Ring main extension

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Hello again everyone.

I have a double socket in a bedroom. I added another socket to the room by running 2 x 2.5mm cables from the original socket. The intention was to extend the ring main wiring to incorporate the new socket. Next to the new socket I have also put a FCU that will supply a 13A socket in my loft. The output of the FCU is a single 2.5mm cable. The FCU is connected so that it is part of the ring main too.

Does this need to be inspected? for part P. I ask becasue originally I was going to do a single spur and understood that it did not need inspecting, but now I have extended the ring main.

I think it still counts as extending a circuit that is already there, but just want to check.

Thanks in advance.
 
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If it is in a bedroom it is not notifiable, however it sounds to me as if you have extended it wrongly.

The ring must be a ring (unless you are making a single-outlet spur).

Taking two cables to the same point is not a ring.
 
Thanks for the advice John.

I was trying to say that 2 cables leave the existing socket. One goes to new socket. one goes to FCU. another cable joins these together, so it is a ring.


However, I have not connected the 2 new cables to the existing socket yet. I was hoping to use a 30A connector block to join one new cable to one old cable, then connect the other 2 in the plug socket connections. However there is not enough room in the 25mm metal box to fit a connector block. Would it be ilegal to connect all 4 cables together, so in effect I will not add a ring, but add a spur that consists of 2 wires going to new socket & FCU. ??
 
Yarn said:
I was trying to say that 2 cables leave the existing socket. One goes to new socket. one goes to FCU. another cable joins these together, so it is a ring.

No, that's not right. It is an extension on the ring. The shape of the extension is not relevant.

Yarn said:
However, I have not connected the 2 new cables to the existing socket yet. I was hoping to use a 30A connector block to join one new cable to one old cable, then connect the other 2 in the plug socket connections. However there is not enough room in the 25mm metal box to fit a connector block. Would it be ilegal to connect all 4 cables together, so in effect I will not add a ring, but add a spur that consists of 2 wires going to new socket & FCU. ??

there is a way of enlarging the ring which might suit you. You have to take one leg of the ring (say, the cable that enters the LHS of the socket box) and lead it it away to the new sockets, then bring it back and connect it to the other leg (say, the cable that enters the RHS of the socket box). The two legs must not be connected in the socket box.

One way of doing this is with a Dual Box, which is a little wider than a double socket, but holds two single-gang accessories.
 
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Thanks John,

I think we were both talking about the same thing. I meant to say in my last post that I would wire the existing socket so that it was still a part of the ring main.

Thanks for the advice about the double socket. ill try and find one. I see how using 2 single sockets would allow 2 independant connections at the socket box and thus keep the ring.

Cheers.
 
All you need to do is break the new ring. You need a single feed to the FCU and this can then feed both the new SO and your loft. Remove the link between the current and new sockets. This will derate the feed to 13A.
 
But Crafty, In your 'X' diagram the larger box could be the 2 single sockets mentioned by John D, then the diagram would be correct!
(seen as the 2 red in/out's are not connected).

If all the connections go to a single node on the large box then this incorrect. - which in reality, would be the only possible way if I use a standard double socket.

The other diagram with e very small box, which i assume is a connector block was how I was originally proposing to do the job, but the connector does not fit inthe socket box. Hope santa brings me a patress spacer or some magic elves to sort this out.
 
homebase sell a double socket that is made from two singles (not a duelbox tho) that fits a standard double socket box, it comes with a jumper linking the two but you can remove this. they are expensive tho (about £15 and fancy looking so wont match other sockets)
 
Yarn,

You can feed the loft and the new socket from the fused SO. This creates a radial from the original socket, derated to 13A (but assuming you are not building a workshop in the attic) this will be plenty of power.
If you disconnect the cable linking the old and new sockets you don't need to do any more work.
 
Creating rings from rings is poor design. I know the method described is effectively spliiting one SO to break the ring but just picture the layout. You end up with an unbalanced ring and increase the chances of adding interconnections.

Adding a fused spur radial makes what you are doing easier to test (assuming you are testing) and makes it less likely that a fault in your loft will take out your current ring. Also 13A gives you around KW so you are unlikely to overlaod this in normal use.
 
13A is more like 3kW. when we visit the parents we stay in the loft (its semihabitable -only ladder access but good fire escape onto flat roof etc) we put on the electric heater, then the wife starts dying her hair with her 2k hair dryer...etc it soon adds up! channeling is the hard bit cable is cheap -i know what i would do!
 
I meant 3KW and I stand by my advice. It is not good practice to loop a ring from a ring. If you're making the loft habitable, intend to live in it and are worried about the load on the FCU, then channel back to the DB and stick the loft on it's own circuit.
 

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