Adding sockets to an existing radial circuit

Del007

I want to add 2 double sockets to an existing radial circuit. There are currently 4 double sockets and 2 single sockets on the circuit. It is protected by a 20A mcb and is RCB protected.

What's the best practice in order to do this?

I would like to take a feed from one of the single sockets and loop it on to the 2 new sockets. Am I being compliant with the rules and regulations?

Thanks for your help.

Luckysasha

From what I can remember from my days in FAS, you can only have 10 sockets on a radial circuit. So you may need to install a new radial or add your 2 new sockets to the existing radial and go from the last socket back to the board turning the circuit in to a ring. Only trouble is you will need an electrician to do this work. Not a diy project

Del007

I am an electrician I haven't worked at it in quite a number of years though. I'm out of touch with the rules though which is why I'm seeking the advice of the experts in here.

Isn't a double still counted as 1 socket though? So I've only 6 sockets on the one circuit

seaniefr

Del007 wrote: »

I am an electrician I haven't worked at it in quite a number of years though. I'm out of touch with the rules though which is why I'm seeking the advice of the experts in here.

Isn't a double still counted as 1 socket though? So I've only 6 sockets on the one circuit

it's really down to the length of the run from the fuse board to the furthest socket in the circuit. If you are over a certain resistance value then the MCB (assuming a B type here) will simply not function in time to prevent an overcurrent situation. As regards the 10 points that may be fine in a certain situation but if someone is plugging in heaters or some other heavy loads that's a different situation entirely.

seaniefr

I also forgot to mention as per 2nd poster that if it's a domestic situation then it is classified as restricted works by the CER which means you need to be a RECI member to carry out the work if it involves additions or alterations to the board.

Del007

seaniefr wrote: »

I also forgot to mention as per 2nd poster that if it's a domestic situation then it is classified as restricted works by the CER which means you need to be a RECI member to carry out the work if it involves additions or alterations to the board.

So to add to an existing circuit then the electrician needs to be a RECI member? I won't be going near the board, just adding to an existing

2011

Links are provided in the forum charter that explain the situation.

bassey

7 posts in and the OP hasn't received a clear answer.

Yes, provided you're a competent person and don't work on the distribution board, you can loop from one of the single sockets to your new double sockets, you're correct the the regs state that there can be 10 points on a radial circuit and double sockets only count as 1 point.

When you've extended the radial by two points there will be 8 points in the circuit, which as you say is protected by a 20A RCB, complying the regs.

I don't see any reason why you would need to work on the distribution board to do this task, so it counts as minor works.

seaniefr is right above though that if the length of the run is quite long you may need to use a different protection device or even larger cable than 2.5 mm sq.

Hope that helps answer your question.

P.s the constant restricted works talk on this forum is insufferable lately.

GreenFolder2

You've also got to calculate the likely load.
You can have a lot of sockets all of which are plugged into very small load electronics.

Or, you can have a house where you could have several heaters plugged into a radial and that's where you'll get tripping of the MCB.

In my house each room is basically on its own radial with 4 double sockets. The hallways share some of the radials and the kitchen has 3 and the utility 2 and there's one for the garage, the boiler house and so on.

Just be very careful you've planning the loads correctly. Adding extra sockets to kitchen radials for example isn't always appropriate as the appliances used there are largely high power consumers. You might be better off having an electrician add a new circuit.

Ten sockets per radial is only a maximum arbitrary limit. Like the speed limit on a country road - common sense still applies.

Del007

Thank you all for your replies.

There's a single socket inside in the wardrobe that I will be extending from. It's not really accessible and the other single socket in the wardrobe is half covered by the back of the wardrobe and it's impossible to plug something into it.

Am I going over board if I feed to a fused spur from the single socket and then onto the 2 double sockets.

The run is about 2 metres extra at most

DublinDilbert

Del007 wrote: »

Am I going over board if I feed to a fused spur from the single socket and then onto the 2 double sockets.

The run is about 2 metres extra at most

Yes a fused spur is a bad idea here and definitely not the norm. I wouldn't like to have a fused spur tucked away in the back or a wardrobe. It could cause more hassle than anything.

GreenFolder2

DublinDilbert wrote: »

Yes a fused spur is a bad idea here and definitely not the norm. I wouldn't like to have a fused spur tucked away in the back or a wardrobe. It could cause more hassle than anything.

Fused spurs aren't needed on radial circuits, only on rings.

You need to be very careful that this is definitely a radial and your not connecting to a ring.

Rings are an odd UK configuration not used in many places. Your feeding the power to every socket from both sides as both ends of the ring are connected to the breaker. This, in theory, allows you to rate the fuse protection higher than would be acceptable on a radial as the load is being fed by two sets of conductors - each side of the ring.

If you then take a spur off the ring, it's only feed from one side, so it's a normal radial circuit. So to protect the wiring from overheating, you have to use a fused spur. Otherwise you've a 32A radial with inappropriately thin cable.

I really dislike the concept behind rings. They assume that everything is evenly spaced along them and they can fail dangerously if the ring is accidentally split by poor workmanship or botched DIY. Someone installs a socket and the connection is loose on one side. The ring splits and next thing you've two radials fed from one 32A breaker. There'll be no fault symptoms but, plug in a few heavy loads and you've a potential house fire as the wiring will get hot.

Also where they're used in the UK you can get a load of appliances in the kitchen clustered together. If the ring is long and they're close to one side of it, you'll get rather warm wiring too.

On top of that it's forcing the use of fused plugs. Again due to poor design, I find the plugs are prone to overheating as the fuse holders in many of them are just a brass clip attached to a loose live terminal. If the fuse isn't carefully seated, or the holder is bent out of shape you get very hot plugs and melted sockets.

Or, because the UK pin configuration is close to continental unfused 2-pin plugs, enough to allow a europlug to actually work in a UK / Ireland socket, you find small appliances plugged in directly into 32A circuits without any local fusing. They work and end users don't understand there's any risk involved.

In my opinion rings generally an awful, over complicated concept in domestic settings and they're not used elsewhere at all. Unheard-of in any other system - North American, other EU countries, Australia/NZ, etc etc