In theory, yes you can increase the CSA of the cable which will allow a higher design current to be drawn. You do need to give consideration to the pitfalls of doing this. If your supply from the DNO is 100Amps on 35mm CSA tails protected by a 100amp fuse, why isint the whole house wired in 35mm cable? .............Cost, Terminating cables in accessories etc, also if there is any problem with the cabling like a dead short then the main fuse will blow and the whole house will be without power.
Therfore if you devide the circuits up, you can use smaller CSA cables, which are protected by smaller rated protective devices which will hopefully confine any problems to that circuit.