# Fred # wrote:

"Bud--" wrote in message
.. .
# 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.

--
bud--

No humming or sizzling from my house panel even with the 240V electric range
on high. I just put on a stethoscope on every breaker in the house panel an
all I hear is the sound from the hot water heater pilot light transmitted
through the insulated stud wall and then through the electrical panel
cavity. What your hear must be a defective breaker/panel. Arching is pretty
bad and its an indication of meld down temperatures much like in welding.

Yes I do hear humming in electrical switchgears (2,000A or such) but that is
from the relays and respective CTs (control transformers).

Get used to sounds from the panel, the new AFCI breakers make a small
buzzing sound, presumably from an internal power supply for their
circuitry.

Pete C.