welding thickness on a wirefeed?

Now that I´ve been informed about the minimum thickness of sheets to weld, how about the other end, what would be the maximun thickness I can atempt with my 100 amp mig. At the moment it has a 0.035" fluxcore, but I also have a reel of 0.04" solid wire. It might of course(?) also be possible to get som thicker wire if that would help matters. BTW sometimes you experts talk about 110 volts or 220 volts machines. That doesnt tell me very much, how much amperage are we talking about here? In sweden housold electricity is 230 volt but it can also be phaseadded(?) to get 400 volts. (my water heater for instance runs on 400v. Henning