Cabling in wall cavity ?

[Rupert]

I am having a single story extension built and was wondering if it is acceptable to have the ring main cabling in the cavity to avoid having to channel out the walls ?

Graham

 

[Octopus]

Unacceptable.

A competent spark would tell you that.

 

[telectrix]

why channel, when the cables can be installed pre-plastering?

 

[Rupert]

Thanks for the quick responses.
We will be dot and dab plaster boarding so would normally channel out a bit to ensure that the plasterboard isn't impeded by the cabling.
Under the 17th edition what are the requirements for protecting the cable in this situation. The last electrician I had do some work for me said that we would have to either earth metal capping or fit an RCBO in the panel.

Graham

 

[Octopus]

All cables concealed in wall less than 50mm from the surface should be protected by an RCD or by 3mm capping.

Dot and dab is normally thicker than the cable.

So what has your sparky said?

 

[telectrix]

the cables will be well under the space behind the board. can be clipped, capped, oval tubed, but as murdoch says, unless capped with 3mm steel or in earthed metal conduit, must have RCD protection. your spark will know all this and advise you accordingly.

 

[Guitarist]

Thanks for the quick responses.
We will be dot and dab plaster boarding so would normally channel out a bit to ensure that the plasterboard isn't impeded by the cabling.
Under the 17th edition what are the requirements for protecting the cable in this situation. The last electrician I had do some work for me said that we would have to either earth metal capping or fit an RCBO in the panel.

Graham

As you are having an electrician carry out this work, why are you not speaking to him/her?

 

[telectrix]

i see a DIY (disaster in yonder) looming.

 

[Sintra]

Thanks for the quick responses.
We will be dot and dab plaster boarding so would normally channel out a bit to ensure that the plasterboard isn't impeded by the cabling.
Under the 17th edition what are the requirements for protecting the cable in this situation. The last electrician I had do some work for me said that we would have to either earth metal capping or fit an RCBO in the panel.

Graham

You are going to have to fit an RCBO regardless as the circuit is described by yourself as a "ring main"

 

[SirKit Breaker]

I will throw my two pennoth in as well.

All general purpose socket outlets must be RCD protected.

This means either the cable supplying the socket has to be RCD protected, or the socket outlet has to be one that incorporates an RCD. BUT, there are other requirements to consider regarding the application of the regs.

So as this is in the DIY forum, please accept my word that your circuits require RCD protection, end of.

Howard

 

[Phil L]

See above

 

[Rupert]

Thanks for the feedback. I am wondering what the significance is of me referring to a "ring main" making it a requirement that an RCBO be used as opposed to an RCD in a split panel that serves the circuit ?

 

[Octopus]

Get your sparky to explain it to you. It gets lost when trying to describe over the web

 

[Rupert]

I don't have an electrician on this job yet. I understand the difference between an RCD and an RCBO just wondered why there seems to be a preference to individual circuit RCBO's.
No sweat.
Thanks for the responses.

 

[telectrix]

I don't have an electrician on this job yet. I understand the difference between an RCD and an RCBO just wondered why there seems to be a preference to individual circuit RCBO's.
No sweat.
Thanks for the responses.

when he said fit rCBO, that's because it's a socket circuit. i assume he was thinking there may not currently be RCD protection. either will do. and just to be pedantic, it's a ring final circuit, not ring main. a ring main would be a distribution ring circuit.

 

[Rupert]

Thanks for the clarification. I am old school so ring main was the terminology I grew up with but I take the point. Ring final circuit it is from now on then.

 

[Guitarist]

I don't have an electrician on this job yet. I understand the difference between an RCD and an RCBO just wondered why there seems to be a preference to individual circuit RCBO's.
No sweat.
Thanks for the responses.

Are you planning on pulling cables yourself, and then hope to get a sparky to connect and sign it off?
If not, then it's easier just to get someone onboard now to explain what he/she will do and get you booked in.

 

[Badged01]

just wondered why there seems to be a preference to individual circuit RCBO's.

Better discrimination!

With an RCD (protecting multiple circuits) when it trips you loose all circuits on that RCD. With an RCBO protecting the one circuit, when it trips you loose just that circuit. RCBO's is a more expensive option so the RCD route is usual taken.

 

[Rupert]

Thanks again guys for the help.
The property had a full safety test when I moved in so I know I am starting from a sound position.
The electrical work required for my extension is in the form of additions to existing circuits so as such is not notifiable under Part P (2010). When I have further work carried out later that is notifiable, when completed, I will have the whole house retested.

 

[Octopus]

Thanks again guys for the help.
The property had a full safety test when I moved in so I know I am starting from a sound position.
The electrical work required for my extension is in the form of additions to existing circuits so as such is not notifiable under Part P (2010). When I have further work carried out later that is notifiable, when completed, I will have the whole house retested.

Having the house "retested" is different to it being notified.