Hi,
In the event of a power failure I would like to be able to power my
fridge as well as my furnance... those are really the only two
requirements. Is there a cheap way to do this? Fridge, obviously I can
run an extension cord... but what about the furnance?

I don't suppose it's safe to 'backfeed' an electrical system.. ie flip
the main off, and then plug the generator into say a 20Amp outlet, and
then run the furnance through the backfeed of the electrical system as
long as I don't use anything more then 20Amp circuits?

~ Matt

Matt wrote:
Hi,
In the event of a power failure I would like to be able to power my
fridge as well as my furnance... those are really the only two
requirements. Is there a cheap way to do this? Fridge, obviously I can
run an extension cord... but what about the furnance?

I don't suppose it's safe to 'backfeed' an electrical system.. ie flip
the main off, and then plug the generator into say a 20Amp outlet, and
then run the furnance through the backfeed of the electrical system as
long as I don't use anything more then 20Amp circuits?

~ Matt

Please read the thread on this group which has been raging for weeks:
" Electrical/Generator question"

For your furnace, break the hardwired connection to it and equip the
thing with a cord and plug. Provide a receptacle on the furnace ckt
where you would normally have it plugged in. To run it off genny,
plug furnace cord into extension.

Jim

A transfer panel is best

I recently saw a small transfer panel at the local Menards which handled
4 or 6 circuits. It basically mounted near you existing panel. Each
circuit that you want to transfer is then routed into the transfer panel
first and then to the main panel. When you are in the transfer mode,
there is a mechanical interlock which prevents backfeeding the main
panel. If the home is wired with romex, the job is fairly easy ... with
conduit, a bit harder.

Matt wrote:

Hi,
In the event of a power failure I would like to be able to power my
fridge as well as my furnance... those are really the only two
requirements. Is there a cheap way to do this? Fridge, obviously I can
run an extension cord... but what about the furnance?

I don't suppose it's safe to 'backfeed' an electrical system.. ie flip
the main off, and then plug the generator into say a 20Amp outlet, and
then run the furnance through the backfeed of the electrical system as
long as I don't use anything more then 20Amp circuits?

~ Matt

Generac at Lowes has a complete kit for 2-300, buy it seperatly at
menards it is 400+ The kit is often free with a gen purchase

Matt wrote:
Hi,
In the event of a power failure I would like to be able to power my
fridge as well as my furnance... those are really the only two
requirements. Is there a cheap way to do this? Fridge, obviously I
can run an extension cord... but what about the furnance?

I don't suppose it's safe to 'backfeed' an electrical system.. ie flip
the main off, and then plug the generator into say a 20Amp outlet, and
then run the furnance through the backfeed of the electrical system as
long as I don't use anything more then 20Amp circuits?

You will need:
1. An old lawnmower.
2. An 12v auto alternator.
3. A car battery.
4. An inverter (12vdc = 120vac)
5. Wire, bolts, plugs, pulley, belt, other small stuff.

Check the web for plans.

You will need:
1. An old lawnmower.
2. An 12v auto alternator.
3. A car battery.
4. An inverter (12vdc = 120vac)
5. Wire, bolts, plugs, pulley, belt, other small stuff.

I bought a "battery isolator" and connected it to my jeep's alternator to
charge a second battery which powers a 3500 watt inverter. The isolator
prevents the main battery from draining so the car can be restarted. A car
can safely idle for hours to charge the battery and run the inverter, while
consuming little fuel.

When hurricane Isabel hit and power was out for over a week, I had plenty of
power to run the refrigerator for several hours a day (the ice never even
melted). I could run flourescent lights and my computer all day. Among the
advantages of this is it's MUCH quieter than a generator (silent when the
car isn't idling), lots easier to store and very portable.

On Tue, 23 Nov 2004 10:57:02 -0500, Matt wrote:

In the event of a power failure I would like to be able to power my
fridge as well as my furnance... those are really the only two
requirements. Is there a cheap way to do this? Fridge, obviously I can
run an extension cord... but what about the furnance?

I don't suppose it's safe to 'backfeed' an electrical system.. ie flip
the main off, and then plug the generator into say a 20Amp outlet, and
then run the furnance through the backfeed of the electrical system as
long as I don't use anything more then 20Amp circuits?

You need a transfer switch. Couple hundred bucks for most small
generators, but you may need an electrician to install it (check local
code requirements).

Alternatively, an electric space heater or portable propane heater
will cover those needs.

Of course, why do you need a fridge *and* a heater? If it's cold
enough to need a heater, just toss the fridge contents out in the
snowbank...

Jeff

Jeff Cochran wrote:
On Tue, 23 Nov 2004 10:57:02 -0500, Matt wrote:


In the event of a power failure I would like to be able to power my
fridge as well as my furnance... those are really the only two
requirements. Is there a cheap way to do this? Fridge, obviously I can
run an extension cord... but what about the furnance?

I don't suppose it's safe to 'backfeed' an electrical system.. ie flip
the main off, and then plug the generator into say a 20Amp outlet, and
then run the furnance through the backfeed of the electrical system as
long as I don't use anything more then 20Amp circuits?


You need a transfer switch. Couple hundred bucks for most small
generators, but you may need an electrician to install it (check local
code requirements).

Alternatively, an electric space heater or portable propane heater
will cover those needs.

Of course, why do you need a fridge *and* a heater? If it's cold
enough to need a heater, just toss the fridge contents out in the
snowbank...

Jeff

Jeff,
Very good observation so basically it looks like my easiest plan of
attack is to wire an outlet down by the furnance... if it's warm outside
I can run the fridge.. if it's cold the furnance.. just route 1 or 2
orange extension cords to the correct appliance and bingo

Good transfer panels have 2 watt meters to balance each leg of the
generator. A 6 circuit Generac is a complete kit with cable , plugs ,
exterior box , sockets and it is pre wired and labeled, an easy
install. 200 for the kit and apx 200 for the instal. Worth the money
for flexibility and saftey

Very good observation so basically it looks like my easiest plan of
attack is to wire an outlet down by the furnance... if it's warm outside I
can run the fridge.. if it's cold the furnance.. just route 1 or 2 orange
extension cords to the correct appliance and bingo

He was either joking, or has never been through a power outage.
Get yourself a transfer switch if you can afford it, and some extension
cords if you can't.
As long as we are on the subject, Any but the best generator can burn out a
new furnace. I have a Honda that gives better power than the utility, but
my HVAC tech recommended against using it without putting it on a scope
first to confirm the quality.(Since I don't have a scope, I am going to live
dangerously; but it would be a good idea.)

As long as we are on the subject, Any but the best generator can burn
out a new furnace. I have a Honda that gives better power than the
utility, but my HVAC tech recommended against using it without
putting it on a scope first to confirm the quality.(Since I don't
have a scope, I am going to live dangerously; but it would be a good
idea.)

A furnace has lots of components - what exactly would a generator "burn out"
and why, and what would one be looking for on a scope?

The only thing I could think possibly is THD which would be mighty hard to
eyeball on a scope (unless you drew a perfect sinewave on the face to
compare and even then it's only an estimate). That or extreme continuous
voltage or frequency variations or spikes - in which case it wouldn't be a
good power source for practically anything.

That's exactly what I was thinking. However, some newer furnaces, like
my 10 year old unit, have electronics. BTW, I have run my furnace on my
cheap 4KW Coleman genset with no problems.

John Harlow wrote:
As long as we are on the subject, Any but the best generator can burn
out a new furnace. I have a Honda that gives better power than the
utility, but my HVAC tech recommended against using it without
putting it on a scope first to confirm the quality.(Since I don't
have a scope, I am going to live dangerously; but it would be a good
idea.)


A furnace has lots of components - what exactly would a generator "burn out"
and why, and what would one be looking for on a scope?

The only thing I could think possibly is THD which would be mighty hard to
eyeball on a scope (unless you drew a perfect sinewave on the face to
compare and even then it's only an estimate). That or extreme continuous
voltage or frequency variations or spikes - in which case it wouldn't be a
good power source for practically anything.

Art Todesco wrote:
That's exactly what I was thinking. However, some newer furnaces,
like my 10 year old unit, have electronics. BTW, I have run my
furnace on my cheap 4KW Coleman genset with no problems.

Electronics would be the least of my worries; anything worth a crap would
have varistor protection and decent brownout and overvoltage protection.
Harmonics would be most injurious to motors, and it'd have to be pretty
severe - motors can run fine on MSW inverters which have gobs of harmonics.

If that's your worry, then go down to your local computer junk store and
pickup a power filter... at least here we have a local prison that has
the inmates work on old DOJ stuff that is offloaded.. great stuff.. huge
UPS systems for like $50... power filtration boxes (little things that
you can lug around).. good enough to put in line with a generator and
run a computer off of even.

If the furnance was THAT suseptable to power flux, then I petter put a
surge protector on it anyway!!!

John Harlow wrote:
Art Todesco wrote:

That's exactly what I was thinking. However, some newer furnaces,
like my 10 year old unit, have electronics. BTW, I have run my
furnace on my cheap 4KW Coleman genset with no problems.


Electronics would be the least of my worries; anything worth a crap would
have varistor protection and decent brownout and overvoltage protection.
Harmonics would be most injurious to motors, and it'd have to be pretty
severe - motors can run fine on MSW inverters which have gobs of harmonics.