Is spurring to make an additional socket something I can do myself? Reason Im asking is Im In the process of making a false chimney breast and having my TV inset in it, with sockets behind. Obviously cant get an electrician at the moment and no idea when, but I want to get on with building the framework. The nearest plug socket is approx 5-6ft away, one either side of TV. Also its a bungalow so can get under the floor for routing cables.
Spurring to make an additional socket
- Thread starter scottpetrie
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If the socket you want to connect to already has 2 cables, there is a good chance you can. (assuming house is currently to regulations)
That's assuming the 2nd cable isn't already a spur.
What you can't do is spur off a spur unless it's fed off an FCU.
Best check if it's a ring and if you're not sure then fuse it down just in case.
What you can't do is spur off a spur unless it's fed off an FCU.
Best check if it's a ring and if you're not sure then fuse it down just in case.
You don’t wanna add a fuse just incase if it’s only powering a tv
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Basic idea is cable is protected from overload either by what it feeds or by what it is fed from, since all plugs in UK are fused it is permitted to rely on that fuse, but that only works if feeding one device, i.e. single socket, double socket, or fused connection unit (FCU) and for any new also must be RCD protected.
Protection is also done on the supply side, but a 2.5 mm² cable is only considered as good for 20 amp, (it does change according to how fitted so that is the minimum valve permitted for a cable used for a ring final) so it needs feeding from both sides so in effect the cable is doubled up, and feed from a 30 amp fuse or 32 amp MCB/RCBO, this is the whole idea of the ring final. However we can also use heaver cable 4 mm² for example and feed as a radial, and still use the same protective devices, so just because it is fed with a 32 amp trip does not mean it is a ring final.
We can also of course use a 20 amp overload and 2.5 mm² cable as a radial, however with a ring to keep within the volt drop requirements we can use 106 meters of cable, but with radial at 20 amp only 32 meters, so for years the ring final has been the preferred method.
Because the ring final is considered the final circuit hence the name, we don't call a fused radial from it a radial which really it is, but a fused spur, not sure why but it is, and when relying on the fuse in the plug we call it a spur or unfused spur.
So job one should be work out what the socket is that we are taking the new socket from, if previous people have followed the rules, then if it has two cables, or supplied with a 25 amp or less overload, then if also RCD protected you can take a spur, however that is assuming no one has broken the rules before you, my dads house had unfused spurs off unfused spurs every where, and also fused spurs off fused spurs, clearly my dad did not know the rules, he told me he was very proud when he moved into the house in 1954 as it had 6 sockets, and my granddads house only had two. When finally re-wired found wooden back boxes as well, official as makers name on them. OK a lot was wired in the old 7/0.036 cable which is a little thicker than 2.5 mm² but some cable did show signs of over temperature damage.
In theory we should test the loop impedance as well as supply protective device size, and also tripping times for the RCD, so in theory sockets should not be added by DIY guys as they don't have the test equipment, in practice we know it is regularly done, and also errors made, in theory every 10 years (5 years with rental property) or change of occupant all wiring should be tested, but with owner occupied houses that rarely happens.
So take some time and read up on how ring mains work, then see what you have, and decide if you can extend, there is no point any one on here saying no you must not fit your own sockets, this is UK not Australia, we have not passed laws to stop DIY yet. But clearly care is required.
Protection is also done on the supply side, but a 2.5 mm² cable is only considered as good for 20 amp, (it does change according to how fitted so that is the minimum valve permitted for a cable used for a ring final) so it needs feeding from both sides so in effect the cable is doubled up, and feed from a 30 amp fuse or 32 amp MCB/RCBO, this is the whole idea of the ring final. However we can also use heaver cable 4 mm² for example and feed as a radial, and still use the same protective devices, so just because it is fed with a 32 amp trip does not mean it is a ring final.
We can also of course use a 20 amp overload and 2.5 mm² cable as a radial, however with a ring to keep within the volt drop requirements we can use 106 meters of cable, but with radial at 20 amp only 32 meters, so for years the ring final has been the preferred method.
Because the ring final is considered the final circuit hence the name, we don't call a fused radial from it a radial which really it is, but a fused spur, not sure why but it is, and when relying on the fuse in the plug we call it a spur or unfused spur.
So job one should be work out what the socket is that we are taking the new socket from, if previous people have followed the rules, then if it has two cables, or supplied with a 25 amp or less overload, then if also RCD protected you can take a spur, however that is assuming no one has broken the rules before you, my dads house had unfused spurs off unfused spurs every where, and also fused spurs off fused spurs, clearly my dad did not know the rules, he told me he was very proud when he moved into the house in 1954 as it had 6 sockets, and my granddads house only had two. When finally re-wired found wooden back boxes as well, official as makers name on them. OK a lot was wired in the old 7/0.036 cable which is a little thicker than 2.5 mm² but some cable did show signs of over temperature damage.
In theory we should test the loop impedance as well as supply protective device size, and also tripping times for the RCD, so in theory sockets should not be added by DIY guys as they don't have the test equipment, in practice we know it is regularly done, and also errors made, in theory every 10 years (5 years with rental property) or change of occupant all wiring should be tested, but with owner occupied houses that rarely happens.
So take some time and read up on how ring mains work, then see what you have, and decide if you can extend, there is no point any one on here saying no you must not fit your own sockets, this is UK not Australia, we have not passed laws to stop DIY yet. But clearly care is required.
If it's a spur and you have more than 2 double sockets on it then the feed needs to be fused - usually done with a fused connection unit, There isn't any specified location for the connection unit but 2.5mm has to be run to it. However as it might be nice to be able to switch it off as the ones on the socket might be hard to get at a switched fused connection unit that can be got at is a good idea.
Read up on safe zones - effectively this means that any socket or switch creates them horizonaly and vertically around where they are fitted. This rules out diagonal runs and can influence installing new items. Safe zones effectively means never drill holes there.
Used to be simple as only vertical was used - not really enforced though.
The actual rating, length and cables size used also depends on the supply resistance even the one provided for earth. It needs specialised equipment measure these. When people have earth provided by a lead sheathe on the incomer that can be a problem but usually overcome by having an rcd in the circuit as well. Modern CU's provide that. The more recent arrangement where earth is combined with neutral is likely to be fine but adds it's own complications to some other things that may have to be done.
Older 4mm radials rewires are likely to be stranded so easy to spot. Some people still use it as easier to lay but many suppliers just offer single cores as it's a bit cheaper. The over all size can give some idea which cable size has been used. Don't think I have ever seen any 7x0.036 but may have when pulling old rubber cable out long ago.
Read up on safe zones - effectively this means that any socket or switch creates them horizonaly and vertically around where they are fitted. This rules out diagonal runs and can influence installing new items. Safe zones effectively means never drill holes there.
Used to be simple as only vertical was used - not really enforced though.The actual rating, length and cables size used also depends on the supply resistance even the one provided for earth. It needs specialised equipment measure these. When people have earth provided by a lead sheathe on the incomer that can be a problem but usually overcome by having an rcd in the circuit as well. Modern CU's provide that. The more recent arrangement where earth is combined with neutral is likely to be fine but adds it's own complications to some other things that may have to be done.
Older 4mm radials rewires are likely to be stranded so easy to spot. Some people still use it as easier to lay but many suppliers just offer single cores as it's a bit cheaper. The over all size can give some idea which cable size has been used. Don't think I have ever seen any 7x0.036 but may have when pulling old rubber cable out long ago.
Okay. I could probably do this myself but wouldn't be confident testing to make sure its correct/safe. What about running an extension lead from the socket, under the floorboards, then back up through so its behind the new false chimney breast? Im in a bungalow so can get under my floors easy enough.
It's only a case of connecting live, neutral and earth connections up correctly, sleeving earth wire and tight enough in fittings. Best description of that is firmly but it's not that easy to over tighten.
From your description I would spur off to a switched fuse connection unit off one of the sockets then run cable to the sockets you want. That way you can fit as many as you like.
The socket you spur off creates it's own safe zone horizontally and vertically around it where cables can be run. These are shown as the same size as the fitting. You can tell which way they are run by unscrewing and lifting off the socket.
Best option after that depends on where they run. If down under the floor channelling in the same direction might damage cable. In that case I would break into the cable under the floor boards with a 3 way 30amp junction box. This sort of thing available from many. They are nice and simple and reliable.
https://cpc.farnell.com/pro-elec/k8...MIkvT7r8TE6AIVRbTtCh1kvAKREAQYASABEgJqFPD_BwE
Then spur off that to the SFCU. That sets it's own safe zones where it is fitted. Problems with safe zones crop up when cable is run around more than one corner. There must be a fitting on each face of a corner. The other safe zones are 150mm each side of an internal corner - it's used to run cables down or up to or for rings or radials etc and no need for a fitting to show they run there. Also the same distance below the ceiling - handy with flats or problems removing floorboards above etc.
Safe zones really mean don't knock nails in or drill holes here / if plaster etc need removing disconnect the circuit and proceed with care. Probably damaging cable if plaster is removed.
From your description I would spur off to a switched fuse connection unit off one of the sockets then run cable to the sockets you want. That way you can fit as many as you like.
The socket you spur off creates it's own safe zone horizontally and vertically around it where cables can be run. These are shown as the same size as the fitting. You can tell which way they are run by unscrewing and lifting off the socket.
Best option after that depends on where they run. If down under the floor channelling in the same direction might damage cable. In that case I would break into the cable under the floor boards with a 3 way 30amp junction box. This sort of thing available from many. They are nice and simple and reliable.
https://cpc.farnell.com/pro-elec/k8...MIkvT7r8TE6AIVRbTtCh1kvAKREAQYASABEgJqFPD_BwE
Then spur off that to the SFCU. That sets it's own safe zones where it is fitted. Problems with safe zones crop up when cable is run around more than one corner. There must be a fitting on each face of a corner. The other safe zones are 150mm each side of an internal corner - it's used to run cables down or up to or for rings or radials etc and no need for a fitting to show they run there. Also the same distance below the ceiling - handy with flats or problems removing floorboards above etc.
Safe zones really mean don't knock nails in or drill holes here / if plaster etc need removing disconnect the circuit and proceed with care. Probably damaging cable if plaster is removed.
Not permitted and never was. Junction boxes need to be accessible.
That depends one what is seen as accessible.
What about maintenance free JBs?
So basically spur from one of the existing sockets to a switched fused connection unit, then from there I can run cable to my new socket(s)?
They are permitted.
However any type of inaccessible connection should be avoided where possible.
That's where you could do with knowing if the socket you're spurring from is on the Ring or already a Spur as you wouldn't need to fuse down for a single spur off a ring.
If in doubt there's no harm in coming off the socket via an FCU even if it is just for a TV.
If your junction off the socket is being hidden then try one of these and get yourself some earth sleeving to go with your 2.5mm t&e.
https://www.tlc-direct.co.uk/Produc...PZWtm8wamVaV5QSRER3vlOEuWFdXNjJBoCVWcQAvD_BwE
Could I run the cable straight from the back of the socket to the FCU? Then from there to my new socket behind the TV?
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