breakers

Hey guys just joined the forum because I'm having this issue. Been a few days now and my RCD trips and 2 breakers stop it from turning it on again. Only when I leave these 2 breakers off, does the rcd goes back on. The 2 breakers are for the kitchen. So all sockets incl fridge, washing...

I noticed today that the mains switch in our CU is a single pole (63a fused) switch (only Live attached) - when did they do away with Double Pole mains switch and wouldnt Double Pole be safer than single pole so that when you turn off the main switch in the CU it kills both live and the neutral...