I have a portable generator that is rated at 7,500 watts run and about
14,000 start. I have a 10 seer (sp?) central AC. Is it possible to run the
AC from the generator if nothing elese is attached to the generator?
You still need full load amperage of both units. It would have been better
if the blower was 240 as well. Your generator puts out aprox 31 amps @240
volts continuous. The blower at 120 volt probably needs around 10 to 12
amps. Look on the nameplate of the condenser for the FLA
Really Highly Doubt it that you will be able to run the AC off of your
portable Generator - Seeing that it is going to be a pain in the ass to
have the 240 and the 120v coming off your generator at the same time, and
not to mention unless you have a really big portable generator its not going
to supply the current you need to get that A/C up and running. That
Start-Up Current Spike is going to be way over what your generator probably
can supply thus it will trip everytime.
My parents ran the A/C from their portable many times. Living in rural
NC they got their power knocked out a lot by storms. The 240/120 wasnt
an issue. They just back fed to the house load center and ran things
normally. They just couldnt run the A/C and water heater at the same time.
Joe Grassi wrote:
Practically all generators with a 7.5 kw output generate 120/240 volts. The
OP's issue is his combined starting and running current, which is still
unknown. If his unit is small enough, it would work fine
That ain't true.
Backfeeding through the main panel with a suicide cord is
illegal in some areas (should be in all areas), and backfeeding
without disconnecting from the utility drop is also generally
But a backfeed with a proper cord or wiring, plus a break-
before-make connection should be perfectly legit. And perfectly
safe. Farmers have been using huge double-pole/double-throw
switches for eons when they backfeed in an emergency.
Backfeeding through the main panel without a transfer switch is dangerous as
hell and in most places illegal.
Those huge double-pole/double-throw switches you mentioned are transfer
switches. By definition a "back feed" involves sending current through
a circuit from a point on the circuit that is not it's normal source of
Well we aren't no thin blue heroes and yet we aren't no blackguards to.
We're just working men and woman most remarkable like you.
Damn, I am the victim of my own failure to distinguish
vernacular vs NEC definitions. Thanks for the correction.
Now, if you can help me find a big-assed DPDT switch
that isn't overpriced by a factor of 10. (Yes, I know -
low production items always sell at a premium.)
Wouldn't a double pole cutoff be insufficient? I assumed the neutral must
also be disconnected from the power company's outside line. Isn't it going
to be carrying current when the generator is running?
My 2-ton 12 SEER heat pump outdoor unit draws about 6 to 8 amps at 240
volts when running. Start amps are about 20 to 25 amps. The indoor
unit draws about 2 amps at 240 volts. I use a window unit during power
outages, 120 volt, 1/2 ton. Then I can also run two refrigerators, a
microwave, the TV if the cable still works and some lights. I also run
a cord to each of two neighbors so they can run their refrigerators
too. If I ran my heat pump, it would reduce what Extra stuff I could
What size is your AC? That would determine the answer. If it is much
over 3 tons, probably not.It depends on the surge rating of the
generator and if you have a hard start kit on your ac. My heat pump
has one, but I still prefer the window unit. Why strain an expensive
I mentioned in another post I am leaning toward the window unit plan now
(thanks to all the good info here). I am considering three or four 6 btu
units spread throughout the house. My generator is 7500 KW run and 13.5 KW
start, so I'm thinking I should have plenty to do about what you described
you do. Some lights, window AC, refridge, micorwave, TV and computers.
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