The Survival Podcast Forum

Survivalism & Self Sufficiency Topics => Emergency Preparations => Topic started by: evh on September 02, 2018, 04:21:20 PM

Title: Furnace / Generator Hack
Post by: evh on September 02, 2018, 04:21:20 PM
I thought I would share the furnace hack I did to accommodate my generator.  I watched a number of YouTube videos and I think there are no safety issues with this, but I welcome any comments. 

So my background is I live in Michigan and we experience a small number of outages where I live (roughly 3 – 4 per year).  Usually they last < 12 hours but we had one go for 3 days a few years back.   Not that is a big of a deal in the summer but when it is 20 degrees outside the house gets really cold!

I few years back I bought a 2,000 watt inverter.  I use extension cords and can keep things running as I need them in the house with the exception of my natural gas furnace.  It is hard wired.  I checked and found that the inverter would run it.  So I am sharing the < $15 easy modification I made so it would.

It must be code where I live (maybe all over) that the furnaces have a shutoff for the furnace on it  (rather than just throwing a breaker).  So mounted on my furnace is a basic switch and screw in fuse setup. See the first link below.  I wondered if they made the same setup but instead of a switch, it was plug.   See the second link, they do. Using this instead of a the switch allow me to wire a 3 prong plug in my furnace wiring and plug it in. 

If someone needed to work on the furnace, they would just pull the plug.  However, If I wanted to run the furnace with the inverter, I could simply unplug it from the receptacle and plug it into my inverter powered extension cord.

Well that is what I did and it works great.  I lost power in January 2017 and ran the furnace for about 8 hours.  No issues.  Again, I thought I would share.

Title: Re: Furnace / Generator Hack
Post by: Carl on September 03, 2018, 04:46:57 PM
  Looks like a great way to prevent back feeding of the grid and power-workers
Title: Re: Furnace / Generator Hack
Post by: evh on September 04, 2018, 07:09:52 AM
Yes, it looked to me like an inexpensive and safe solution.  I was also happy to see my 2,000 Watt inverter handled it with no problem.
Title: Re: Furnace / Generator Hack
Post by: sharpshooterofky on October 03, 2018, 08:56:41 AM
Is it really that simple?  I'd be interested in seeing some pics.  I was thinking the same thing (or close to it), we have an extra shutoff switch out by the furnace, and I was thinking why couldn't I just plug in there?   The electrician I talked to thought I was nuts (which is true) but I kept thinking that this would solve my heat problem.  Thanks for I just have to figure out the specifics and I'm in business.
Title: Re: Furnace / Generator Hack
Post by: evh on October 04, 2018, 06:53:05 AM
Picture A shows what was on my 120 volt Natural Gas Furnace.  Power comes in through the breaker, goes through the fuse and is wired to the switch.  Internally, the wires from my furnace (hot, neutral and ground) are connected to the other side of the switch.  So if someone needs to work on the furnace, they simply flick the switch and power is cut off to the furnace and they can work on it safely.

Picture B shows what I replaced it with.  Power comes in through the breaker and goes through the fuse just as before.  However it terminates at the female plug receptacle that is part of the new box I mounted.  I then took the wires from my furnace (hot, neutral and ground) and connected them to the 3 prong male plug you see coming out of the side of the box.  To clarify, the furnace wiring is not connected in any way internally in the box you see, it was just convenient to have the 3 prong plug come out of the side of the new box I installed.

So when power fails, I simply run an extension cord from my 2,000 watt generator / inverter to the furnace.  Unplug the plug you see in picture B and plug it into the extension cord.  I now have power from the inverter feeding the furnace. So there is a physical disconnect from my inverter to the wiring coming from my breaker so I won’t accidently back feed generator power into my house and the power company.

Your setup/conversion might actually be easier depending on what your “Shutoff Switch” setup looks like.  You may simply need to replace it with both a male and female extension cord ends.  See picture C.  Make sense? 

Note, picture C shows plug ends with the wiring still attached.  You may just need the male and female connectors.  Make sure whatever you use matches the size/amps of what your furnace requires.
Let me know if you have any questions or post a photo of your “Shutoff Switch” setup.

Picture A (

Picture B (

Picture C (