Plug in for home furnace

[4spdragtop]

Hi all, i recently had to wire up furnace to an ext cord plug due to power outage. And would like to make this an option so I don't have to undo/redo wiring.
The furnace has a junction box(feed from breaker, furnace and feed "from" kill switch). The "kill", on/off switch is mounted separately from junction box and only has 1 wire to it. Unlike a "normal" switch with an in/out that would have 2 wires.
Is there a box/plug so I can plug ext cord in from generator?
Thanks
Steve

 

[MDchanic]

You could do it with a single "3-way" switch as the selector on the "hot" wire, and a recessed "motor home" male plug in a box.

This would NOT be to code (as far as I know), but would be reasonably safe, as the "hot" wire could only be connected to either the house power, OR the male plug, but never to both.

I'd do it in a separate large box, and label it very clearly.

– Eric

 

[mpgmike]

There is something called a Transfer Switch that allows you to legally do exactly what you're wanting to do -- and it meets code! Here is a picture of what I have in the shop. We added some solar, but wanted to be able to switch back and forth if the need arose. The main breaker box is to the right. If I want a certain circuit to draw from my solar, the switch goes up. If I want to draw from the grid, it goes down. In the middle it is completely disconnected. This particular box has two 220 circuits (left 4 switches) and 6 120 circuits. Each has a breaker for further protection. This is an older picture. I added the solar since and several of the switches are up. Look for a generator transfer switch.

 

[jos51700]

Just wire an outlet to where the switch used to live. Per code, it should be a single receptacle, not a duplex receptacle. Then put a plug on the wire to the furnace. Then, plug it in.

If the power goes out, just unplug it and plug it into your generator (probably by heavy-duty extension cord, since the generator needs to be outside). There is no risk of back-feeding through the panel. IIRC code wants you to have a single outlet so you can't plug other stuff on the same circuit and risk popping the breaker.

Alternatively, you can do this so the switch kills the receptacle/outlet. Same net result. You just want a plug on your furnace to allow it to plug into the generator.

 

[4spdragtop]

Thanks, I'm not doing that.$$$$ I can safely turn off main power and feed furnace etc thru ext cords fed by a gen and inverter. I want to simply plug in power to furnace next time there's a power outage. It'll be safe but simple. Maybe not to code but safe.

 

[67Dart273]

Well Steve it would not cost you much, maybe 20 bucks to come off your J box and run an outlet, then just put a plug/ cord in the furnace.

As others have said you can also get in three in the J box and add a box beside it, with a 3 terminal switch (1 of the 2 in a three way) and use it to switch from a plug equipped cord or to the power from the box.

 

[MDchanic]

Just always keep in mind that, like tracer bullets, transformers work both ways.

The big transformer out on the telephone pole that converts 12,000 volts from the top of the pole to 220/110 volts to your house is more than happy to convert 220v from your generator into 12,000 volts and kill a lineman who is trying to restore your power, way down the road.

The transfer switch panel and the simple mechanical breaker lockout are both there to prevent this from happening. It is not advisable (or legal) to run your generator into your house wiring while your service disconnect (main breaker) has a chance of being accidentally switched on. Even a tiny padlock on your main breaker is a good idea if you don't have a whole system set up.

– Eric

 

[diymirage]

Just always keep in mind that, like tracer bullets, transformers work both ways.

The big transformer out on the telephone pole that converts 12,000 volts from the top of the pole to 220/110 volts to your house is more than happy to convert 220v from your generator into 12,000 volts and kill a lineman who is trying to restore your power, way down the road.

The transfer switch panel and the simple mechanical breaker lockout are both there to prevent this from happening. It is not advisable (or legal) to run your generator into your house wiring while your service disconnect (main breaker) has a chance of being accidentally switched on. Even a tiny padlock on your main breaker is a good idea if you don't have a whole system set up.

– Eric

This is exactly why I pulled permits when I installed my generator hook up to my house

Cheap piece of mind to know I will not be putting anyone else in danger

 

[LO23M8B]

If you are running the gen. you need to kill the main breaker on the house so it's safe for the linemen.

 

[tinman2]

Here you go. Simple. Furnace is completely seperated from main line. Check it out.

 

[ProjectBazza]

Just always keep in mind that, like tracer bullets, transformers work both ways.

The big transformer out on the telephone pole that converts 12,000 volts from the top of the pole to 220/110 volts to your house is more than happy to convert 220v from your generator into 12,000 volts and kill a lineman who is trying to restore your power, way down the road.

The transfer switch panel and the simple mechanical breaker lockout are both there to prevent this from happening. It is not advisable (or legal) to run your generator into your house wiring while your service disconnect (main breaker) has a chance of being accidentally switched on. Even a tiny padlock on your main breaker is a good idea if you don't have a whole system set up.

– Eric

Thank you for pointing this out, and beating me to to the punch! In the late 90’s we were without power for 6 days (I installed a whole house stand-by generator soon after), and the Utility Company fined all sorts of homeowners who were illegally back feeding the grid. Don’t know if any linemen were hurt, but my asshole neighbor got a pretty hefty fine after he was asked twice, and then warned several times, against doing that. Served him right, the prick!

 

[ProjectBazza]

Here you go. Simple. Furnace is completely seperated from main line. Check it out.

I like this! Don’t know if it meets NEC, but it’s safe!

 

[4spdragtop]

Thanks, that's what I was looking for.
The furnace breaker will be turned off, for safety measures.

Here you go. Simple. Furnace is completely seperated from main line. Check it out.

 

[jos51700]

Thanks, that's what I was looking for.
The furnace breaker will be turned off, for safety measures.

I didn't watch the vid but the rest I recommended CAN'T back feed the line. The generator is ONLY hooked to the furnace and whatever else you plug into it.
The back feed issue only exists when people try to connect the entire panel to a generator to feed the entire house. When my power is out, I am only concerned with keeping the pipes from freezing and the ice cream from melting