Bathroom Wiring

[Naz1977]

I am installing a new bathroom ( Well moving my bathroom from one side to the other side of the house).

So need to run some new cables from my CU to the new bathroom.

Does this sound right:

1) 9.8Kw Electric Shower, run 10mm cable from CU to the shower. However as it is an old CU at the moment, need to install a new Shower RCD next to the CU. This will run to an isolator switch which will be mounted outside the bathroom.

2) 1.0mm cable for the lighting to its own dedicated MCB.

3) 1.5mm cable for the electric mirror, shaver socket and bathroom fan ( Fan will have another isolator switch outside the bathroom) again these will go to one dedicated MCB

Does this sound about right?

 

[EFLImpudence]

1. Yes. 6mm² cable would be adequate if there are no adverse factors affecting it.

2. Yes. New circuits are notifiable to the Local Authority. New concealed, unprotected cable runs should also be RCD protected.
3. Why? They may as well be on the same circuit as the light.

2 & 3 could probably be added to the existing lighting circuit.


ALL circuits of a new bathroom must be RCD protected.

 

[Taylortwocities]

As EFLI says. All those circuits must have RCD protection.
All that work is notifiable to LABC.

My advice: get a registered electrician to change your CU to a new one. That will provide the required RCD protection. He also to do the bathroom electrics. He also will provide certification and do notification to LABC.

 

[Naz1977]

Thank you for the replies.

as for #2 and #3, I like to keep circuits separate if I can so that I can isolate individually if I ever have to work on it. That's why I wanted a separate circuit for the lighting and the shaver sockets.

As for a new CU, yes, I will have to replace it as I will be adding an extension to the house and might as well do the electrics at the same time. It is a 1930s bungalow with probably about the 1930s electric cables at the moment.

I will start a new thread for that side.

I will get a leccy to do the testing, however to save the costs, I am planning on running the cables and doing the channeling and ... for the cables.

 

[EFLImpudence]

as for #2 and #3, I like to keep circuits separate if I can so that I can isolate individually if I ever have to work on it. That's why I wanted a separate circuit for the lighting and the shaver sockets.

For the sake of an inspection lamp that is totally pointless - unless you mean you might want to have a shave while working on the lights..

I will get a leccy to do the testing, however to save the costs, I am planning on running the cables and doing the channeling and ... for the cables.

See new thread.

 

[flameport]

Does this sound about right?

No.

 

[Naz1977]

ALL circuits of a new bathroom must be RCD protected.

ok, so does it mean I need to have a separate :

Bathroom lighting circuit : Lights/Shaver and Fan
Bathroom Shower: Electric shower

Both on RCDs?

or can the lighting be fed from the main lighting feed to the rest of the property?

 

[Taylortwocities]

ALL electricity circuits within the bathroom must be RCD protected
Any wiring in walls less than 50mm from the surface must be RCD protected.

Time for you to read BS7671

Better, as advised above

get a registered electrician

 

[Naz1977]

ok, thanks.

So the best option is to change the MCB for the lighting with the RCD and then run the lighting for the bathroom from the main lighting circuit.This was it is RCD protected, rather than run a whole new circuit for the lighting and fan?

 

[Taylortwocities]

You can't change a MCB for an RCD, they do different jobs.
You could change the MCB for an RCBO, but in every case, the work you are thinking about is NOTIFIABLE

get a registered electrician

 

[Naz1977]

That's fine as I am currently doing some building work and a building inspector is inspecting all the work. So he will do that and I will obviously pay the £150 fee for it.

 

[ban-all-sheds]

So the best option is to change the MCB for the lighting with the RCD and then run the lighting for the bathroom from the main lighting circuit.This was it is RCD protected, rather than run a whole new circuit for the lighting and fan?

No - the best option is that you have the work done by someone who actually knows what they are doing.

 

[ban-all-sheds]

That's fine as I am currently doing some building work and a building inspector is inspecting all the work. So he will do that and I will obviously pay the £150 fee for it.

They inspect to confirm that you have complied with all of the relevant regulations. But before then, when you apply, you have to tell them how you plan to ensure that you will comply.

So what did you tell them would be the way you'd ensure compliance with part P?

 

[Naz1977]

I have told them that an electrician will inspect all the wiring and provide necessary certs to confirm compliance with all necessary regulations.

There is an electrician who will test the circuit, but in order to save him time and effort, I wanted to go through things as I understood it before he came across to go through my requirements. However it seems my understanding was wrong on how to wire the bathroom.

For now, until I either decide to replace the whole CU now or later, I will install a shower CU for the single electric shower in the house, and run a new circuit for the fan/lights/shaver through my existing CU with a rcbo.