I know, I know I shouldn't do it, but I just built a cord to backfeed my house with my generator (120v 20A, 3550w).

One side plug is a 3 pin lock plug that goes into the generator and the other side is a plug that goes into my garage heater outlet (240v, 30A). The cord is a 12/3 gauge with 3 wires that O plug as per notice.

So I decided to try it today, disconnecting the main circuit breaker and all sub system circuit breakers. I started the generator and plugged it in. I then turned on the garage heater circuit breaker and the fridge and lights circuit breakers.

Didn't work... Any ideas why?

By the way, the garage heater circuit goes straight to the main panel through a thermostat (which was turned on to max).

  • 3
    Can you post a picture of the inside of your panel, along with labeling the breakers you called out in your post? There's a lot wrong with this, but the picture and labels are necessary to answer your question – Hari Ganti Dec 19 '18 at 0:26
  • My panel is all labelled in french which i understand.Do you think it could be that its maybe when i built the cord, i should have tied the hot on both pins (on the 240V plug) and neutral and groud together on the groud pin. – Jean denis Bordeneuve Dec 19 '18 at 0:58
  • 1
    Post the photo and add translations (either by scribbling them on the photo, or separately as part of the post). There's lots of stuff wrong with what you did, most likely, but we can get you on a path to being able to plug your generator in safely next time it's called for if we know what's going on here. – ThreePhaseEel Dec 19 '18 at 1:00
  • Also, does your generator have a 4 prong receptacle of any sort on it? – ThreePhaseEel Dec 19 '18 at 1:00
  • 1
    You would never tie the green and white together. – Harper Dec 19 '18 at 5:25

Before any of the electricians condemn this fix let me say that even though is is "wrong" it does work. My son used this trick a few years ago and it kept him warm in the winter for a few days, until the power company could fix the downed wires. If you have a 120 volt receptacle that you could plug into, why not use that and utilize 1/2 of the circuits. Pick the right one and you could have emergency heat and even keep your beer cold. Just make sure that you turn off the breaker for the incoming power.

  • You may not like what I wrote and it may break all codes, but it works! – d.george Dec 19 '18 at 14:54
  • Ok i might have to do that. The reason for going into a 220v receptacle was to get the 2 phases fed because the circuits i need (lights, fridge...) are mixed betwen the 2 phases. – Jean denis Bordeneuve Dec 19 '18 at 16:00
  • If you have an electrician friend ask him if he/she has a better idea or can help. – d.george Dec 20 '18 at 12:02
  • Ok so i used a 120v receptacle and plug and it works but onlu on phase 1. Still can't figure why it didn't work on with the 220v receptacle and plug. Maybe i should separate my hot wire in 2 and tied half of it to both prong ? What do you guy think ? – Jean denis Bordeneuve Dec 20 '18 at 22:32

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