DIY- Generator to house hookup/ Need confirmation on my plan

Alan MAL · Feb 12, 2022

Greetings, I would like to preface my post by stating I'm well aware of the legalities and danger that are present with this configuration. This topic pertains to backfeeding my home with a portable generator during an emergency power outage. I currently have a L14-30R 120v welding receptacle in my garage. I have a small welder that I use for diy projects. Cable is 8/2 mc cable energized from a single pole 30a breaker in my panel. Is it feasible to add a 30a double pole breaker in my main panel, disconnect wires from 30a single pole and transfer neutral from buss bar and hot lead to the double pole to energize both buss bars in panel? I know that 220v/240v does not need a neutral so the "white" nuetral can be used for a 120v hot leg. I surely realize the importance of shutting off main and all circuit breakers before hooking up generator. I care about the lineman!! Current 30a circuit is also properly grounded. What is my wattage capacity for this setup? 6500? Lastly I do know the proper way of doing this with transfer switch, etc. Funds are limited outside of generator purchase. Thoughts on my plan?
Thanks

partplonker · Feb 12, 2022

My thought - install a changeover switch. I don't know if they're really expensive in the US, but here you can get a single phase break-before-make changeover switch for under £100

In my opinion it is not worth saving that money to injure yourself, someone else or damage your installation if you cock it up.

Alan MAL · Feb 12, 2022

partplonker said:
My thought - install a changeover switch. I don't know if they're really expensive in the US, but here you can get a single phase break-before-make changeover switch for under £100

In my opinion it is not worth saving that money to injure yourself, someone else or damage your installation if you cock it up.

Agreed. Transfer Switch in my area are approx $450 US for a 6 circuit unit.
Thanks Partplonker.

Megawatt · Feb 12, 2022

Alan MAL said:
Greetings, I would like to preface my post by stating I'm well aware of the legalities and danger that are present with this configuration. This topic pertains to backfeeding my home with a portable generator during an emergency power outage. I currently have a L14-30R 120v welding receptacle in my garage. I have a small welder that I use for diy projects. Cable is 8/2 mc cable energized from a single pole 30a breaker in my panel. Is it feasible to add a 30a double pole breaker in my main panel, disconnect wires from 30a single pole and transfer neutral from buss bar and hot lead to the double pole to energize both buss bars in panel? I know that 220v/240v does not need a neutral so the "white" nuetral can be used for a 120v hot leg. I surely realize the importance of shutting off main and all circuit breakers before hooking up generator. I care about the lineman!! Current 30a circuit is also properly grounded. What is my wattage capacity for this setup? 6500? Lastly I do know the proper way of doing this with transfer switch, etc. Funds are limited outside of generator purchase. Thoughts on my plan?
Thanks

I done the math on your 6500 watt generator which come out to 27.01 amps at 240 vac. My friend the best I can understand is that do not use the neutral for anything than it’s designed for. Add your 30 amp double pole breaker and install a 4 wire system from your generator which is 2 hots 1 neutral and 1 equipment ground Good luck and hope this helps.

Alan MAL · Feb 12, 2022

Megawatt said:
I done the math on your 6500 watt generator which come out to 27.01 amps at 240 vac. My friend the best I can understand is that do not use the neutral for anything than it’s designed for. Add your 30 amp double pole breaker and install a 4 wire system from your generator which is 2 hots 1 neutral and 1 equipment ground Good luck and hope this helps.

I agree. Thank you. We will start old school with extension cords for the near future then I'll upgrade to an dedicated circuit .

Lucien Nunes · Feb 12, 2022

transfer neutral from buss bar and hot lead to the double pole to energize both buss bars in panel? I know that 220v/240v does not need a neutral so the "white" nuetral can be used for a 120v hot leg.

No. Both hots and the neutral must be connected otherwise the two groups of 120V circuits on the two busses will be connected in series. They would receive various uncontrollable voltages from zero to 240V and the appliances and lamps could be burned out.

For some panels you can get a mechanical interlock which only allows the generator breaker to be turned on if the main switch is off and vice versa. If that is available for your panel it would save the cost of the transfer switch.

Alan MAL · Feb 12, 2022

Lucien Nunes said:
No. Both hots and the neutral must be connected otherwise the two groups of 120V circuits on the two busses will be connected in series. They would receive various uncontrollable voltages from zero to 240V and the appliances and lamps could be burned out.

For some panels you can get a mechanical interlock which only allows the generator breaker to be turned on if the main switch is off and vice versa. If that is available for your panel it would save the cost of the transfer switch.

Lucien Nunes, I completely understand now that my plan would have ended in a bad way when energized. I have investigated the metal plates type interlock. Unfortunately when looking at my panel the Electricians who wired the house did it "too clean" ( not a bad thing) and didn't leave any tail length on conductors within the panel to enable me to relocate breakers. Without that as you know I'm unable to clear up top location for the gen breaker interlock. I'll have to do more investigating and see what I can do. Thank you for your great input.