Cable size and fuse selection

[Bradley6969]

Hi, looking for some advice on this, 3 phase board 25 SWA incoming feed from 60A BS88 fuses, looks like someone’s replaced the 100A main switch with a 125A 4 pole RCD is there anything wrong with that? I know 25 SWA can’t take 125A and overcurrent is 60A fuses, I never understood why haha
Thanks

 

[littlespark]

The 100A mainswitch and the 125A rcd are not over current protection devices, the 60A fuse is.
It’s just the current that can safely pass through them.

(same as a domestic light switch with 10A stamped on the back)