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#12693 - 08/14/02 07:22 PM humming panel
smokey Offline
Registered: 04/06/01
Posts: 41
Loc: cctxusa
went out on a service call today and swapped out a couple of bad the process i heard a humming sound coming from inside the panel. any suggestions on what may be causing the humming sound...
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#12694 - 08/14/02 07:37 PM Re: humming panel
George Corron Offline
Registered: 05/16/01
Posts: 717
Loc: Lorton, Va USA
OK, I've had a REAL bad day.
1) Something is loose, usually a breaker, could even be inside a breaker. Take the insulated end of your screwdriver and GENTLY put pressure on each breaker, when the humming stops, you found it. Could also be the buss bar, however.

Like I said, I had a real bad day. Went to work at 5 am, it's about 10:40pm, and I just got home, and we did not accomplish what we wanted I gotta be the first.

#12695 - 08/14/02 07:44 PM Re: humming panel
smokey Offline
Registered: 04/06/01
Posts: 41
Loc: cctxusa
what do u mean it dont know the words
#12696 - 08/14/02 08:05 PM Re: humming panel
golf junkie Offline
Registered: 04/22/01
Posts: 507
Loc: York, NE
Think about it a few'll come to 'ya.

#12697 - 08/15/02 02:18 AM Re: humming panel
sparky Offline
Registered: 10/18/00
Posts: 5303
Even brandy new installs seem to buzz with a motor load starting.
I imagine this is 60Hz vibrating the innards of breakers, as all else is new/tight?
#12698 - 08/15/02 03:14 AM Re: humming panel
Trainwire Offline
Registered: 03/15/02
Posts: 360
Loc: Strasburg,PA,USA
If nothin's hot, and it doesn't change by pressing on the breakers, I would say it's the nature of the panel, sometimes what it's mounted to makes it sound louder than it is, like the big board in the back of a piano. However if it's a buzz, or a fuzz sound rather than a hum
The other thing is, what was on? The water heater, dryer, a/c, some other heavy load?
Things like this keep a person up at night.
#12699 - 08/15/02 08:47 AM Re: humming panel
mamills Offline
Registered: 11/30/01
Posts: 745
Loc: Wharton, Texas, USA
Just a random thought...could it possibly be a mechanical noise from another piece of equipment or machinery being coupled to the panel through a conduit? I have also seen (aka heard) circuit breakers buzz when loaded pretty close to their ampacity.

George; sometimes I don't know the words either...HMMM, HMMM, HMMM...

Mike (mamills)
#12700 - 08/15/02 09:23 AM Re: humming panel
ElectricAL Offline
Registered: 10/10/01
Posts: 597
Loc: Minneapolis, MN USA
Is the doorbell transformer in one of the knockouts on the side of the panel? A really cheap one will have core laminations that flap in the wind.
Al Hildenbrand
#12701 - 08/15/02 11:24 AM Re: humming panel
ThinkGood Offline
Registered: 08/07/02
Posts: 1081
Loc: Milwaukee, WI
This is a real shot in the dark...and hopefully is not going to cause you more work for naught.

Maybe the cause of the humming is power harmonics?

There's a PDF file at (go to Application Notes, which is on the left menu, third up from the bottom).

The PDF is entitled "In Tune With Power Harmonics" and on page 4 mentions humming panels.

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