Light Flicker

benleef

I know this question may be presented often and I've done much research trying to diagnose the problem, but have been unable to figure it out, or determine whether it is something I should be concerned with.

I've noticed that when my GAS dryer kicks on, a few select lights will quickly dim. It only occurs right when the dryer kicks on. There are three lights that I've been able to see exhibit the behavior.

1) chandelier in dining room on dimmer (circuit 1)
2) boob light in kitchen on dimmer (circuit 2)
3) outdoor flood light (circuit 3--same circuit as dryer and this circuit may be a little overloaded--at least has dryer, washer, gas stove, flood light)

I've done some meter tests and everything seems to be fine from main to main, main to neutral, and from each of the circuits to neutral. I also tested the dryer on a different circuit with it being the only thing on the circuit.

I've ran tests from circuit to neutral while simultaneously turning on the dryer and the voltage drops from 124 to 121 very quickly and then jumps back up.

Anyone think this is a serious issue, further diagnostics I could do, or any thoughts?

Thanks!

fltdek

WHAT? Tell us what size the breaker (circuit 3) is? I would find it hard to believe that all of that is on a single circuit. You would be having more issues than just flickering lights....

benleef

Sorry--not electric oven and stove. It is gas, so it's basically just the ignitor.

fa_f3_20

Was the washer running when you did these tests? The circuit may have been a bit heavily loaded. Standard practice for new construction these days is to put the washer on its own circuit. In fact, I think the 2008 NEC requires it.

The things that you observed on the other circuits may be the result of the dryer motor putting harmonics on the line while it is starting. Non-sinusoidal waveforms on the incoming power can confuse dimmers. It's probably OK, although it might be an indication that the motor's start capacitor is failing, if it has one.

benleef

Thanks for the reply. Yeah I found it peculiar that it was lights on dimmers affected (aside from the flood light on the same circuit).

The washer was not on when running test or necessarily when lights flicker. I'm going to put the washer on separate circuit definitely.

The dryer is only one year old so I hope it's not going bad, but I did buy extended warranty on it.

Is this problem something I should worry about as far as safety, harm to other appliances?

fa_f3_20

Ben, I don't think it's anything you need to worry about, unless it gets a lot worse. Some motors will draw surprising amounts of current for a fraction of a second while they start. As long as the circuit is protected properly, and there's no loose connections anywhere, it's OK.

benleef

Thanks! I checked all the connections on the neutral bar and tightened some of the looser ones. Soon I'll put the washer on its own circuit and just keep an eye on things to see if it gets worse. Thanks again for the reply.

fltdek

My next door neighbors lights dim briefly when their new HVAC system kicks on. Annoying, but thats the way it is..

bbo

weird, my neighbors lights dim when i start up my air compessors ...

fltdek

HaHa! Thats your neighbors wife, dimming the lights so she can watch you work.....she must like a man with a tool belt...lol