Extending my lights and sockets into my new house extention

[washerman]

Hi everyone this is my first post so be kind to me..
I have just built a two bedroom extension to my 1985 house and need some advice please.
I will be having the walls dot and dabbed to hold the plaster board on and need to know some of the rules governing how to install the cabling in the two new bed rooms and the three new rooms down stairs so here goes with all my questions:

1.
can I just extend the existing ring main in the existing 3 bedrooms into the new 2 bedrooms? and if so what depth and what size hole do I need to make in the new joyce which I need to drill through?

2.
Do I need some metal covering over the cable and behind the plaster board when I come up the wall in the new bedrooms?

3.
Can I just extend the lighting circuit from the other bedrooms into the new bedrooms?

4.
Are you aloud to run 2.5 cables for a ring main horizonlaly around a room plus is there a limit on how many sockets I can have on the ring as I am looking to extend my existing ring into the new build.

5.
Can you run cat 5 and tv/phone cables with the mains cables when going through joist? and how often do I need to clip them in the joist voide?

Now for the new Kitchen bit...
1.
I need to run in a new cooker cable however I have an existing one in my old kitchen so can I just joint that one....(I bet I cant!!!)..

2.
Can I extend the existing earth and ring main to the new kitchen?
3.
How close can I have a socket to the sink?
4.
Can I just run a 13a spur of the kitchen ring main to feed the under cubboard lighting?
THE END...
Sorry for the long post .

Thanks in advance .

 

[Spark1964]

Ok here we go -

1.
can I just extend the existing ring main in the existing 3 bedrooms into the new 2 bedrooms? and if so what depth and what size hole do I need to make in the new joyce which I need to drill through?

Yes you can but you will need to ensure that any alterations to the circuit are protected by a 30mA RCD to comply with BS 7671 (17th Edition Wiring Regs). You will also need to consider the additional load although bedrooms are normally minimal additional load. Holes = as small as possible (not a structural engineer but 25mm will be fine) and 50mm from the finished surface of the joist.

2.
Do I need some metal covering over the cable and behind the plaster board when I come up the wall in the new bedrooms?

No but note the wiring zones (see point 4), also if less than 50mm deep then circuit needs to be RCD protected.

3.
Can I just extend the lighting circuit from the other bedrooms into the new bedrooms?

Yes

4.
Are you aloud to run 2.5 cables for a ring main horizonlaly around a room plus is there a limit on how many sockets I can have on the ring as I am looking to extend my existing ring into the new build.

Wiring zones - basic rule is vertical or horizontal if the run is in line with an accessory - ie if you have a socket in the centre of your wall you can wire up ,down, left or right in straight lines! - Also within 150 mm of wall reveals or ceilings. No limit to number of sockets but do consider load.

5.
Can you run cat 5 and tv/phone cables with the mains cables when going through joist? and how often do I need to clip them in the joist voide?

Advisable to keep 150mm apart and clip every 12" max as a rule

Now for the new Kitchen bit...
1.
I need to run in a new cooker cable however I have an existing one in my old kitchen so can I just joint that one....(I bet I cant!!!)..

Bet you can !, but again the same rules apply as per RCD protection, depth and wiring zones.

2.
Can I extend the existing earth and ring main to the new kitchen?

If you mean extend the main equipotential earth bonding (possibly your water stop tap??) then yes you can, but this really should be soundly mechanically crimped. Ring can be extended but, unlike bedrooms, be very wary of your additional load if this is a new 'modern' Kitchen. If you can, then it is advisable to wire the Kitchen on it's own new ring main.

3.
How close can I have a socket to the sink?

No regulation on distance but common sense should prevail and it MUST be RCD protected.

4.
Can I just run a 13a spur of the kitchen ring main to feed the under cubboard lighting?

Yes providing the cable that you use is protected by the fuse in the fused connection unit - i.e 1.0mm cable / 3 Amp fuse etc.

In all of the above cases, please remember that if you are not a 'competent person' / trained electrician and qualified as a domestic installer as a minimum then you will need to either -

a) Employ someone who is, or
b) Advise your local Building Control Dept of your intentions (= £££)

Hope this helps.
Regards

 

[sparkwright]

You have asked a lot of questions, and the questions you have asked prompt me to suggest you get a qualified electrician to carry out the work.

1) You may be able to extend the existing bedroom ring, but a new ring may be easier and may save disruption and unnecessary joints. The hole in the joist will depend on the thickness, but a row of 25 mm holes should cover all the mains wiring for the extension. Seek advice before drilling holes to avoid weakening the joists.

2) You don't need any protection on the cables if in safe cable zones. Even pvc capping would be more than enough.

3) You may be able to extend the lighting circuit if there is no risk of overloading it and it's in good nick and has complete earth wires in it. If you can it may be more desirable to install a new circuit.

4) The floor area of a ring must not exceed 100 sq m. Number of sockets unlimited. Again, more desirable to install new circuit. You can run cables horizontally, but more desirable to run vertically, be it upwards or downwards. Hard to fit extra sockets later when there are cables buried in the wall in the way.

5) You should keep these cables well away from mains cables wherever possible. Not sure about clip spacings, look it up yourself.

1) You could extend the cable if the junction box is accessible. Crimped or soldered joints don't have to be accessible, despite the fact they could easily be done wrong.

2) By earth, you mean bonding cable? You can extend with correct butt crimp and crimping tool. Replace fully if practical. It may be possible to extend kitchen ring, more detail required really.

3) How close do you want it?

4) A 13 amp fused spur from the sockets to feed cupboard lighting is acceptable, you would usually fit a 3 or 5 amp fuse.

The question here is how competent are you to do this work? There are many factors here I don't think you have considered and I strongly recommend a qualified electrician carries out the work. This is a very big job. If your house was built in 1985 you may not have much in the way of RCD protection. You need an electrician.

 

[echoes]

I've just spent ages typing a reply to a new thread and since starting, 2 others have already replied, but here it is anyway.....

Juyst because someone will ask sooner or later - on your building plans submission you will already have indicated how you will comply with Part P, so do that.

You ask some questions that are basically about electrical design, and without knowing about your existing circuits, your house's layout and size, they are impossible to give accurate answers to. So I haven't answered them.

I have tried to give you some answers - they are incomplete with respect of design so please read up further before doing the work. Search the forum for ban-all-sheds, and sooner or later you will find a good reading list among the bickering.

However....

1.
can I just extend the existing ring main in the existing 3 bedrooms into the new 2 bedrooms? and if so what depth and what size hole do I need to make in the new joyce which I need to drill through?

http://electrical.theiet.org/wiring-matters/14/build-regs-not-part-p.cfm?type=pdf

Centre of joist. Max 0.25 of joist thickness (you won't need anything like that size).

2.
Do I need some metal covering over the cable and behind the plaster board when I come up the wall in the new bedrooms?

No. But keep all cables in safe zones, which are defined horizonally and vertically from the socket.

3.
Can I just extend the lighting circuit from the other bedrooms into the new bedrooms?

Yes, provided the length of the extended cable is such that Zs and voltage drop are within acceptable limits, and the load is still below the circuit's design current.

4.
Are you aloud to run 2.5 cables for a ring main horizonlaly around a room plus is there a limit on how many sockets I can have on the ring as I am looking to extend my existing ring into the new build.

Yes, but better to run the vertically up from under the floor. Esp as you hav dot & dab. No limit to number of sockets. Again, ring length may be limited by Zs and voltage drop, but unlikely for a domestic ring final. Check that 2.5 mm cable is suitable (insulation etc).

5.
Can you run cat 5 and tv/phone cables with the mains cables when going through joist? and how often do I need to clip them in the joist voide?

Keep them separated from mains cables by at least 50mm i.e. different holes. I wouldn't bother clipping them - only where necessary to keep them away from pipes and cables.

Now for the new Kitchen bit...
1.
I need to run in a new cooker cable however I have an existing one in my old kitchen so can I just joint that one....(I bet I cant!!!)..

Kitchen work is notifiable, so you need to display competence to building control before starting, or get an electrician.

Depends on load, cable size, MCB size etc etc etc. Electrian best to advise here or specifics needed.

2.
Can I extend the existing earth and ring main to the new kitchen?

Earth???

A better design may be to have the kitchen supplied by its own ring or radial circuits. Much more research required, or get an electrician to design & install your kitchen circuits.

3.
How close can I have a socket to the sink?

As close as will not be splashed. 300mm min is often quoted.

4.
Can I just run a 13a spur of the kitchen ring main to feed the under cubboard lighting?

3A spur should do. There are other ways though.

 

[ban-all-sheds]

'

Juyst because someone will ask sooner or later - on your building plans submission you will already have indicated how you will comply with Part P, so do that.

Which is what I was going to do as soon as I started reading the original post, and I'm going to now having only skimmed it, and the replies, once I got to the end of the 2nd sentence.

Washerman - what did you tell the council on your application for Building Regulations approval would be the way you would ensure the electrical work would comply with P1?

If by tacit acceptance of what they said they would assume, or by copying their words without thinking about it, you said you'd be using an electrician then if you don't do that you are going to be up S.C. without a paddle when it comes to getting your completion certificate from them. And in that you'd be the latest in a line of people who've come here with tales of woe about DIYing electrical work as part of a larger project and then finding that the council will not give them a completion certificate.

The questions you are asking show that you do not have anywhere near enough knowledge to be tackling the electrical work for your extension.

Please get an electrician asap, or it will all end in tears.

 

[washerman]

Thanks all looks like a spark will be doing the work.
Washerman.