Drop in outlet voltage when overhead lights turned on


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Old 05-26-19, 11:33 AM
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Drop in outlet voltage when overhead lights turned on

Was checking outlets with a multimeter. All read 119-120. When I turn on a bedroom overhead light, I get a drop of about 15 volts in a bunch of outlets. Then another 15 volt drop from the other bedroom light. So around 91-92 reading in outlets when both lights are on.

Is this normal? I canít run an air compressor in these outlets when these two lights are on for example.
 
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Old 05-26-19, 12:09 PM
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No.... that is not normal and you can't run anything there at all.

Have you checked the voltage at the panel to make sure there is no problem on the incoming side ?
If that is all ok..... there is a problem in that circuit. Typically if it's a bad/loose connection.... the voltage will fluctuate. You're saying the voltage drops a fixed amount. That sounds more like a miswired circuit.
 
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Old 05-26-19, 12:24 PM
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What happened that caused you to measure voltage at the outlets? Did you change something?
 
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Old 05-26-19, 12:32 PM
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Thx for the replies. Just bought this place so nothing I know of happened. I noticed it when I ran my air compressor in those rooms. Wasnít running full power. So checked outlets
 
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Old 05-26-19, 01:13 PM
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While some voltage drop is normal when a load is added to a circuit, a 15-volt drop when just turning on some lights is not. I would start by turning off any two pole breakers at the electrical panel and see if anything changes. I'm suspecting you have a bad leg on your electrical service.
 
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Old 05-26-19, 01:59 PM
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What I donít understand is the lights are on breaker 2, but the outlets on breaker 11 (kitchen) have the exact same voltage drop
 
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Old 05-26-19, 02:10 PM
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Also - Iím obviously no pro. How do I do these checks at the panel, and safely obviously? I have a multimeter and non contact voltage detector
 
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Old 05-26-19, 03:54 PM
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Did you measure the voltage on the lights? If it is high then you have a loose neutral on your service feeder.
 
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Old 05-26-19, 04:26 PM
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What I don’t understand is the lights are on breaker 2, but the outlets on breaker 11
Also an indication of a bad leg. Did you turn off the 2 pole breakers like I mentioned in my earlier post and see if anything changed?

Turn off the main breaker of the panel and carefully remove the cover. The big lines feeding the main breaker will still be hot. With the main still off, measure the voltage between each leg. You should get 240 volts. Then measure between each leg and neutral. You should get 120 volts.

If any of the above is not correct you need to call the power companies 24 hour help line and tell them you have a bad leg.
 
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Old 05-26-19, 04:30 PM
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What did you use as reference to measure outlet voltage, neutral or ground. You should use neutral. Could be loose screws in you breaker panel. Take a screwdriver with an insulated handle and wrap electrical tape from the handle to 1 inch of the tip. With good lighting and holding the screwdriver with a glove tighten the connection screws (breakers, neutral bus, ground bus, meter feeds). If there are any wire nuts make sure they are tight and pull gently on insulation of one wire to see if it comes loose from the wire nut. Be careful and report back if any change.
 
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Old 05-27-19, 07:46 AM
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Wrap the screwdriver shaft with tape down to 3/16 inch of the tip.

Flip off each breaker before touching the screw(s) on it.

If a screw seems tight, loosen it a quqrter turn and retighten it which helps clean and improve the connection.

Do not use tremendous stupendous force when tightening.
 
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Old 05-27-19, 08:26 AM
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Loose neutral somewhere. Possibly in the service, but need more info, pics. If not, then in a J-box in the circuit. Prob behind a feed thu receptacle. (Pigtail tjosebif you find them). Divide and conquer. Likely not a utility problem. If you lost a phase the difference would be greater and would vary as 240 volt loads turned on and off (WH, heaters, oven)
 
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Old 05-27-19, 09:07 AM
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While you have the light turned on and the voltage at 95 at a few receptacles, are there any other receptacles with the voltage close to 120? Are there any receptacles with voltage actually well above 120? (Do not use or test with a hair dryer or iron or other high wattage appliance at this time.)

Flip off breakers for water heater, stove, air conditioner, heat, dryer, oven, and also breakers with two handles tied together. Go back and measure the voltage at the various receptacles.
 
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Old 05-27-19, 11:09 AM
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Yes, with the overhead lights on the outlets are fine on the living room circuit.

Power company is checking now. Figured it canít hurt anyway and they owe me some service when I went without power for a week a few years ago.

Will report back. Iíll probably get an electrician but Iím really curious what the problem is.
 
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Old 05-27-19, 12:53 PM
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Well I have a new power line now but that didnít do the trick.

As Iím troubleshooting Iím trying to think back if anything odd happened. I had an overhead light go out in the living room. Itís on breaker 5. I changed the bulb a while but nothing. I opened it up just now and the wires look in rough shape. I have 3 neutral wires and 1 hot wire connected to the fixture. The fixture looks burnt. I can post a pic later since I canít on my phone apparently.

Is there any way this could affect the outlets going to breaker 2, 7 and 11 in this house though? The outlets to breaker 13 are fine. Just measured at 119. All the others are 94.8 exactly.

Also, how do I measure overhead light with a multimeter?

Im decent with house stuff but donít know much about electrical obviously.

I will probably call an electrician but again, Iím really curious at this point.

Thanks again for everyone taking their time to pass on a little knowledge. Though Iím an amateur i know wat more about electrical than I did just a month ago.
 
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Old 05-27-19, 02:46 PM
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Yes...... if there are three neutral wires there..... it could definitely effect the receptacles.
There wold have to be at least two black wires in a splice.

Depending on the OS.... some phones can post a picture directly. If you can't..... follow this.
How-to-insert-pictures.
 
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Old 05-27-19, 02:53 PM
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Have you measured the voltages at the breaker? Measure all the breakers and see how many are not correct.
 
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Old 05-27-19, 07:34 PM
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Spoke with someone whoís a pro at this stuff and he suggested tightening all the neutrals at the box too. Will try tomorrow with the insulated screwdriver.
 
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Old 05-27-19, 09:15 PM
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Turn off ALL two-pole breakers. Then see whatís going on. If it is a lost phase problem everything on A or B phase will be out. Otherwise youíve got a loose neut somewhere. Prob in a receptacle that is burnt up in back.
 
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Old 05-27-19, 09:56 PM
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If it is a loose neutral then you should get a proper voltage reading to ground.
 
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Old 05-28-19, 01:40 PM
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I think this issue has run its course. Same questions are being asked 2-3 times. OP has answered some and yet to answer others. Time to call an electrician. Good luck.
 
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Old 05-31-19, 11:45 AM
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lol "Beezlebob" has anointed himself ruler of the thread.

Problem solved. Loose neutral at the panel indeed.

Back to 120 in all outlets now even with those lights on.
 
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Old 06-01-19, 06:00 AM
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OP tightening the neutral bus was suggested in post 10. Did you read it?
 
 

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