DIYbanter - View Single Post - Air conditioner humming outside but I have shut off the breaker

Joseph Meehan

George E. Cawthon wrote:
Joseph Meehan wrote:
wrote:
Hi,

I went out into the yard this evening and heard my air conditioner
humming. The unit hasnt worked properly since we had a major power
outage and so the only way to turn it on or off is at the breaker. I
removed the wires going into the breaker but the unit is still
humming. I openned the unit and the only power wires I can see are
the black/white/ground. It is a very old sears model and I cant
find any other shut off switch. What's going on!! Should I be
concerned about the humming and if so, how can I completely remove
the power to the unit without getting an electrician involved. I
even tried going breaker by breaker to see if there was a wire
touching but nothing stopped the humming

Thanks

You apparently did not shut off the right breaker. Remember
that your furnace is not likely on the same breaker as the A/C unit.
The A/C unit should have a 220V breaker and there should be a
shutoff in the immediate area of the unit.

Why not put the AC and the furnace on the same
breaker? Course my furnace was electric so the
power supply was 220 at 100 Amp. I just extended
the line to where I wanted the AC unit and put the
box and AC breaker there. No reason to use
separate lines since the AC and the furnace can't
run at the same time.

Course if you have a gas furnace and a 120V line
that's another story.

My only concern would be what size breaker was specified for the A/C.
If it specified a 50 amp breaker you are not protecting it (any the wiring
if it was sized to 50 amp) with a 100 amp breaker and that would not be
good.

It has been my experience which does not include electric furnaces as I
live in an area where gas is cheap, that furnaces are 120V devices.

--
Joseph Meehan

Dia duit