# Losing one leg of power



## devo9er

Strange problem here. Hang with me.

I got home last night and half my lights don't work. Before I went to check the main panel, I had a good feeling we lost one leg coming into the house. I pulled the panel cover off and got my meter out. I checked the main lugs before the main breaker and confirmed my prediction. 120v on one line 0v on the other. 

Now onto the weird part. My wife is going around the house trying to figure out what works/doesn't, make sure the fridge is working etc.. It's hot in my house, probably because the AC hasn't been on (it's 220v obviously). She doesn't know this and turns the temp down on the thermostat. Power comes back on completely right when she tries the AC. ?!?! I chalked it up to coincidence at first. I turned the AC back off so I could go look into other stuff. About 10 minutes later, power goes out again. I think, okay now the test, go try the AC again. Again the power comes back on....??? I turned the AC back off and the next time it took about an hour to do the same thing...

This has to be a transformer problem right? I mean I'm checking voltage at the mains. It's like when load is put on the transformer it starts working again?!?! It was night time so I haven't been able to check with the neighbors yet. 

Just wanted to get some input before I call the utilities..

Thanks and Happy Father's Day :thumbsup:


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## biggles

keep in mond away from the compressor runing when it is shut off abruptly the pressures need to somewhat equalize before another start if the compressor quick cycles it will trip the overload within or the CB..was that the lost leg coming and going at the house panel:huh:


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## devo9er

I'm sorry I don't follow. There are no tripped breakers, I'm losing an entire leg coming into the main panel. However when the AC tries to cycle on, it's bringing back the lost leg. It's as if the transformer feeding the house is tripping off and then the draw from the AC on that leg is somehow "bringing it back online". Sometimes for a few minutes, or in the case of this time, about 4 hrs.


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## joed

You have lost side of your feed from the POCO. When the AC or any 240 device comes on it will back feed the good power to the dead side of your panel.
You should turn off ALL double pole breakers in your panel until you get his fixed.


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## devo9er

I thought of this as well. However the power would remain on for a period of time after I would turn the AC back off. No other 240 devices were running. I could see that a range could back feed power but the AC compressor pump?


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## devo9er

I just flipped off all my 240 breakers and I still have full power. Perhaps the problem has been remedied outside of my home.

All though a good point, one other piece of evidence that doesn't support the back feed idea is that when the power came back on after turning the AC on, I checked power at the main lugs in the box and got 238 volts. If it were back feeding I would still only see 120. 

Hmmm!?

I'm convinced its a problem on the pole or at the distribution box. I'm in a condo so there is only so much I can check.


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## darren

Could be a loose connection somewhere, either in your panel, the meter, the distrubution panel. Ask your neighbours if they are having the same problem, if not then the problem is between the point of distrubution and your panel. If your neighbours are having the same problem, there is something wrong at the distrubtion panel or somewhere before it.


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## AllanJ

Workmen must have been restoring the power while you were playing with the air conditioner.

And sometimes the workmen may turn it off and on a few times a few times or a heavy load just when the power is turned back on might trip it off again.


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## joed

Intermittent connection can cause this. If the connection is loose it could have temporarily welded itself back together.


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## Missouri Bound

Just call the utility. You don't need to know anything other than you have only one leg hot. But keep the dbl. pole breakers off until you get it fixed. More than likely you have a loose connection or a wire which works intermittently. I had a similar problem with my service many years ago. It was an overhead service, and a strong wind would take out a leg from time to time. The POCO replaced the wires from the pole to the weatherhead and I never had another problem.


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## brightjh01

I just had that problem here. But this time of year it was the gas furnace(ele blower). Called Utility company,after a few day of aways coming on right before them got here. It stayed off, He Check the line from pole (old neighborhood), He replace crimps. We had old aluminum crimps and copper wire. fixed the problem.:smile:


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## dmxtothemax

I would call the utility company,
if it was a deliberate outage they will know,
if not then they should investigate it ?


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