# Fred # wrote:
A humming sound from breakers is pretty normal.


Those breakers are spring loaded and latched in the closed position
(presuming nothing is loose within the breaker or the panel) so what cause
the humming from a small panel breaker?


The power is AC - 60Hz. With current flow a 60Hz magnetic field is
produced which can cause small movement of parts within the breaker
causing a hum. The field can act directly on magnetic parts, or the
fields of 2 nonmagnetic parts conducting current can interact. You
wouldn't hear it at low current and it wouldn't be very loud with the
current likely drawn in a house panel. I have heard it on loaded 15 &
20A breakers. The sizzling sound from an arc isn't very loud either.

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bud--