why would this buzz??

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Ponchik

Ponchik

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Location
CA
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Electronologist
Today I noticed when I connect the Neutral terminal of a "Homeline" AFCI to the frame of the panel there is a buzzing noise. The breaker is connected to an energized bussbar, however, there are no conductors connected to the breaker and the breaker is off. :?:?

I will try to upload the video.
 
edward said:
Today I noticed when I connect the Neutral terminal of a "Homeline" AFCI to the frame of the panel there is a buzzing noise. The breaker is connected to an energized bussbar, however, there are no conductors connected to the breaker and the breaker is off. :?:?

I will try to upload the video.
Click to expand...

Did the other AFCI breakers in the panel buzz? I've never encountered this. My gut is it's a bad breaker.
 
I'm guessing it is something else buzzing and when the AFCI is installed it changes the harmonics making it appear to be from that.

Simple test, move the breaker to a different spot or put a regular breaker there just to check.
 
I was in a hurry to get it hooked up so I can turn the lights ON. I am going back tomorrow to do more probing. Very interesting.

BTW, it did turn and stay ON just fine.
 
JFletcher said:
wag, but the torque from that breaker being pried is causing problems elsewhere. My first step would be a different breaker in a different position.
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I did not pry or have any torque on the terminal.
 
Did you measure voltage between neutral and EGC?

I don't know if AFCI's open the neutral - GFCI's do. If neutral is opened by the device - then in your video the device was off, there is no connected neutral load conductor, I wouldn't expect any thing to happen. If the breaker were "on" I could see this happening, and possibly even should trip.
 
kwired said:
Did you measure voltage between neutral and EGC?

I don't know if AFCI's open the neutral - GFCI's do. If neutral is opened by the device - then in your video the device was off, there is no connected neutral load conductor, I wouldn't expect any thing to happen. If the breaker were "on" I could see this happening, and possibly even should trip.
Click to expand...

At first I did measure voltage between the neutral lug of the AFCI and the grounding, the neutral bar and the energized conductors ZERO volts.

I did not get a chance to do any tests today.
 
ramsy said:
I noticed 2 relatively empty buss-bars with loose screws in close proximity to breaker. Try landing those screws.
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Square D neutral/ground bus terminals are "backed out" from the factory. But if no conductor is landed in them shouldn't matter one bit. The breaker in his video is a "plug on neutral" breaker and the neutral plugs on to the neutral bus at the solid segment between every "group of two" conductor landing terminals.
 
kwired said:
Square D neutral/ground bus terminals are "backed out" from the factory. But if no conductor is landed in them shouldn't matter one bit. The breaker in his video is a "plug on neutral" breaker and the neutral plugs on to the neutral bus at the solid segment between every "group of two" conductor landing terminals.
Click to expand...

Even if one of those loose neutral screws is touchoing the under side of breaker?
 
ramsy said:
I noticed 2 relatively empty buss-bars with loose screws in close proximity to breaker. Try landing those screws.
Click to expand...

Those screws even though are back out they are tight not loose to vibrate.
 
edward said:
Those screws even though are back out they are tight not loose to vibrate.
Click to expand...

Breaker appears "Off" during video, with no conductors terminated, so how can electronic noise occur without power?
If noise is mechanical, what about other loose items, breaker lugs, etc.?
 
ramsy said:
Even if one of those loose neutral screws is touchoing the under side of breaker?
Click to expand...
The factory "backed out" position shouldn't be an issue, I can't tell you offhand if it is possible to back them out enough to have any impact on the plug on neutral breaker connection performance, but would guess they are capable of handling maximum rated conductor size in the bar and still plug a breaker over that position.

ramsy said:
Breaker appears "Off" during video, with no conductors terminated, so how can electronic noise occur without power?
If noise is mechanical, what about other loose items, breaker lugs, etc.?
Click to expand...
I mentioned this - not sure if AFCI's open the neutral but if they do then that shunting of EGC to the breaker neutral terminal shouldn't have done anything with the breaker in the off position.
 
Maybe my ears aren't as good as they used to be so I got my headphones out and I still can't hear the buzzing you are talking about. Lots of background noise and what did prying with the screwdriver do?

-Hal
 
hbiss said:
Maybe my ears aren't as good as they used to be so I got my headphones out and I still can't hear the buzzing you are talking about. Lots of background noise and what did prying with the screwdriver do?

-Hal
Click to expand...

No Prying. I was just touching the neutral lug of the breaker to the cabinet.

I tried to do more testing today but I could not keep the lights off because the tile guys were working.

I will do it when I get a chance.
 
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