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Lights dimming randomly in my house

71K views 26 replies 16 participants last post by  jbfan 
#1 ·
I am having a problem with dimming/brightening lights in every room of my house for the last couple of weeks. I checked the wires coming in the panel and one hot wire that goes to main breaker was loose so I tightened it down but I am still having the same problem. I have searched google and it sound like that it is a open neutral. I changed bathroom vent fan shortly before dimming started. Fan has copper stranded conductors connected to Romex solid conductors. Do you think that this is the problem?
 
#2 ·
NO. This is your service neutral causing the problem. I can't believe no one has told you to call the POCO (power company).

DO IT IMMEDIATELY! Have them come ASAP!
You should NOT have waited so long!

If you checked the lines at the main breaker you did ALL you can do. The POCO will check the connections at the meter pan, top of the riser and at the pole.
 
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#4 ·
There is a problem somewhere between the pole outside and the main panel. You need to find it.

The whole house is affected. The problem is NOT in the bath fan.
 
#7 ·
Listen.

LISTEN!

I am not an alarmist, and I seldom use phrases like "burn your house down", but this is a genuine emergency. This is nothing to fool around with. Peter has tried to give you a subtle warning to solve this ASAP.

A loose netural causes dimming on one phase, and brightening on the other. This "brighter" phase is actually receiving a higher voltage. As this problem worsens, light bulbs will explode and your electronics can spontaneously go ablaze. No kidding.

That said, put in another trouble call to the power company for a suspected loose neutral. Call an electrician!

This is nothing to fool around with. If you choose not to take my warning seriuosly, please PM the site administrator with the name of your favorite charity so that we can send memorial contributions upon your death.
 
#8 ·
It's not that I don't take your warning seriously, I just thought that I could save some money but doing it myself. I had an electrician come out tonight and he said that the neutral between the meter and the disconnect in the basement was faulty. He will come back Monday to give me an estimate. Thanks for your concern and advice.
 
#11 ·
HomeRepairNoob. The others have alread said what needs to be said, but this is real and I feel compelled to not only agree with them, but also suggest you hasten a fix.

First, You are risking loosing your computer by using it right now. Dont just turn it off, unplug it. Then unplug all your electronics..
Next unplug the fridge and only open it when needed to keep the food cold.

Call a real electrician.. A good one would not have put the fix off till monday. I know this will cost, but this one time it is worth it.

If you must survive the night under these conditions get out the candles. Turn off all the single pole breakers.
 
#13 ·
No, that's not why you have a dimming problem. I can say with 1000% certainty that whoever related your dimming problem to an undersized grounding electrode conductor to the water line was a complete electrical idiot.

A dimming only problem is either a loose hot wire, bad hot wire tap, overloaded utility transformer, or undersized service conductors. None of these items present a hazard. Just an inconvenience.
 
#14 ·
This is slightly OT but still relevant.

My friend was asking me about a multiwire branch circuit that his father had come across in his own house. His family room has two independent receptacle circuits and when his father found two hots and one neutral in the same box, he became confused. I explained what he was looking at and described how the neutral from the panel should be physically wired so that it can be safely disconected from one circuit w/o compromising continuity to the other. He was suprised (and somewhat skeptical) when I drew the circuit and demonstrated how his father's 120V appliances could be subjected to 240V if the neutral to the panel became disco'd. Well, seems like the lesson came a little too late...

Seems that while we were discussing the issue at work, his father went ahead and started rewiring the family room. Disconnected the neutral connection from the panel and POOF went the TV. POW went the bulbs in the table lamps. CRACKLE-POP-PLOOOP went the stereo receiver. A few other appliances bit the dust as well. His father was, er, uh, quite suprised!

Anyhoo, I cannot agree more with the others that made the cautionary posts.
 
#15 ·
Yes, indeed. A multiwire branch circuit is a smaller version of your service to your home.

This is the main reason why the code requires each netural conductor in the panel to be in a hole in the neutral bar of its own. That way, you can't accidentally disconnect a multiwire neutral when you're servicing another circuit.
 
#18 ·
I called power company out again because I noticed a bad spot on the sevice line neutral. The spot turned out to be only mold from tree above, but the guy replaced connectors at the house and utility pole and everything works fine now.:thumbup::no::thumbup: Thanks again for your help.
 
#19 ·
Its great that there has been such an evident display of concern on the part of the folks on here. It's settling that The poster showed as least the diligence to follow up with the advice of the guys that warned him. But what the hell is wrong with A. the power company and B. the electrician? The power company says at first that everything is ok on their end? Have we become so automated that the power company just checks a monitor and says there isn't a problem that people know they are experiencing. Especially a serious problem. Not, "there doesn't seem to be anything wrong with the delivery, but what you've got is a very serious issue", but just basically " well, we don't think it's our fault, good luck". Thats BS. And the electrician? "Ok, so If you still haven't burned to death by Monday, I'll come by and give you an estimate." Then what? Setup an appointment to take care of it next week?

Well, you have a blocked artery in your heart....call me next week sometime and we'll get that taken care of....

People's laxadasical attitudes put your family in jeopardy and these are the people we are supposed to trust?
 
#20 · (Edited)
I want to thank the people on this thread for teaching me about "loose neutrals" and the dangers they pose. The dimming/brightening phenomena started in our house yesterday and I found this thread with a Google search. Neither my husband nor I had considered this possibility. After I found your advice, he tested the outlets and found that many of them were running high in the 135-140+ range.

We unplugged the non-essentials in the house and I called the power company this morning. They showed up in under 2 hours and sure enough we had a loose neutral outside.

We probably would have waited longer to do something had I not stumbled on this thread, so thank you all for saving our house and appliances. The cable box may be a casualty, but that's the small stuff.

Great advice! :thumbsup:
 
#23 · (Edited)
This is not really for the do-it-yourselfer but with some electrical know-how it can be done.

Unplug everything from all circuits and turn off breakers to wired-in equipment like furnaces.

Turn off your main breaker

Take a long length of #6 bare copper wire and connect one end to the neutral bus in your main panel (Or to the outside of the panel if you know the neutral bus is secured well to the metal of the panel.)

Connect the other end to the bare support wire or ground wire ovehead connecting your house to the utility pole.

Turn on the power and plug in several incandescent lights here and there and on different circuits.

If turning the lights on and off still causes dimming and brightening of all of the rest, you have almost proved that the problem is in the power company's wires or equipment.

You can try connecting the end of the bare wire to different places including the outside of the meter box to further narrow down on the location of the problem.

If the flickering went away, chances are there is a problem in the wiring between the ends of the bare wire you string, or in your panel. You might leave the bare wire in place while you get things fixed, although in all cases you need to turn off the main breaker before disconnecting, moving, or reconnecting the bare wire.
 
#25 ·
ok guys i'm suspect of having a lose or failing neutral.some lights dim some brighten.so i started checking outlets and light fixtures and noticed a 110 to 140 difference on them.when i switch off all the breakers the voltage going into the main is even at 126 a side but as i start flipping stuff on the difference grows.ok so the three big cables coming out of the power company's meter and going into my exterior service panel are 2 120v hots and a neutral right?when i first opened the service box there was a fairly large wasp nest next to and below my neutral terminal.so today i took care of that but it didn't help the load voltage variations.when cleaning off all the wasp goo off the neutral wire i noticed that one of the wires on that splitter is going straight to ground below the service box.is that right?
 
#27 ·
It is better to start a new thread than to resurect one from 4 years ago.

What are you calling a splitter?
If it is in the service panel, then it is fine.
Did you try to tighten the wires?
If you tightened the wires, I would call the Poco to come out and check their connections.
 
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