Can somebody help me please? I've taken the panels off my bathroom walls and found that there is no supplementary bonding on the cold & hot water feeds to shower, sink, bath or toilet! I understand from previous questions placed on the forum that this has to be done in 4mm single core but i'm a bit puzzled over where I need to pick the earth up from! My first question is... do I have to run this 4mm cable back to the earth block on the consumer unit or can I run it to the earth terminal in my shower unit which is fed by 10mm twin & earth? Second question... can this be extened to the hot water tank in the airing cupborad next to the bathroom or does this need to be seperated? At present the earth block only supplies bonding to the kitchen sink & incoming water pipe from the mains supply.