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#47749 - 01/25/05 08:50 PM Flickering Lights
trollog Offline

Registered: 10/02/04
Posts: 273
Loc: San Diego California USA
Anyone have any ideas what might cause lights in a house to flicker. Here is the situation- reidential remodel, 200 amp service for ~1800 square foot house. Periodically throughout the day every light that is on, on any circuit in the house will flicker once, similar to the way lights flicker when a large compressor or other piece of machinery is kicking over from a dead stop. These flicker pulses are about 10-15 mins apart, occur night and day even when no machinery is running and the only thing on are the lights. The house is not inhabited at the moment and I have observed this in the evenings after everyone has gone home and nothing was plugged or drawing any power but the lights. It is not specific to any one circuit in the house, but can be observed on any light that is turned on. I have checked the panel and everything is tight and connected. Could it be a problem with the nieghborhood power? maybe a transformer going bad or something else on the POCO side of things?

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#47750 - 01/25/05 10:41 PM Re: Flickering Lights
DougW Offline

Registered: 06/08/03
Posts: 1083
Loc: North Chicago, IL
Not sure - a little outside my expertise.

Maybe somebody else on the same side of the POCO xformer has a big draw item, like a compressor or some such, and the draw is showing up as the flickler you describe.

I remember seeing another post about something like this - IIRC, the result was a grounded conductor being loose at the xformer...

#47751 - 01/26/05 02:00 AM Re: Flickering Lights
marcspages Offline

Registered: 10/15/04
Posts: 49
Loc: London, UK

I know your connections are not quite what we have in the UK, but....

this type of thing is something people write to me plenty about and it often turns out to be a water pumping/boosting station in the nearby vicinity (one case was a cellphone mast airconditioner at the end of a rural line!).

You may need the PoCo to do a monitor of the current at the feed side of the line?


#47752 - 01/26/05 02:34 AM Re: Flickering Lights
Steve Miller Offline

Registered: 08/30/01
Posts: 322
Loc: Loudoun Cty, VA
Assuming everything is tight in your eqpt it's probably the xfmr on the pole/pad. Generally the utility has several (or even many) houses on one xfmr. The other buildings could be causing it or the connections on the utility side could be in need of checking. Around here it costs nothing to have the utility come by and check their connections so I start with that.

#47753 - 01/26/05 07:31 AM Re: Flickering Lights
CTwireman Offline

Registered: 02/07/02
Posts: 839
Loc: Connecticut, USA

The way you desribe it, the lights sound like they are actually dimming, rather than flickering.

I think it's important to distinguish between "flickering" and "dimming" because the suggest very different things. Flickering suggests a loose connection, while dimming suggest a heavy load coming on (like the compressor example you gave.)

Peter D.

#47754 - 01/26/05 08:20 AM Re: Flickering Lights
Trumpy Offline


Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
Is it an Overhead service?.
Have you figured a part broken neutral into the equation?.
Or a bad joint in the service?.
It needn't be in thge PoCo gear at all, wires can break at mid-span, if the conditions are prevailently windy near the site.
Just my $0.02 worth.
Let's face it, these days if you're not young, you're old - Red Green grin

#47755 - 01/26/05 03:07 PM Re: Flickering Lights
Dnkldorf Offline

Registered: 12/12/04
Posts: 1091
Loc: nowhere usa
I'm with Trumpy on this one, and have seen this many times.

I'd go after a loose Nuetral tap, if it is an overhead service,check there to see if it is a "bug" or crimp. Then check the meter can and then into the panel.

Underground, check the meter can and the panel for tight connections.

I have also seen on overhead services, the "nuetral" wire was tight at the "bug" on the house, but turned out to be loose on the POCO's ariel lines.

Good luck....


#47756 - 01/26/05 07:25 PM Re: Flickering Lights
trollog Offline

Registered: 10/02/04
Posts: 273
Loc: San Diego California USA
It is an overhead service that we (along with the help of SDG&E ) converted to underground. The nearest xformers are 3 poles away in either direction. The UG part is new & unbroken wire, which rules out a loose "bug". My spidey sense was telling me that is was on SDG&E's end and everyone's posts just reinforce my suspicion. Thanks for all the great input!

#47757 - 01/26/05 07:29 PM Re: Flickering Lights
trollog Offline

Registered: 10/02/04
Posts: 273
Loc: San Diego California USA
And by the way, dimming is a better description of the problem than "flicker". Although it might appear as a true flicker to someone with the hopped-up senses of a hummingbird or housefly, to normal humans, I guess dimming hits the mark closer than flickering

#47758 - 01/28/05 06:23 PM Re: Flickering Lights
Attic Rat Offline

Registered: 12/14/03
Posts: 530
Loc: Bergen Co.,N.J. USA
... This probably doesn't answer your question,but I once had a troubleshooting call for flickering lights,and after literally racking my brain trying to find out what was causing it,found it to be an ordinary ink-jet printer,..that as the toner heaters were cycling on and off,... thus went the flickering,...I timed it down to the seconds.. every 24 seconds on the nose.. I unplugged it and the phenomenemenen stopped.. fancy that!! It was hard telling the H.O. that her annoying,flickering lights were caused by a puny printer...
.."if it ain't fixed,don't break a Licensed Electrician"

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