I am in the process of going unvented. I have to use immersion heaters, and the new cylinder has two. I have one feed to the existing immersion. It is on 2.5mm2 T&E and connects to a 32A MCB on the CU. I'm adding a DP isolating switch in the cylinder cupboard. Will that be complaint for one of the immersion heaters?
To fully install the cylinder (ie the second immersion), I plan ask an electrician to either
(1) run an additional 2.5mm2 T&E cable back to the CU, connect it to the existing 32A immersion heater MCB at the CU. So the MCB protects two separate cables and the 2.5 T&E is within its capacities.
Or
(2) run a new 6mm2 T&E cable back to the CU, connect to the existing MCB and in the cylinder cupboard, split the feed to two DP isolators, one for each immersion and its timer.
I'd be grateful for advice - are both approaches compliant? Is one better than the other? The amount of work will be similar.
