Help With Flickering Lights


  #1  
Old 08-20-03, 08:00 PM
Jeff.Roey
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Question Help With Flickering Lights

Folks,

I've been in my current house for 18 months and since I moved in I've noticed any major appliance starting up causes the lights to dim for flicker momentarily. This includes starting applicances as large as the central A/C and electric dryer and as small as turning on the TV or the fridge cycling on.

Up to recently I thought it was a start-up draw associated with the appliance but the more I look into this, the more I realize I shouldn't be experiencing the flicker. Service is a relatively new 200A (installed in '94).

I'm looking for suggestions on how and where to begin troublshooting th culprit. Any help you can provide is much appreciated.

Thanks,

Jeff
 
  #2  
Old 08-20-03, 08:10 PM
J
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If you search back on this forum for the keyword "dimming", you'll find a lot of information on this topic.

Yes, it is the startup draw of these major appliances that is causing the dim. But this is working in conjunction with something else that is wrong. The two most common causes are (1) a loose connection in your panel or in the power company's equipment, or (2) an undersize wire or transformer on the power company's side. Sometimes when the service is upgraded in an older house, sometimes the power company's equipment can't keep pace (even though they often try to avoid making upgrades to save a few bucks).

Start by calling your power company. Ask them to investigate it from their side. Most of the time, they can fix this. But if they report that all is okay on their side, then ask an electrician to check the connections in your panel.
 
  #3  
Old 08-21-03, 07:52 AM
P
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I suggest a "dynamic" voltage test--this means testing for voltage with a "load" on the system. If there is a defective connection with a resistance of 3 Ohms, the voltage- drop with a load current of 2 amps = 6vollts. With a load-current of 30 amps the V.-D. = 90 volts.

You'll need a volt-meter that will indicate a numerical value, i.e., "109" volts. Test across the terminals of 2 adjacent circuit-breakers-you should read 220 volts (approx). Next, test between the Neutral terminal bar where the White wires connect and the terminals of the two adjacent CB's. Both readings should be 110 volts (approx).------------------Good Luck!!!!!!!!!!
 
  #4  
Old 08-21-03, 12:17 PM
Jeff.Roey
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Thanks for the input.

John,

I took your advice and did a bit of reading about dimming in this forum. A lot of good info here. Based on one of the other threads I went ahead and checked the mains prior to the circuit breakers. The results are as folows:

Steady voltage on the mains prior to the breakers were measured at 119.2 and 121.8 volts. At A/C startup, the voltage dipped (before the breakers) to 113.8 and 114.0 volts respectively. I went ahead and put a call into the power company and expect to see them today.

Pat,

I'll go ahead and conduct a dynmic test as you described. I do have a voltmeter that indicates actual measurements but I'm a bit unclear on what I should be looking for.

You suggest I test two adjacent breakers (I'm assuming adjacent vertically?) and looking for 220ish. Then I'm checking each breaker to neutral for 110ish. Is the objective to find something less than 110 and begin to look here for a loose neutral, etc?

Again, thanks for the help and I'll let you know how I make out.

Jeff
 
 

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