Given that neither of you knows the answer, it is an indication that your knowledge of the electrical system is far too limited for you to be doing this yourself. And this forum cannot supply all the tutoring needed. Hire a pro.

What, hire a pro to answer whether it's 240 or 120 ...you have got to be kidding me !!.. I'm not wiring his house .. I just asked a question. And if you don't know just say so..

So what are the requirements? Is the well pump 120 or 240? (some pumps are 240v, did you check?)

If he already has the 10KW unit, that is way overkill for the few things you listed.

Have you looked at the interlock to see that is a 240v breaker? I don't understand the "pick 120 or 240" question.

This post was edited by jreagan on Tue, Jul 15, 14 at 17:26

I assume this is one of those generators that allow you to put 240v out of one outlet or 120v out of another (if not the same). The generator has two windings, each producing 120v. The switch allows you to 'change the phase' of one of the windings so that they are both in parallel, giving you double the amperage for the 120v socket.

As to his house, it depends on how the interlock and exterior socket was wired. It should have been 240v to be useful, that is, capable to provide power to the whole house. It would also be nice to know the wire size to see if you can actually pump 10kw through it without melting the wiring. The size of the breaker would give you a hint. A 10kw generator can supply a little over 40 amps at full load.