ECN Forum Forums General Topics of the Trade General Discussion Area Pulsing Lights

Could also be a POCO XFMR.

From the poco:

Set our voltage recorder at the transfromer from 4/22/03 at 13:45 to 4/28/03 at 11:20.
There were several instances where the voltage went up to 125.9 volts for durations ranging from one to ten cycles.
There was one drop in voltage on 4/27/03 at 07:22 for one cycle when the voltage dipped to 110.9 volts.

Anyone have any thoughts? The source voltage was reported to be very stable, thus ruling out a bad transformer.

Even though it may still be possible to see some incandescent–lamp flickering, the usual voltage range that most US utilities and appliance manufacturers agree on is 110-127V {and appropriate multiples} at the building service entrance. It sounds like the utility is off the hook.

We had a situation recently, that sounds almost the same problem. Might help?

Service call to a Restaurant, lights dimming (flickering), equipment working Intermittently.

Service is 120/240 1 phase 3 wire

Customer called PUC, they checked their stuff said it was internal problem.
Out we go checked whole place for loose neutral, checked panel connections, took voltage readings and it was up and down like crazy at panel mains.

Ok, we figure PUC said they ok, maybe bad breaker. Order breaker, and pull meter to kill mains (so we could change main breaker).

Decided to take voltage reading at meter's line side. Low and behold one phase no voltage to ground.

Problem solved. Called PUC, they showed up while we waited and found that there was a break in one of the cables of the underground feeders.

Why the problem was not visable through test's at the main's, I cannot say but the end result by chance was fixed.

Now to try and justify the Invoice. (another question)

Hope this helps, long story but you never know, worth a check.

PS. PUC was pissed because we pulled the meter without notifying them, OH well.

CDN, the restaurant should send the power company your invoice and really give them something to complain about. I have a customer that sent their power company a bill for my work, when the power company said the problem was in the residence. The problem was a bad splice in the power company's service drop. They paid the bill.

Its metered with CTs because the sevice is 600amps, single phase.

CDN,
I was experiencing the same problem at my house with flickering lights occasionally.I checked all connections and could find nothing wrong.Used a Fluke digital to take voltage readings and everything appeared normal.Called out the PoCo. They came while I was at work,checked everything and left a note that said all was fine on their side.That evening,while outside, I noticed my neighbors lights doing the same thing.They were served by the same x-fmer. This time, when I pulled the panel cover to take readings,I used an analog meter and could see the voltage from each phase to neutral dropping to below 90 volts and then back up. Called PoCo.They came right out, pulled out their digital meter,tested and said everything is OK. I then took him inside to the panel where he could observe the analog meter.After seeing this, he decided to check his connections. They found the neutral lug burnt up on the pole mounted X-fmer.Problem solved.
Since then, I never use a digital for troubleshooting this kind of problem.

"They found the neutral lug burnt up on the pole mounted X-fmer.Problem solved."

We found the same problem at a residence. It required serveral days of argueing with the PoCo before they would accept that they did indeed have a problem.

GJ

Unfortunately for me I think the POCO is off the hook. The voltage on their side is stable. The customer has not reported any trouble during the past week, but I am not confident the problem is solved.

Has anyone ever seen a faulty flourescent ballast cause incandescent lights to pulse? I am trying to pinpoint possiblities to this intermittnet problem. I feel like I am chasing a ghost. Maybe I am!!

spyder, I'm sure this is not news to you, but intermittent electrical problems can certainly be the most frustrating.

I would guess that unless a defective fluorescent fixture was actually causing reduced line voltage, that it would not affect other lighting.