I want to change a fuse board in my dads bungaow, its a simple change from a 6way old rewireable fuse board (2 ring circuits / 2 lighting circuits / 1 circuit to outside shed / 1 circuit to electric cooker, what i want to know is how legal is it to remove the cutout fuse before i take the tails out of the old fuse board and what size do the new tails need to be and lengh?