Jump to content

Bizarre Electrical Phenomenon


Recommended Posts

Something crazy and quite alarming began two days ago at our home.

In the morning begins a concert of varying and random events of low level buzz/hum that sometimes crescendos to a vibration in and around our wall on which our main electrical panel is located.

Best I can describe the noise: if you've ever heard that "bzzzzzzuuummm" that occurs when a fuse blows on the electrical lines somewhere down the road on the utility pole. It's very low frequency, like a low string on the bass guitar.

Conditions around our house and panel that might be relevant:

Service is an overhead lateral to our mast which terminates about 8' above our roof.
Panel is 125 amp
Two days ago we had a major wind storm that took out power in different parts of our area but not our house
Noise occurs only in the morning time--maybe when electrical demand in the neighborhood is high as everyone is getting out of bed. . . ?
The first morning after the wind storm, the phenomenon was constant for about 4-5 hours. It was loud enough to keep my wife and I awake.
2nd morning (today) it wasn't as long or as frequent and only in the morning
Our lights never flickered or surged.

We've been here five years and never had this before through plenty of wind storms and power outages.

My wife thought we were going to die from electrocution or our house was going to explode.

I wasn't quite as alarmed. . . but should I be?

Link to post
Share on other sites

With a digital multimeter, measure both legs of your service relative to the neutral. You can do this at the dryer outlet if you have an electric dryer. Or you can measure a variety of 120 volt outlets.

Make sure you have an equal voltage on both legs.

In any case I would call the power company and tell them you suspect a problem, storm related. It could be the transformer that supplies your house is faulty or there's a bad connection. But it could be a loose connection in your panel around the main breaker.

AC at 60 cycles per second has a low hum.

Link to post
Share on other sites

Check all appliances carefully for proper operation. Check any appliance/device in the house that may have either a motor, transformer or coil (doorbell ringer, circuit breakers, etc) in it. If you've a surge protector device anywhere, check for proper operation.

Finally, it could be low frequency harmonics that some consumer of electric power is injecting into the same distribution line that serves your house. Coils in motors, transformers are made for 60 cycle. Inject a different frequency and something will be askew. Harmonics come from non-linear loads such as solid state switching devices. I once worked on induction heating equipment that converted 400 KW or more from 480 volt 3 phase to 3,000 cycle, 800 volt single phase. Most were solid state devices and the utility would call us occasionally with issues involving harmonics from our plant.

Marc

Link to post
Share on other sites

With a digital multimeter, measure both legs of your service relative to the neutral. You can do this at the dryer outlet if you have an electric dryer. Or you can measure a variety of 120 volt outlets.

Make sure you have an equal voltage on both legs.

In any case I would call the power company and tell them you suspect a problem, storm related. It could be the transformer that supplies your house is faulty or there's a bad connection. But it could be a loose connection in your panel around the main breaker.

AC at 60 cycles per second has a low hum.

John, Just to be clear, this should be done with a decent 120-volt load turned on.

Link to post
Share on other sites

With a digital multimeter, measure both legs of your service relative to the neutral. You can do this at the dryer outlet if you have an electric dryer. Or you can measure a variety of 120 volt outlets.

Make sure you have an equal voltage on both legs.

John, Just to be clear, this should be done with a decent 120-volt load turned on.

Could you clarify that? You need a load to compare the voltages?
Link to post
Share on other sites

With a digital multimeter, measure both legs of your service relative to the neutral. You can do this at the dryer outlet if you have an electric dryer. Or you can measure a variety of 120 volt outlets.

Make sure you have an equal voltage on both legs.

John, Just to be clear, this should be done with a decent 120-volt load turned on.

Could you clarify that? You need a load to compare the voltages?

Jim's right. It's similar to a dry cell battery with a low charge. It has voltage unloaded but load it down a little and the voltage drops out.

On Randy's house, a loose or otherwise poor neutral connection somewhere might not manifest until it's loaded down.

Marc

Link to post
Share on other sites

Noise is now gone - actually, as of 2 or 3 days ago.

Coincidentally, about the same time, all the power was restored around town.

Don't have time to sit on hold with the local utility, but I suspect the linemen were certainly switching things around temporarily on the grid to get everybody back up and running.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...