For several weeks now, the ceiling lights in my tri-level home flicker very briefly about every ten seconds from just after 12 noon to a bit after eight p.m. This flicking problem starts and then stops like clockwork during the stated period.

Lights and other equipment plugged into a wall socket do not flicker at all.

I had an electrician come to the house a couple of days ago who said he'd never seen or heard of such a problem, and he suggested either "not worrying about it" or else calling the power company, which I haven't yet done.

I've done a lot of searching on the internet but haven't found descriptions of similar problems.

Any ideas or suggestions about what's going on here and what I should do about it would be greatly appreciated. My wife doesn't even notice the flickering, but unfortunately it's making me kind of crazy. Thank you.

 

A couple of questions while we wait for the pros.
1. What type of bulbs in that fixture. CFLs might be more sensitive to voltage fluctuations.
2. Are you in a residential area or are there any business or industries near or along your power feed. The "like clockwork" comments sometimes points to heavy machines starting up and running for 8 hours.

Bud

PS welcome to the forum

 

Bud, we have a small tri-level house of around 1400 square feet.

The ceiling lights have several types of bulbs. My bedroom office and two other bedrooms here on the third floor as well as the den ceiling lights (on the bottom floor) that flicker have CFL bulbs; the bathroom on the third floor has fist size incandescents in a five bulb lightbar; and the living room and dining room ceiling lights on the second floor are small Christmas tree like bulbs in chandaleers. All of the above ceiling lights flicker about every ten seconds during that noonish to eightish period. Interestingly (at least to me), I have charted thirteen seconds between flickers on several days; ten seconds between flickers on several days; and similar time variations, depending on different days. Very weird to me.

We live in an old (1970-ish) middle class neighborhood. There are several neighbors who work on cars in their garages (mainly on weekends) with welding equipment, etc., but none of them work a regular 12 to 8 and 7-day schedule that would account for this strange problem in my home. The only industrial-sized industry is about two miles away -- a large chemical plant.

And thank you for your welcome to the forum.

Chet

 

In addition to Bud's questions, do you have any other appliances that follow a daily schedule, like a water heater timer or demand meter, pool pump, pool heater or spa?

Did the electrician do any tests or inspections while there? If so, do you know what he checked?

I agree that you should call the power company as it is reasonable this is a power quality disturbance coming from outside.

 

I'd thought about the daily schedule appliances, and the answer to that is "Nope. We don't have any."

The electrician didn't do much when he was here other than to stare with me at each of the ceiling lights throughout the house to notice the pulse-like behavior of the flicker at the (on that day) thirteen second interval. He did open the fuse box (you can tell I'm an old man by this phrasing I bet) but didn't do anything with it other than to ask if any of the breakers had tripped? Answer: We've been in this house for seventeen years and have had a breaker trip once several years ago.

He went into the crawl space and said the wiring from outside into the fuse box looked fine. He did say I could open the fuse box and tighten any wires but that he didn't think that was the problem. I told him I was too old and ignorant to be farting around with electrical wires. He smiled and didn't offer to do any tightening himself, which I took to mean the chances of that being the source of the problem was slim and none. That's also about the time when he suggested calling the power company while "not worrying about it" in the meantime.

Thank you for helping me.

Chet

 

I agree that is it probably not a loose connection given the unusual correlation to time. A loose connection would be around-the-clock and would probably be worse when you had a large electric appliance turned on (water heater, stove, oven, etc) or when the weather was windy.

Hopefully the power company will put a data logger on the line for 24h and capture the anomaly.

 

If the related bulbs that are flickering are cfl, you could replace them with incandescent or perhaps LED. The incandescent are known to be very stable, although more expensive to run. If you have other incandescent bulbs in the house you might be able to swap.

I'm going to just watch from the sidelines as ibpooks is far better at this than I am.

Best,
Bud

 

Have you measured the voltage constantly using your own voltmeter, notably seeing if the needle vibrates or the numeric readout goes erratic every 10 seconds etc.

Not all voltmeters will sense very short power dips or spikes so if your voltmeter does not show anything unusual, nothing is proved.

Maybe there is a high power drawing appliance or air conditioner in a neighbor's house that is malfunctioning, it tries to start but can't and a thermal safety cutoff occurs. It then cools down and tries again to start, etc.

 

Flickers on weekends? The eight hour shift timing and the large chem plant are notable.

 

A friend had a similar problem. The electric company said no problem on their side. She had her service replaced. The problem continued. She came home one day to find her street filled with electric company trucks and guys in hazmat suits in her back yard removing the dirt under the transformer that served her house.

The electric company as she finally found out had lied about the problem not being on their end. The transformer was old and failing but they had to wait to replace it till their budget permitted because it was an an environmental hazard (PCBs) and they couldn't just swap it out due to the whole area being contaminated from leakage.

Do you have dead grass around the transformer that supplies your house?

 

To old to start messing with the wiring, Hmm.
Electrition did not even check the incoming wiring with a meter, Hmm.
Last time I'd be calling him.
I 100% agree I'd start with the power company.
I have my own horror story with flickering light's that involves a house burning down but I'll save that one for now.