Just a quick question, need to add some lighting to an existing circuit, during Pre tests found zs value exceeds maximum permitted, it is a long circuit to be fair around 200m, it is 1.5mm twin. It is on a 10amp type b at the minute cant drop it to a 6A due to the amount of fittings on the circuit. There is a sub board half way round the building in the lift motor room I have the choice of re feeding the second half from this board which is possible but the other problem is it has a 110v emergency back up supply to each fitting which is the same length. Would it be deemed acceptable to pick up a 4mm earth from the sub board half way round into the circuit to bring the zs down? I really can't think of another way around this unless anyone has an idea?
