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Rcd regs in bathroom need an earth or not?

Hello, I am having a new bathroom fitted and want a extractor fan being fitted as the room has not got one at present. The bathroom fitter has said this would be very expensive as the current lighting in the bathroom is not earth protected and fitting the extractor fan would need to be RCD protected, understandably so - but doing so needs an earth and the house needs to be re-wired so that the fan can be signed off against regs even though the fan does not require an earth connection as its double insulated and the wiring diagram states it "MUST NOT BE FITTED TO EARTH" why does an earth need to be wired through the house for an item that does not need to be earthed?

4 Answers from MyBuilder Electricians

Best Answer

Electrics is not my area however, I have worked in environments before where the team needed to install ext. fans, sealed light units, down flow heaters etc into adapted bathrooms of older properties, for disabled persons. I do recall the specifications required a new 'split board' off of the existing house wiring. Thus, the new split board would serve the newly installed items, and meant the rest of the house wasn't touched.

Not sure if that helps you or not, the Sparkys on this forum will advise further.

Many Thanks, Jason.


Answered 16th Oct 2015

Bathrooms under part P of the building regs are considered 'special locations', therefore any electrical work in them must be notified to building control at your local authority.

That is building regulation legislation as it stands, and there are no exceptions for any electrical work in bathrooms.

A registered electrician will be able to do that for you as a matter of routine, as they should be able to self certify there work if they are on the competent persons register. (Google competent persons register to find out if they are registered and able to do that).

Under latest writing regulations, there is no specific need to have extraneous metalwork earth bonded in a bathroom, but water and gas incoming pipes must be bonded to the consumer unit within 60cm after the meter (there are some exceptions eg if all plastic supply etc).
However, all bathroom services must be protected by a 30mA RCD.

All new or additions including a new extractor fan, must conform to these requirements, whether out not it needs earth.

Whether it needs earth or not depends on what the manufacturer says. So if it's double insulated it won't.

Either way, all the above rules need to be followed. Draconian? It sounds it, but the rules are designed to perfect people from electrocution, and a bathroom is (electrivally) a high risk environment.


Answered 17th Oct 2015

Why not just get an electrician in to get it all done right? Too long an answer to put on here to your question tbh. Just bear in mind any electrical work in a bathroom has to be notified to Building control. This can be done by a part p spark. If you do the work you have to notify them yourself before you start pay the fee to them etc etc. If you do neither you risk a fine of around £5000 I believe. So why risk your safety by not getting a spark in to do it all right?


Answered 17th Oct 2015

My concern would be the age of the wiring if there is no CPC (earth) on your lighting circuit.

This type of installation is generally pre 1960s and as such there is a high likelihood that other 'faults'/non-compliances on the installation exist (thinking absent or else undersized main bonding, etc...)

If your bathroom fitter is not an electrician, my best advice would be to employ a professional, registered electrician to check your installation over before giving you any advice with regards your bathroom extractor fan.

It is worth noting that if you have any class 1 (IE: metallic) light switches or fittings on this circuit without a CPC then they are considered to be potentially dangerous as under fault conditions could be live. Please get some advice from a local, registered electrician.


Answered 21st Oct 2015

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