Questions about bathroom wiring

[Joe Shmoe]

Hi guys.

1)

A Bathroom Mirror Light that is wired into the existing lighting curcuit needs to be RCD protected. Does the presence of a TEST switch on my MCB mean this will suffice and the light can simply be wired into the existing circuit? Even if this is the case, on my MCB the lighting circuits are on the right hand side, which says its not protected by RCCB ? Will an seperate one need to be wired in in order to protect the mirror ?

2)

I recently fitted a whole new bathroom suite, but the one I pulled out did not have any earth grounding attached to the bath, sink etc. Do I need to get one put in? I notice the main stop-cock where the water mains enter the property is grounded, and all pipes entering/leaving my combi-boiler are also earthed to that pipe. Does this suffice ?

 

[RogerS]

Joe...you might like to post over on askthetrades.co.uk

Re your first point. I can't remember what the latest Regs say. There are specific zones and stuff inside each zone needs a specific rating. Having said that I think that your light does need to be protected by the RCCD side. The test button on your MCB only tests the MCB and the MCB is an over-current device (ie trips if you take excessive current). You passing current from your light fitting to earth won't be enough to trip an MCB. It will trip the RCCD.

But take care..you will need to ensure that you swap over both live and neutral to the RCCD side otherwise you will get a lot of nuisance tripping. You may well find that the neutral feeding your bathroom light also feeds other stuff that is over on the non-RCCD side....in which case you are probably stuffed.

Re bonding....there is mains bonding and supplementary bonding - which is what you are referring to re the bathroom....but there is a lot of rubbish talked about it...even by so-called electricians. I am not an expert and can give no advice on this. Other than use plastic water pipes and the question goes away! askthetrades are good