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Calling all electricians


John Ranalletta

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John Ranalletta

Having added a generator to the emergency supply kit, I need to rewire the furnace. It is a gas furnace with 120v fan motor. There is a switch box and switch mounted on the furnace to interrupt power to the furnace motor for servicing.

 

It seems the most simple solution would entail replacing the existing switch box and switch with an outlet and terminating the leads from the furnace motor with a male plug. When running on house power, the motor would be plugged in receptacle or connected to the generator during emergencies.

 

I'm not attempting to install an automatic cut over and I want to make it impossible to energize the supply line back to the circuit breakers and beyond. Is there a switch that would accomplish the same objectives?

 

All suggestions welcomed.

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Joe Frickin' Friday

If you're going to do the switchover manually, it seems to me the simplest thing is to shut off the main breaker, then plug your generator into an ordinary outlet to energize your whole house. To avoid overloading the generator, you could switch off various non-essential items, either via breakers at the panel, or simply by unplugging things.

 

This way your gen could keep the furnace and the fridge/freezer running (assuming adequate capacity to power both simultaneously).

 

If you're dead set against even potentially energizing the whole house, then of course this approach is out, but it seems like the easiest way - no wiring required - provided you're smart enough to kill the generator before turning the main breaker back on. Safety tags/locks could make this approach reasonably safe.

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If you're going to do the switchover manually, it seems to me the simplest thing is to shut off the main breaker, then plug your generator into an ordinary outlet to energize your whole house. To avoid overloading the generator, you could switch off various non-essential items, either via breakers at the panel, or simply by unplugging things.

 

This way your gen could keep the furnace and the fridge/freezer running (assuming adequate capacity to power both simultaneously).

 

If you're dead set against even potentially energizing the whole house, then of course this approach is out, but it seems like the easiest way - no wiring required - provided you're smart enough to kill the generator before turning the main breaker back on. Safety tags/locks could make this approach reasonably safe.

Also quite illegal in most jurisdictions. By code a generator must have a full disconnect installed. Power company linemen take a dim view of any installation that could even potentially back feed onto their lines.

 

In sort, don’t go there. Install a disconnect.

 

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It seems the most simple solution would entail replacing the existing switch box and switch with an outlet and terminating the leads from the furnace motor with a male plug. When running on house power, the motor would be plugged in receptacle or connected to the generator during emergencies.

That's not a bad solution, or you can just use any heavy-duty DPDT switch so that one position feeds the motor from the AC mains and the other from a standard 110-volt plug (that you supply.) This would make it impossible to backfeed.

 

But that's such a waste of an EU2000... don't you want to power other loads as well, such as your refrigerator, some lighting, TV, etc.?

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I think the man is looking for a simple solution and not interested in a complete substation...

 

What you have proposed is acceptable. Most jurisdictions allow the use of an appliance cord from the furnace to the receptacle, provided the cord is UL listed and of adequate size for the load being served.

 

MB>

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Also quite illegal in most jurisdictions. By code a generator must have a full disconnect installed. Power company linemen take a dim view of any installation that could even potentially back feed onto their lines.

 

In sort, don’t go there. Install a disconnect.

 

<<<<< Otherwise known as a transfer switch>>>>>

 

And your installation must be approved by your local utility provider and municipality.

 

MB>

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The simple solution I was considering (when I ever decide ot plunk down $700 on a "good" small generator) is switching off the furnace at it's local disconnect, then unplugging (uses spade connectors) the L1 and Neutral from the control board, then making up a extension cord with spade connectors to take their place.

 

However, there are some very simple local furnace disconnects for use with back-up generators.

 

I agree, that an expensive, whole house main breaker transfer switch is overkill if your only goal is to run a furnace and maybe a couple lights... which is my plan. Acutally I was going to switch between the TV/Sattelite dish system and the furnace.

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John Ranalletta

Thanks, all...

 

The DPDT switch looks like a the way to go for a positive disconnect. This is a list of appliances (plus some lighting)

that I'd need to energize in a power-out situation:

 

gen.JPG

 

The refrig and freezer only need to be run every few hours to maintain temp; the sump pump, only in a rain event

and the furnace, only in late fall, winter and early spring.

 

The plan is to fabricate a couple of heavy duty extension cords terminated in 2&4-outlet boxes. The sump,

furnace and freezer are within a 10-foot radius. Another gang box would serve the kitchen and minimal ambient

lighting and cable/modem/computer.

 

Having fuel at the ready isn't a big issue as I'll get a syphon device to get fuel from the cars and if

necessary in addition to having 10 gallons of fuel portable containers always on hand.

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Joe Frickin' Friday
Also quite illegal in most jurisdictions. By code a generator must have a full disconnect installed. Power company linemen take a dim view of any installation that could even potentially back feed onto their lines.

 

Heh... shoulda prefaced my suggestion by noting that I'm definitely not a professional electrician...

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Also quite illegal in most jurisdictions. By code a generator must have a full disconnect installed. Power company linemen take a dim view of any installation that could even potentially back feed onto their lines.

 

Heh... shoulda prefaced my suggestion by noting that I'm definitely not a professional electrician...

 

The way to do it would be to throw the main so no power is going out and then trip all the breakers in the house. Be sure you have a good earth ground and not depending on the power grid of neutral. Turn them back on only as needed. Freezers and refridgerators only need a couple of hours a day. electric furnaces, stoves, water heaters, and well pumps eat up a lot. I've gotten by just fine with a woodstove insert and the heat pump fan on bypass, cooking on a camp stove, and taking showers at the gym.

 

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Sorry for maybe stating the obvious, but I'm going ot jump on a soapbox and ask: Is it sooo, hard to just unplug "critical" appliances and use extension cords for an emergency??? It seems to me that unless you live somewhere that has power outages frequently (>1 per year) and for extended periods, it's not reasonable ot violate codes and take a risk of killing lineman or burning down your house, jsut because you're lazy.

 

It's probably unfair for me to criticize because I happen to live in an area where the power company proatively and aggressively trims and removes trees to prevent downed lines. When I lived in Michigan, I frequently saw "chunks" of tree limbs hanging on powerlines, indicating they waited until the tree grew into the lines before doing something about it. No suprisingly pwoer went out at least 1-2 times per year for at least 1 day. We've never lost power for more than a few hours in my area i nthe 5 years I've lived here. But pwoer companies are like government agencies, somehow spending $100k trimming trees to avoid $200k in overtime costs doesn't add-up when you're approving your budgets.

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you can use something like this on your main panel:

 

http://ecatalog.squared.com/techlib/docdetail.cfm?oid=0900892680126e4f

 

Or if you have a critical sub panel like I have (but no generator :dopeslap:):

 

http://ecatalog.squared.com/techlib/docdetail.cfm?oid=09008926801a669f

 

The second one I have and it did pass electrical building inspection when I reserviced my house to 400 amps :Cool:.

 

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