60 cycle hum at panel.


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Old 10-05-14, 02:03 PM
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60 cycle hum at panel.

I might come off as nuts with this one...

Placing ones ear on the cover of a circuit breaker panel, is it normal to hear a slight 60 cycle type hum when high draw loads are applied?

For example, if I have my ear up to the panel I can tell when someone turns on a heatgun or a coffee pot on one circuit... or if I have my ear up to the panel I can tell when my electric dryer is switched on.

When the loads switch off, so does the hum. Standing back 4' from the panel you wouldn't know unless you were really straining to hear it in a quiet environment.
 
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Old 10-05-14, 02:20 PM
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I'm pretty sure that's normal. It gets worse when there's harmonic loads such as dimmers.
 
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Old 10-05-14, 02:52 PM
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Since breakers are thermal/magnetic.... that hum is perfectly normal.
 
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Old 10-05-14, 03:14 PM
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When I was in the Navy, all the panels hummed to some extent. Lighting only panels not so much, but heavy loads like air handlers and winches...you could tell when they were powered up.

Don't notice it so much in my house, but then my panel is outside.
 
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Old 10-05-14, 07:35 PM
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A lot of times there is also a small doorbell transformer attached to a panel that causes the hum.
 
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Old 10-05-14, 11:28 PM
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When my Halloween lights were on earlier, my panel made a pretty good hum. Now that it's night and there's hardly anything on, I can barely hear anything.
 
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Old 10-06-14, 07:29 AM
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When my Halloween lights were on earlier
Already?? .......................
 
 

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