How to hook up gas generator for central a/c unit in emergency
bd...@ichange.com
and fan/blower/thermostat) from a portable 240V gasoline generator on
those odd occasions when the power goes out for several hours in the
summer.
Is this possible?
Can someone tell me what I'd need to do? Would I need a 'panel' to shield
/cut out the normal house current from the a/c circuit for the generator
so that it wouldn;t be fried when the current did come back on?
Any help is greatly appreciated.
Thanks,
Bruce
Kirk Kerekes
> I would like to be able to run my central air unit (including compressor
> and fan/blower/thermostat) from a portable 240V gasoline generator on
> those odd occasions when the power goes out for several hours in the
> summer.
>
> Is this possible?
>
Yes, but it will be pretty expensive. You could stay in a motel room for a
long time for what it is going to cost.
--
Kirk Kerekes
-----------------------------------------
- Perfection is Not an Available Option -
-----------------------------------------
David Pritchett
>In article <4l6m52$q...@ias2.ichange.com>, bd...@ichange.com wrote:
>
>> I would like to be able to run my central air unit (including compressor
>> and fan/blower/thermostat) from a portable 240V gasoline generator on
>> those odd occasions when the power goes out for several hours in the
>> summer.
>>
>> Is this possible?
>>
>
>Yes, but it will be pretty expensive. You could stay in a motel room for a
>long time for what it is going to cost.
>
>--
>Kirk Kerekes
>
It's going to take a 10,000 watt plus generator to run the AC and the
blower, allowing for a few lights and a TV. Better turn off the freezer
and refrigerator and don't run the coffee pot or AC stove while that's
going on!
You can get a rough estimate using the formula P=E*I (power in
watts=voltage*current). To calculate it exactly, there's AC vector math,
but you'll be close. Look at all the labels on the devices you wish to
run, add up the AMPS and multiply times the voltage that the device uses.
Philippe Habib
>I would like to be able to run my central air unit (including compressor
>and fan/blower/thermostat) from a portable 240V gasoline generator on
>those odd occasions when the power goes out for several hours in the
>summer.
>Can someone tell me what I'd need to do? Would I need a 'panel' to shield
You need to get a generator transfer switch and a generator. Some come on
automatically, they cost about $4k. You can get a manual switch for about
$300 and add your own generator.
I just bought one made by Reliance. Call (414)634-6155 and ask for a
distributor near you. You buy from the distributor. If they don't stock
it, Reliance can drop ship it to you by UPS.
I paid $254.12 for a 5000 Watt, 6 circuit unit, from my local distributor.
This question keeps comming up, maybe it should be in a FAQ.
.
bd...@ichange.com
way to isolate that part of the circuit from the main circuit.
Someone posted a similar thought on this newsgroup for hooking up a gas
furnace to a generator (he actually did this). This was sometime last
year but I don't remember what was said exactly.
Bruce
Mickey Adams
On 19 Apr 1996 00:18:42 GMT, bd...@ichange.com wrote:
>I would like to be able to run my central air unit (including compressor
>and fan/blower/thermostat) from a portable 240V gasoline generator on
>those odd occasions when the power goes out for several hours in the
>summer.
>
>Is this possible?
>
>Can someone tell me what I'd need to do? Would I need a 'panel' to shield
>/cut out the normal house current from the a/c circuit for the generator
>so that it wouldn;t be fried when the current did come back on?
>
>Any help is greatly appreciated.
>
>Thanks,
>Bruce
>
Hey Bruce:
Go to your electrical supply house and buy yourself a length of 10
gauge/ 3 wire shielded cable long enough to reach from your generator
outdoors to your electric clothes dryer receptacle or electric stove
receptacle inside your house. Get a plug for one end of the wire to
fit the 240V outlet on the generator and get a plug for the other end
to fit your 240V dryer/stove outlet in the house. Turn off the main
circuit breaker which separates your house from the incoming power
line. Now turn off all the little circuits that control all the
appliances in your house. Fire up your generator and your circuit
breaker box is energized. Now pick out the one breaker that controls
the power to your air conditioning and switch it on. Hopefully, your
generator is putting out enough power to run your Air Conditioner. I
got this tip off this newsgroup last week and haven't had a chance to
try it yet myself but this is what is called "backfeeding power" into
your house. I called my power company and they said this is an
acceptable method of delivering temporary power into your house but
you better get several generators if you like to use lots of
electricity!
Paul F. Blomberg, P.E.
mic...@super.zippo.com (Mickey Adams) wrote:
While this works, it is quite !dangerous! and violates the national
electrical code. The "cheater" cord you make will have exposed plugs
on both ends which are energized. Unplugging the cord is dangerous.
Its an accident waiting to happen. Also, failure to properly open and
close all the breakers in your fuse box in the proper order could burn
up your generator or even kill someone (like the electric company
lineman who is trying to repair the deenergized line and suddenly you
energize it).
An electrician can make the required electrical box modifications to
ensure safety. I'd really like to know what power company that said a
cheater cord is acceptable. Having worked several storm restorations
to get peoples power back, portable generators are one of the greatest
threats to workers and your neighbors. If you accidentally backfeed a
line that is down and don't have the proper fuse/circuit breaker
coordination, the downed line may be energized. I hope nobody decides
to touch that line.
Paul.
Northeast Utilities.
Dan Hicks
In many parts of the country what you propose is illegal. It's too easy
to fail to turn off the main breaker and end up backfeeding the power
line. This is very dangerous to the linemen who are trying to fix the
problem.
A better approach would be to put the AC itself on a plug, so you can
plug it directly into the generator. Or get the proper cutover switch.
Dan Hicks
Hey!! My advice is free. Take it for what it's worth.
http://www.millcomm.com/~danhicks/
Frank Erskine
In article <318cef3...@snews2.zippo.com>, Mickey Adams
<mic...@super.zippo.com> writes
A better idea might be to wire from your generator to a separate outlet
adjacent to your central air unit (or whatever), them when the mains
goes down, plug the unit into the new outlet after starting the
generator.
Label the two outlets "Mains" and "Generator" so that you remember which
is which.
--
Frank Erskine
Sunderland
England