wet room bonding

[cam123]

I'm having a wetroom installed as an en-suite to an upstairs bathroom, are there any Part P's out there to advise as to how the earth bonding for lights/pipes etc should be carried out ?

My builder is saying that it should be 4.5mm earth wire, linked to everything and taken back to the "main water pipe". But i have seen it written on here that often the earth should be wired into a socket for a special zone, and also that earth should be taken back to the MET but never that it should go to the (already earthed) water pipe.

Also, how should the shaver point and extractor be earthed?

I will have a Part P sign this off, but i'd be grateful of some info in the mean time please, to save changing incorrectly done work.

 

[Spark123]

You'd be better getting your "part p" electrician to advise from the start - if all the circuits of the location are protected by RCD and all the extraneous pipework is effectively bonded back to the MET supplementary equipotential bonding may be omitted under the 17th edn regs.

 

[cam123]

We don't have rcds right now but we will be replacing the consumer unit in June and so will be cracking from then on. The question then becomes what do we do in the mean time?

What do you mean by extraneous pipework?

 

[RF Lighting]

Extraneous pipework is any metallic pipework which can introduce an earth potential into your equipotential zone.

As for the bonding, you must install bonding between every metallic service entering the bathroom, and the CPC of every circuit entering the bathroom.

This must be a minimum of 4.0mm² if it is not mechanically protected.

You will not be able to install any additional wiring into your bathroom without RCDs being installed. (except for supplementary bonding)

 

[Spark123]

All circuits installed in shower rooms need to be RCD protected to comply with the regs so if there is no RCD it won't comply with the regs.
Extraneous pipework is any pipework which can introduce a potential (voltage) into the area.
Best bet is to have an electrician do the installation work for you tbh, this work will probably be notifiable to your local authority building control under part p of the building regs.

 

[Taylortwocities]

We don't have rcds right now but we will be replacing the consumer unit in June and so will be cracking from then on.

The RCD must be in place at the time the work is done, not at some time in the future. Your electrician could install a temporary one until the CU is changed, but the work must comply with the relavent standards - this applies to all electrical installations - even temporary ones.


To reinforce the other answers:
The work to be done is notifiable.
You need to notify the local authority or use a registered electrician to do it.
Also, ignore the builder - he has a vested interest in getting the job done and wont care about your safety.
IMHO he doesnt know what he is talking about. There is no standard cable size of 4.5mm².

 

[cam123]

I've had building control out to see it, but the guy seemed to just not want to get involved with anything electrical when i was asking questions, the attitude basically being "get your electrician to sort it all out".

Will building regs not sign off electrical stuff themselves? Do they absolutely have to have an Part P's certificate to do this?

I'm a bit stuck now because i wasn't expecting to have to change the consumer unit yet and haven't budgeted to do all the big electrical work in the house at this point. Is it not reasonable on a practical level to bond everything according to what was necessary before the rcb regs and leave it like that for two months until i can afford to have the consumer unit changed?

Even with a rcb / new consumer unit, i still need to bond the extraneous pipe work yes?

Should 4mm earth be used for the pipes and lights then if 4.5mm doesn't exist?

 

[scarypants]

If building controls have been to see you, does that mean it's been notified?
Building controls will get an independant in to inspect and test.
Then give you a cert saying complies with part p of building regs. (Providing it does) This not an electrical cert
4.0mm cable should be used for supp bonding if not mechanically protected, a smaller csa can be used if mechanically protected as already stated 4.5 does not exist!

You should get an electrician in asap

 

[cam123]

Oh yes, it's been notified.

Do the council get you to pay for this independent electrician?

So why do people talk of getting an electrician in to issue the certificate if it is the council that sort that out? Or is it that there are two ways of going about getting it signed off?

For the layman, employing certain builders is an absolute minefield!

 

[ban-all-sheds]

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http://www.diynot.com/wiki/electrics:part-p
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[stargazer]

Do the council get you to pay for this independent electrician?

They shouldn't, but there have been many cases where public authorities exercising powers have failed to understand the limit, scope or effect of the powers under which they act.

Have a look at the thread below.

http://www.diynot.com/forums/viewtopic.php?t=171390

 

[scarypants]

cam123
The main reasons for getting a qualified electricain in is as follows,
They can sign their own work off without controls being involved,
they can give you guidance on the best methods that should be used for your particular installation,
it gets done quicker, gets done right and everyone is safe!
To name a few!