Buzzing Panel

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bjp_ne_elec

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Got an email yesterday, but by the time I read it, it was too late to call the sender. It's a commercial account, and the guy that just took over the facilities function (his background would make him not my first choice - but he mainly lines up outside contractors to deal with any needs or problems). He indicates in the email that "there is a loud buzzing sound coming from the breaker panel". Other than an overloaded/weak breaker - which would be my first inclination - have any of you run in to any other reason for a buzzing coming from a panel?
 
I have seen breakers buzz. Try just changing it out. Check the buss bar as you do it.

To isolate you can start by turning off breakers one at a time. Make sure you are not shutting down any computers etc. without them knowing.
 
bjp_ne_elec said:
If it is an issue with a bus bar connection - how do you isolate? I'm familiar with the area this panel is in, and there are no contactors.
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do like Dennis suggests or use a non-contact thermometer, it would be in the hot spot in the panel, or you could just feel the breakers for the vibration and heat.
 
When MCCB's are in the long time potion of the trip curve they will buzz, this could be from an overload or a defective CB.

The second thing would be a loose connection though this should become evident VERY FAST as the equipment sustain damage.

The third issue could be some peripheral equipment that is buzzing and mistakenly thought to be a CB.

Fourth if it is HV distribution it could be corona

A UE Systems ultra probe works well for isolating buzzing

http://uesystems.com/prod_up_100.asp
 
If this is an older breaker with electro mechanical trip units it is probally the trip unit (OD's) buzzing, they tend to do that near pickup.
 
we have 2 ways of detecting 1. i/r camers.2. we have a sound gun that we have been trained on and what to listen for.
I/R will tell you where the hot spot is, and sound will pinpoint where it is.
 
ultramegabob said:
do like Dennis suggests or use a non-contact thermometer, it would be in the hot spot in the panel, or you could just feel the breakers for the vibration and heat.
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UltraMeagBob - any recommendations on a non-contact thermometer? That's something, along with UE system that BrianJohn suggested, that I'll have to add to my "tool kit". I did call on the UE system and it's just under $1K - a little pricey - but worth it's weight in gold if it helps you pinpoint a problem.
 
bjp_ne_elec said:
UltraMeagBob - any recommendations on a non-contact thermometer? That's something, along with UE system that BrianJohn suggested, that I'll have to add to my "tool kit". I did call on the UE system and it's just under $1K - a little pricey - but worth it's weight in gold if it helps you pinpoint a problem.
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You are shooting in the dark here, a hot spot is probally not your problem (Could be, but unlikely).

What type of breaker is this?
 
What type of breaker is this?[/QUOTE]

Crouse Hinds - I've got noted Type H - but I don't run in to Crouse Hinds much. It's not a Federal Pacific - which I know are notorious for having issues with where they plug in to the bus.
 
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No fair editing when I am repling :)

Is it HKD? Those have a thermal magnetic element that could buzz. Have you checked loading on this breaker?
 
Yeh Zog - I just wrote you a PM. Sorry about that - you're too quick. The only thing I got off the panel cover was "Type H" - so I'll have to get in the facility.

I have not checked the load, but plan on it once I get to the facility. Was going to at least see if I could determine what breaker it was. Waiting for a call back from the maintenance guy, as I don't want to drive over, if they'be left for the day.
 
bjp_ne_elec said:
UltraMeagBob - any recommendations on a non-contact thermometer? That's something, along with UE system that BrianJohn suggested, that I'll have to add to my "tool kit". I did call on the UE system and it's just under $1K - a little pricey - but worth it's weight in gold if it helps you pinpoint a problem.
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I have a cheapie no name brand I picked up somewhere, but if I was going to go out and buy a name brand one, somthing like this fluke would probably do the job.

http://www.transcat.com/Catalog/productdetail.aspx?itemnum=98142TE
 
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Maybe the contacts in the main breaker are wore out, This is the only loud buzz Ive ever herd, and quiet buzz if its a breaker
 
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