Some advice on good practice please. I need to replace the 6kW shower that my father fitted about 30 years ago, and I'd rather like an RCD to protect my hide when using it. I looked in the meter cupboard, and didn't like what I saw. There's a 100A company fuse, an 80A meter, an 80A old black bakelite Wylex 8 way CU with 80A switch and cartridge fuses, and what look like 60A cables from the company fuse to the meter and 80A from the meter to the CU. I guess I should get the company to replace their cables. Should I expect a new meter too? I see this estimable company selling a Volex 80A RCD at a nice price. If I had an 80A fuse, I could wire the meter tails to the RCD and thence to the CU and have everything protected. However with electric cooker, shower and if the gas is off 3kW fire and 3kW immersion heater, 80A looks marginal, and the company fuse is 100A. Should I just shell out for a 100A RCD, significantly more expensive? The alternative is a new 8way CU with 100A switch and MCBs. Here's where the fun starts - I see most come with a smaller RCD rating than 100A. Is the trick is to split the circuits, with some outside the RCD's protection and others within, or do I just say "diversity" and stand clear? What's normal practice? Thanks in advance.