Lights Flickering

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richmacary

Member
I have an issue with lights flickering. The local utility checked the line to the main and replaced it. I have 2 - 200 amp main disconnects outside the house with to 2 - breaker panel boxes in the garage.

A volt meter checking one boxes shows 124 volts when testing from neutral to each leg. The same test performed on the other box shows 133 volts on one leg and 115 volts on the other. How can this be? I also noticed about 9 volts when testing from neutral to any metal surface in the box.
Any ideas?
 
charlie

charlie

Senior Member
Location
Indianapolis
Re: Lights Flickering

Get an electrician. You have an open neutral or a bad connection from the first panelboard to the second panelboard and it needs to be replaced or repaired. :D
 
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thomasbp

New member
Re: Lights Flickering

I experienced flickering lights in a rented house, and found the cause to be a loose neutral bar and loose individal lugs.
 
bob

bob

Senior Member
Location
Alabama
Re: Lights Flickering

Rich
Charlie is right on the mark for a change. :D :D :D
Do it quickly or you will smoke every thing in the house. If the neutral opens completely you will apply 240 volts to all of your 120 volt possessions.
 
E

Ed MacLaren

Senior Member
Re: Lights Flickering

If the neutral opens completely you will apply 240 volts to all of your 120 volt possessions.
Click to expand...
Yes, but not the full 240 volts, and not all loads will get the damaging overvoltage.

The simplified sketch below shows that the complete loss of the neutral in any 3-wire circuit results in the loads being in series across the 240 volts.

Ed

3wire3.gif
 
George Stolz

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
Re: Lights Flickering

Isn't the undervoltage damaging too?

I've recently seen a branch circuit at 60V due to an open neutral, and it appeared to destroy some fancy (LCD display) phones.
 
bob

bob

Senior Member
Location
Alabama
Re: Lights Flickering

George
It may be possible but most of the damage is hi voltage. Low voltage will affect a computer hard drive motor and some electronics will not act properly. Maybe someone else can add more examples.
 
M

mc5w

Senior Member
Re: Lights Flickering

I have also seen instances where only 1/4 or 1/3 of the wire strands are conducting in an old service or feeder that was wired using copper. This is about equivalent to old steel water pipes that are clogged with iron bacteria.

The voltage regulation is not bad until they go to run and air compressor or arc welder.

I have also seen an instance of a 200 amp copper wired service that burned up with only 20 amps of load on it. The culprit was old age and accumulated copper oxide that reduced the wire capacity to 10 or 15 amps.
 
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richmacary

Member
Re: Lights Flickering

Hey guys, sorry it's taken me so long to reply on what was found with the lights flickering issue.

As Charlie, Bob and others had stated, a local electrical contractor found the problem at the first panel box on the neutral bus between the primary lug and the bar. It had literally fried the connection. Unfortunately, I smoked a VCR and ceiling fan along the way but thank God no other damage.

Thank to all for your timely suggestions except for Chongs suggestion to buy a new house. :p
 
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