I have a couple of questions about hooking up a generator to a manual transfer switch and I'm really hoping somebody with knowledge can help guide me here. The idea is I will have an exterior weather-proof plug that I can plug the generator directly into outside, and have that plug wired to a transfer switch inside that is wired to my main panel (only the circuits I plan to use if the power goes out - probably 10 circuits). The specs of my generator that I think are relevant are below. I think my questions will be pretty basic for somebody experienced with this.

  • 10,000 watt peek surge output, 8000 rated
  • 15HP, 420cc, Air Cooled, OHV, 4 stroke engine (horizontal shaft)
  • Regulator: Automatic Voltage Regulator
  • Low oil shutoff system
  • 4 standard outlets. Fully protected 110V.
  • 1 twist-lock outlet. 240V 30amp outlet, NEMA L14-30R
  • 1 twist-lock outlet. 120V 30amp outlet, NEMA L5-30R
  • 1 DC outlet, 12V, 8.3amp. Convenient for charging any 12V battery
  • Max Current 60Amp @ 120V, 30Amp @ 240V

My main house entrance panel is 200AMP.

My questions are:

  1. Would I only want to plug into the 240V outlet and run that cord to an exterior 240V plug and then wire that to the transfer switch? Would that power everything I need? I don't plan to ever run the dryer during a power outage (will dry clothes near the wood stove). Is there anything else that would use 240V? If I am not running anything in my house that is 240V is it better to run from the 120V plug on the generator?

  2. When the last listed spec above (Max Current 60Amp @ 120V, 30Amp @ 240V) says Max Current 30Amp @240V, this means that I can draw a maximum of 30 amps simultaneously with the 240V output?

  3. Why does it say "Max Current 60Amp @ 120V" when just above that it says "1 twist-lock outlet. 120V 30amp outlet, NEMA L5-30R"? Is the 120V outlet 30 amp or 60 amp?

  4. Also, do I need a 60 amp transfer switch to get the maximum out of this generator or 30 amp? or higher?

I know it's a lot of questions but hopefully somebody can answer them.

  • 4
    Based on the type of questions you are asking, I would not recommend you attempt this project yourself. This is going to require a licensed electrician to complete. Based on their evaluation of your needs, they will provide the proper answers.
    – longneck
    Dec 22, 2014 at 21:14
  • To answer your questions.
    – Some Guy
    Mar 18, 2015 at 21:16

2 Answers 2


I will join longneck, you need to give to give this one to a pro.

If you do not understand about back-feeding a circuit, already, it is too easy to kill someone. I say this without exaggeration.

The biggest problem with running a generator with a transfer switch is that you have to wire it into your main panel.

For basic protection of life, (as well as the law,) it must NOT be possible to have your generator and the power to your house on the same wire, at the same time.

This is not a case of, just for a few seconds, or I would not do that, or I will triple check a written list.

It must not be possible under mechanically, electrically, on with quantum physics.

The reason is that if you put power on the 'dead' wires to your house, it is possible to kill someone a mile away, or more.

Emergency workers expect down lines to be dead. Yes, they do check first, but that does not mean that the situation can not change while they are working on them.

Transformers work backwards, low voltage at your generator (240) quickly becomes high voltage (thousands).

And sometimes people, and pets, or cars, just do not even see a fallen power line.

This is a case of some money to a pro vs life.


While I am no expert it seems logical that you can only use a 240v capable generator as both wires must be hot to power both sides of your home panel through a double pole breaker This is so Both Sides of your panel are energized, therefore giving 110 to all breakers.

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