Bloody hell guys
The fuse is not to protect the welder, it's to protect your house wiring. If you pull more current than the wiring is capable of handling it will heat up and potentially break down the insulation. The max permissable current is 13 amps, any more than that and the wiring and socket is being over worked. I don't want to sound over dramatic but I have seen a major house fire as a result of an overloaded socket - it aint pretty. If your welder requires more than 13 amps have a proper circuit put in, it aint worth the risk.
Enoch.