The spur must be connected to the existing circuit using the same cable as used in the main circuit. You can see how to wire a spur to an existing socket from the images below. The first image is how the back of your double socket should look and the second is the wiring for a spur.
A general rule for a ring main is that if you only have two cables in the back of an existing socket then it is ok to spur. However, if you have a radial circuit with two cables coming in and out, this may be the last socket on that circuit and already has a spur.
Please check with a qualified electrician if you are not sure and read our section on electrical safety and Part P Building Regulations linked above. A spur can be added to any part of the circuit providing the rules above are followed. If there is not an existing socket near enough, you can connect into the cable by means of a junction box for your new spur.
The wiring for a junction box can be seen here. Junction boxes come rated for different uses by the amps they are allowed to carry. A 30amp junction box should be used on a ring or radial circuit feeding sockets only. The junction box must be fixed solidly to a suitable surface and must not just "float around suspended by the cables it joins. The cables to and from any spurs you connect must be protected by a conduit of some kind; be it on the surface or buried in the wall.
If you bury cables in the wall they must only run vertically, not horizontally. Cables may be placed in floor or ceiling voids but not amidst, or wrapped in, insulation where they may become too hot. I really don't get why everyone seems to struggle with this fundamental concept. Can I ask what in particular makes you think you can put a junction box and add a radial spur on the ring and just add as many sockets as you like?
It used to be the rule no more spurs than points on the ring. So a ring with 10 points could have one spur each point. I'm referring to unfused spurs of course. A good practice thing really. Oh, I see. Actually strictly what we meant was " is accepted as a standard circuit requiriung no further detailed analysis" not simply " not permitted.
I recall the "one spur to one ring device" being inferred in a diagram in one of John Whitfield's guides circa odd. That included spurs from junctions boxes into the ring, not just spurs from actual accessories. Not sure if any other guide or earlier regs mentioned it? IronFreely Posts: Joined: 06 November I've always thought that un fused Spurs are a bit of a risk anyway, if you consider that most ring final circuits are going to be run in 2.
I nearly always fuse my Spurs, I would advise the OP to do the same. Not as such IronFreely. The likelihood of such an overload is very small, is likely to be short a kettle and a heater for example and will not do anything nasty.
See my other post on cable ratings and temperatures. The number of spurs is not limited in the current regs, and you can always add a junction box to get more points anyway, and this reg may have been an attempt to limit the use of JBs! Just a question, have you ever seen a melted ring cable? I thought not! I had always assumed that the reg was intended to stop you stuffing too many conductors into an accessory terminal.
Two 2. A single cable is added from the new socket, and connects to an existing socket on the ring. A spur can alternatively be connected at the consumer unit, which although might seem incorrect, is actually no different to connecting to an existing socket outlet. The spur socket only has a single cable, with the connections to Live, Neutral and Earth.
This is exactly the same as connecting at the end of a radial circuit. The other end of the cable connects to a socket on the ring, so there will be three cables in that socket. Connect the other end of the spur cable to the new ceiling rose in the same way. To connect the light fitting to the rose, follow the instructions for installing ceiling lights or installing a wall light. To me that means the max sockets you can have for a 32a ring would be only be 4 sockets!!!!!
It is fatter, heavier, more stiff and more expensive. There just doesn't seem to be any need to use it for domestic lighting. If it is a final ring circuit with a 32A mcb or 30A fuse you can take 1 spur from each socket. If it is a 20A radial cct you can do what you like. One rule of thumb is to assign a maximum draw of 1.
The IET Wiring Regulations BS permit an unlimited number of 13A socket outlets at any point unfused single or double, or any number fused to be installed on a ring circuit , provided that the floor area served does not exceed m 2. Break the circuit at the socket in question. Check for continuity between the two line conductors. If continuity is present, it's likely to be on the ring could be on a figure of 8 loop. To confirm, remove the line conductors at the board.
Under the new , revised regulations, electrical work undertaken in kitchens such as adding a new socket or work outdoors such as installing a new security light will no longer be notifiable unless a new circuit is required.
This will mean less work has to be notified by electricians. Re: Adding wall lights - run from an existing socket?
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