House electrical panel buzzing

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House electrical panel buzzing every 5 minutes.

Is a loose wire / connection causing the buzz ?
Buzz lasts about a half second.
 
Feel your breakers, see if any one is warmer than the others. If you get real lucky you'll have a finger on it when it buzzes.
 
You'll sometimes get a buzz that you can hear at the breaker when a CFL or something else with poor phasing of the rectifier turns on.

I noted this once when I had a motion sensor light with CFL floods that would turn on. I suspect there was an LC resonance in the circuit. Some motor inrush currents will cause a 60 or 120 Hz buzz for a time as the inrush decays and the motor spins up to a point of synchronization with the AC 60Hz sine wave.

Still best to ensure its not arcing (a sharp, crackling sound), or a breaker near its trip point. Keep in mind that breakers have operating curves. A 20A breaker doesn't open immediately at 21A, but will at 2000 (short). But still if a circuit is near overload and the breaker is getting close to opening up, the circuit should be evaluated to be redone.

Also note that big electronics will naturally give a 60Hz buzz when energized. Stand next to a big transformer and listen carefully. But always smart to get it checked out if you're not sure, as you sure don't want an electrical fire.
 
I had a channel bank in a hospital drop the last 2 lines. Far as I could tell, the trouble was the AC power . The mux was in a utility room. Fluorescent lights, motors all kinds of stuff on a 15 amp breaker. I borrowed an extension cord plugged into a different circuit to cure it.
 
Hmmm...what's cycling every 5 minutes?

I regularly check all 220VAC connections/terminals/breakers/etc. with aluminum wire to be sure they are tight. These have a habit of loosening over time and will arc on heavy loads like A/C units. They should be checked & tight on both ends of the cable.

Arching & smoke scared the bejesus out of a neighbor: He called the fire dept. Cause was a loose Al connection on the indoor A/C unit. Fortunately it was inside a metal box.

Had another friend with evidence of Al vaporization, black streaks and obvious arching in the same location as above. I didn't want to fix it for liability reasons, so showed it to him. He called a licensed electrician to fix it. Dielectric grease should be used on them to keep oxidation from forming.
 
Had a old Square D panel, with a hefty 90 amp breaker, for electric central heat.

It was internal, a bad breaker, ended up replacing the entire panel, being so old.
 
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I've never had an electrical panel make noise. I suppose if it's a mediocre quality system then it might just be normal vibrations. However, if it were mine I'd start by turning off 1/2 of the breakers and wait 5 minutes. If it buzzes again, then it's the half that are still on. Turn 1/2 of those off, wait 5 minutes, and listen for the buzz. Narrow it down to the breaker(s) that are buzzing, and then figure out what's going on with it/them.

Circuit breakers do go bad and wires can work themselves loose.
 
Originally Posted By: Mr Nice
Electrical panel is 45 years old.

Thanks for all the advice and tips.


45 years old? I sure hope it isnt a Federal Pacific box.
 
It's made by ITE Imperial Corp.

I called Florida Power and Light, they sent Pike Electric (subcontractor) and it turned out there was a loose connection to the meter. Poor connection was causing intermittent half second buzz.
 
I had a loose neutral at my transformer once. The voltage was going sky high making the old time incandescent light bulb ring when the wind was blowing. I checked the voltage at an outlet and read over 165V. I killed the panel and called the electric company.
 
Originally Posted By: Pop_Rivit
I've never had an electrical panel make noise. I suppose if it's a mediocre quality system then it might just be normal vibrations. However, if it were mine I'd start by turning off 1/2 of the breakers and wait 5 minutes. If it buzzes again, then it's the half that are still on. Turn 1/2 of those off, wait 5 minutes, and listen for the buzz. Narrow it down to the breaker(s) that are buzzing, and then figure out what's going on with it/them.

Circuit breakers do go bad and wires can work themselves loose.


If youre denying that 60Hz noise, amongst others, dont occur in electric equipment, Id have to question your hearing and your knowledge. Please do define what a "vibration" is in terms of electrical and magnetic phenomena, please...

All the same, be safe, OP, and I concur with the troubleshooting approach. Youll be able to neck it down quite likely.
 
Originally Posted By: JHZR2

If your denying that 60Hz noise, amongst others, dont occur in electric equipment, Id have to question your hearing and your knowledge. Please do define what a "vibration" is in terms of electrical and magnetic phenomena, please...

All the same, be safe, OP, and I concur with the troubleshooting approach. Youll be able to neck it down quite likely.

Yep..for sure.
 
Originally Posted By: Vern_in_IL
Had a old Square D panel, with a hefty 90 amp breaker, for electric central heat.

It was internal, a bad breaker, ended up replacing the entire panel, being so old.



I had two rental properties with "Federal Pacific" breaker panels. It cost a small fortune to replace both of those.
 
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