

Load the circuit with a 10A hair dryer plugged into one outlet of a duplex.
A 3vac drop in voltage measured in the other outlet is reasonable, depending on the wire size, copper or alum, and distance to the load center.
For #14 copper, to get 3v/10A = 300 milliohms wire resistance, you need 58'.

This test may cause an intermittent connection to go permanently open.

Thanks everyone. I was able to check which outlets are on the same circuit and there were more there than I first thought. So I have an idea where the faulty outlet might be and I'll probably wait until it goes out again and then I will check it to see if I can find a loose connection. This is looking promising and again I would like to thank everyone for your help. I feel confident I will be able to fix this myself.

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Originally Posted by Kent10

Thanks everyone. I was able to check which outlets are on the same circuit and there were more there than I first thought. So I have an idea where the faulty outlet might be and I'll probably wait until it goes out again and then I will check it to see if I can find a loose connection. This is looking promising and again I would like to thank everyone for your help. I feel confident I will be able to fix this myself.

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A loose/corroded connection can cause a fire. I would hire an electrician who can troubleshoot the problem quickly and efficiently with the use of a DMM/AMM and Megger. Why risk it for this long when you know you have a potentially life threatening problem that needs immediate attention?

Do you have any idea how many fires are started each year from problems just like yours? Use common sense and get someone out there quickly.

Thanks for your concern, jar546. I decided to look for the problem instead of wait and I believe I have fixed it. I looked inside the first outlet in the group that wasn't working and sure enough one of the wires was just hanging there. I secured it and all is well. I learned a lot from all of you and it makes me feel good that I could fix it myself. Thanks!