adding sockets to a radial circuit

[Joneedshelpwithwiring]

There are 3 radial circuits in my house which run from downstairs to upstairs with a double socket in each room. I want to add further 6 double sockets downstairs. Can I just extend the radial circuit indefinitely?

 

[ban-all-sheds]

There is no limit to the number of sockets you may have on a radial circuit - there are limits on the floor area that they may serve:

2.5mm cable with 20A protection - 50 sq m

4.0mm cable with 30/32A protection - 75 sq m

But if you want more sockets downstairs why not add them to the downstairs ring?

Now, forgive me if I'm suspicious, but 3 separate circuits each feeding a single socket is a very strange idea - are these really radials? Or are they spurs off the ring?

 

[Joneedshelpwithwiring]

There is no main ring circuit. I am trying to help my little sis who has recently bought a 1920's 2 up 2 down. The wiring is clearly more modern than that - don't worry. It is a weird fuse box - very clearly labelled. All of the fuses are 15amp, except the cooker fuse which is 30amp. The radial circuits run from the top floor to the ground floor with only 1 double socket on each floor in each room. Apparently the previous owners had extension cables all over the place. We were hoping to run a spur off each existing double socket, with two singles running off one double. My sister has knocked the front room through to the dining room downstairs so the total sq metrage is now about 30 m sq. Does that still sound dodgy? We are both completely new to this kind of thing, although it seems quite logical.

 

[ban-all-sheds]

Sounds OK - a bit unusual, but from what you've described it's both safe and legal, provided it's cabled with 2.5mm. You might like to consider having it rewired in a more conventional form and having a few more sockets (and possibly a shower circuit installed?). I know that funds are probably tight given that she only bought the house recently, but it'll only get more expensive after Part P. If you can find an electrician on a word-of-mouth recommendation who's happy to charge less if you do some of the grunt work then it shouldn't be fabulously expensive for such a small property - if you post your approx location here you might find that one of the professionals on the forum can give you a rough idea of cost.

I would suggest though that whatever you do you have it inspected. Whoever installed the wiring may have had a perfectly sound reason for doing it like that, or they may have been an idiot - it wouldn't hurt to find out if there are any hidden horrors. Again, small property, small circuits, shouldn't be too expensive.

 

[Joneedshelpwithwiring]

She's in Tooting, South West London

 

[Joneedshelpwithwiring]

Thanks ban-all-sheds. What's Part P?

We were planning on adding a spur to each existing socket on the radial circuits with a double socket on each, but one with 2 single sockets. Would I effectively add a spur to a spur for the single sockets or have all of the cables going into the original double socket?

I don't think that my sis can afford to have the place re wired and given that they had to rip out the (non electric) shower because it was leaking from behind the tiles, I think that's her last concern at the moment. I know it would make sense, but right now she is focusing on getting the right number of sockets into the sitting room downstairs before the plaster arrives to finish off his job so he can fill in all the holes we make!

 

[ban-all-sheds]

Thanks ban-all-sheds. What's Part P?

How long have you got?
See the discussion document and consultation results.

And there's more stuff on that website - go to http://www.odpm.gov.uk and search for Part P.

Also, search this forum, and the Screwfix one for terms like Part P, regulations, qualifications etc etc, and see the uk.d-i-y newsgroup.

We were planning on adding a spur to each existing socket on the radial circuits with a double socket on each, but one with 2 single sockets. Would I effectively add a spur to a spur for the single sockets or have all of the cables going into the original double socket?

You can't have two spurs coming off one socket. You can have a single spur feeding two single sockets, one after the other. But in //www.diynot.com/forums/viewtopic.php?t=5429 it looks as though where you want to do this is at the end of the radial anyway....

I don't think that my sis can afford to have the place re wired and given that they had to rip out the (non electric) shower because it was leaking from behind the tiles, I think that's her last concern at the moment. I know it would make sense, but right now she is focusing on getting the right number of sockets into the sitting room downstairs before the plaster arrives to finish off his job so he can fill in all the holes we make!

I would really advise at least an inspection - it sounds like an odd installation, and whilst there's nothing wrong, per se, with an odd topography there might be a great deal wrong with odd cable choices or physical installation methods....

 

[paulh53]

All of the fuses are 15amp, except the cooker fuse which is 30amp.

Do You Not Have Any 5 amp Fuses For The Lighting

 

[Joneedshelpwithwiring]

Thanks you again ban-all-sheds! I will definitely suggest an inspection to my sis. Think I've got the gist with the whole adding sockets to a radial circuit now... I asked two questions in two different places because as I learnt more and looked up more stuff I realised that I had asked the wrong question initially! Think I'm there now. Am planning on getting someone to look at the layout etc before we do anything and subject to it being OK I am going to just extend each radial circuit so that each circuit has 4 double sockets running off it in total. Have 2.5mm cable and apt sockets. Will disconnect power before touching anything, so will avoid any interesting hairdos!

To Paulh53 - yes, sorry the lighting is on 5A fuses but thatnkfully we don't need to do anything to that!

 

[snowflake]

There is no limit to the number of sockets you may have on a radial circuit - there are limits on the floor area that they may serve:

2.5mm cable with 20A protection - 50 sq m

4.0mm cable with 30/32A protection - 75 sq m

But if you want more sockets downstairs why not add them to the downstairs ring?

Now, forgive me if I'm suspicious, but 3 separate circuits each feeding a single socket is a very strange idea - are these really radials? Or are they spurs off the ring?

Does'nt the actual length of the cable and the choice of MCB or Fuse restrict the number of sockets in a radial circuit. I'm really interested in this as we want to increase the number of sockets in the kitchen which is wired up in 4mm cable. Access would make changing to a ring main very difficult. Response would be very much appreciated

 

[dingbat]

Does'nt the actual length of the cable and the choice of MCB or Fuse restrict the number of sockets in a radial circuit.

No. The MCB/Fuse is there to protect the cable from overload, so it doesn't matter how much you plug in, eventually the circuit protective device will do its job and trip/blow. B-A-S is correct with his previous statements and you can add as many sockets as you like to your 4 sq mm radial as long as your kitchen isn't bigger than 75 sq m and you don't use higher than a 32A MCB or 30A fuse. And, of course, you extend with 4 sq mm cable.

(And naturally you will carry out the obligatory electrical tests in accordance with the regulations before you re-energise the circuit !)

 

[ban-all-sheds]

Does'nt the actual length of the cable and the choice of MCB or Fuse restrict the number of sockets in a radial circuit.

It's the other way round - the choice of MCB or fuse restricts the length of the cable.

You should get a copy of the On Site Guide.

 

[plugwash]

in the uk we don't restrict sockets per cuircuit

some countrys (france for example) do but this just encourages more use of extention leads

 

[snowflake]

Does'nt the actual length of the cable and the choice of MCB or Fuse restrict the number of sockets in a radial circuit.

It's the other way round - the choice of MCB or fuse restricts the length of the cable.

You should get a copy of the On Site Guide.

Many thanks for the extremely speedy response. Where would a copy of the On Site Guide be available from ?

 

[ban-all-sheds]

Amazon or IEE to name but two.

If you buy from Amazon make sure that you're getting the latest (Brown cover) version.