earth to neutral short

markthebuilder · Posted: Mon Sep 11, 2006 11:59 am Post Subject: earth to neutral short

I checked granneys 100a/80a 30ma split load consumer unit to see if it could take additional mcb for Shower.Noted Cooker circut wasn't RCD protected so shifted mcb & neutral to that side. But 80amp RCD wouldnt reset so took out wires again and tested with multimeter which showed a short neutral to earth.
I put back as was with Cooker not RCD protected and all work ok but I have now turned off cooker at mcb as don't want a dangerouse situation
Is neutral earth fault acceptabel?
should cooker be RCD protected?
What is maximum load on an RCD/ incomer ? eg 4x32a +1x45 =173a

JohnD · Posted: Mon Sep 11, 2006 12:19 pm Post Subject:

Cookers are not usually put on the RCD because (1) they are not portable and are seldom caried outside and used in the rain (2) the oven elements, in particular, tend to leak to earth when they get old. There is an annoying problem with some Cooker Control Units having a 13A socket on them. Who knows how that socket might be used?

IF it is just N-E not P-E it is not generally considered dangerous but you might think about having it tested.

Design load on an RCD can be calculated using diversity; BUT remember that the installation will have a suppliers fuse at 100A or 80A usually, so the CU will not be able to draw more than that for long.

Most RCDs are rated at 80A or 100A; some are only 63A. Unless you have an electric shower and some electric heaters (or a cooker) going through the RCD you will probably not reach that.