That 3 for 3-phase must be a typo! For just an 11KW oven, it's probably your choice of 208V 1-Ph or 240V 1-Ph. But I wouldn't guess; if no manual or diagram is available, can you call the manufacturer of the oven for clarity?
Some commercial ranges like the Garland ones say single or three phase on the talley plate. They give you all the different ways they wire their stoves depending on what you order. Basically one talley plate for every stove. You have to specify how you want it wired so it is compatible with your supply. In your case it seems to be wired 3 wire 240 or 208V because of the neutral.
I guess I assume too much and would normally think that he knows where the leads are going before he connects them up.
If it has a cord see where the wires are going. Make sure the cord has a bond. By following the white lead you determine that it is a neutral hook the white wire to the identified conductor. You would figure there would be a diagram on the stove for you.
If you are unsure about these connections find more info on the range, get in contact with a distributor, don't rely on forums for this info, you don't want to do any costly mistakes.
ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals