rcd bathrooms

21 Mar 2007
Reaction score
United Kingdom
if i wish to add rcd protection to my bathroom lighting using a rcd fcu, where in the circuit would i put the fcu
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It would be much better to put an RCBO in the CU. If that is not an option then put the RCD FCU (outside the bathroom) before the cable from the lighting circuit goes into any of the switches or light fittings (not sure if you have an extract fan, mirror demisters etc?)
What is the work you are looking to carry out? I'm assuming your looking to do some alterations to the lighting circuit in the bathroom or does the work extend to other parts of the lighting circuit? Do you have more then 1 lighting circuit in your house and if so how many and what is on each of them?
It would depend what you are protecting and where your cables run.
Any automatic disconnection device can operate when we least expect it and really a basic risk assessment as to what may happen if it trips.

For example if when you should lose all upstairs lighting supply an emergency light will light then you may feed you may as well protect the whole of upstairs lighting.

However if when you lose it a dangerous situation is created then you may want only the bathroom light protected.

However as time goes on it is likely you will need to include all lighting on a RCD because of 50mm rules. So may be better to fit an emergency lamp.

Only you know what your house is like. You must consider what would be best in your house.
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its to protect bathroom light and extractor only, but if i were to take light feed into rcd then onto light fitting i understand everything from there will be rcd protected (i mean any other lights onward from bathroom)

how assuming the rcd fcu is the only option i wish to take and only want bath light and extractor on it where would it go in circ?

feed in from last light...rcd...ceiling rose...switch.....extractor
Just loop in and out to the supply side of the RCD, then our output side is the perm L&N to the bathroom light and fna via the switch, don't forget the fan isolator!!

This way it's only the bathroom lights that are being RCD protected... a RCD or RCBO for the whole circuit would be the best option though!!

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