I can’t see where the 2 cables going to the ring socket start or finish so do it matter which one is used to extend. thanks.
1 new double socket on ring
- Thread starter lmhud
- Start date
I can’t see where the 2 cables going to the ring socket start or finish so do it matter which one is used to extend. thanks.
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Provided the existing socket is on a ring final circuit then the new socket can be connected as a spur from the existing socket.
https://www.flameport.com/electric/socket_outlet_circuits/ring_spurs_socket.cs4
https://www.flameport.com/electric/socket_outlet_circuits/ring_spurs_socket.cs4
I need 2 doubles. 1 either side of bed. The above diagrams are for 1 extended ring double. I will be taking a spur from original ring double to other side of bed.
You can only have 1 spur. So I need this extended socket.
Appreciate the reply.
You can only have 1 spur. So I need this extended socket.
Appreciate the reply.
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Either is permitted total cable length should not exceed 106 meters, since we can't measure length we measure the loop impedance, the line - earth loop impedance should not exceed 1.36 Ω with a B type MCB this is as type B magnetic trip is up to 5 times the thermal rating so 160 amp, so 230/160 = 1.44 add a safety margin so times 95% = 1.36 Ω to ensure the circuit will trip within the time allowed with a short circuit to earth, also looking at volt drop this will allow 0.59 Ω above the incoming supply impedance so if that is 0.35 Ω then 0.94 Ω line to neutral or more often measured as short circuit amps so at least 245 amps.
And of course the minor works certificate should be filled in.
Since the meters to measure are expensive, I would suggest once completed when you can you get an EICR done to highlight any errors. Although not sure all the testing is really required with a RCD protected circuit as even if the 1.36 Ω is exceeded the RCD will still work within 40 mS and in the main equipment today is not that sensitive to volt drop. However clearly the RCD does need testing with a proper tester. And one has to be careful to ensure the ring final is actually a ring with line, neutral and earth to ensure no over load can exist for any appreciable time.
And of course the minor works certificate should be filled in.
Since the meters to measure are expensive, I would suggest once completed when you can you get an EICR done to highlight any errors. Although not sure all the testing is really required with a RCD protected circuit as even if the 1.36 Ω is exceeded the RCD will still work within 40 mS and in the main equipment today is not that sensitive to volt drop. However clearly the RCD does need testing with a proper tester. And one has to be careful to ensure the ring final is actually a ring with line, neutral and earth to ensure no over load can exist for any appreciable time.
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There is nothing in the regulations to stop you having two spurs, as long as the terminals have sufficient room. And in a bedroom you will not be loading them much anyway.
I’m confused by that as it says this
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Well, that is one person's interpretation of the regulations. It is not what is actually stated.
I wouldn’t be able to get 4 cables into 1 socket. It’s hard enough trying to get 3.
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It's your call. I was just trying to help you avoid those nasty junction boxes!
Appreciated.
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I would say the appendix supports @flameport as to if the appendix of BS 7671 is considered as BS 7671 can't answer, but students taking the exam are testing on questions from the appendix.
I would say no more than 3 wires in any terminal, this ensures all wires are gripped well, once 3 is exceeded only can end up not being gripped, one must ensure any cable is not over loaded, and 2.5 mm² is not rated at 32 amp, so one needs to do some thing to ensure the rating is not exceeded, however as long as there are no branches on a cable, it is permitted to put the protective device at the destination rather than origin if some rules are obeyed.
However putting two sockets on a spur means there is a branch on the cable, the first socket is the branch, so the overload must be at the origin, so being pedantic yes the diagram shown from @flameport is not quite correct, as it does not show the size of the overload, and with a 25 amp overload you could do as shown, and one cure when we find as electricians that there are unfused spurs from unfused spurs is to swap the 32 amp overload device to a 25 amp overload device.
However we know @flameport is talking about a standard ring final from a 30 or 32 amp protective device so is correct. I like the LAP grid system, where you can put a fuse, switch, and 13 amp socket in a standard double socket face plate, (4 module) and that is what I used to extend a spur, as shown here
.
I would say no more than 3 wires in any terminal, this ensures all wires are gripped well, once 3 is exceeded only can end up not being gripped, one must ensure any cable is not over loaded, and 2.5 mm² is not rated at 32 amp, so one needs to do some thing to ensure the rating is not exceeded, however as long as there are no branches on a cable, it is permitted to put the protective device at the destination rather than origin if some rules are obeyed.
However putting two sockets on a spur means there is a branch on the cable, the first socket is the branch, so the overload must be at the origin, so being pedantic yes the diagram shown from @flameport is not quite correct, as it does not show the size of the overload, and with a 25 amp overload you could do as shown, and one cure when we find as electricians that there are unfused spurs from unfused spurs is to swap the 32 amp overload device to a 25 amp overload device.
However we know @flameport is talking about a standard ring final from a 30 or 32 amp protective device so is correct. I like the LAP grid system, where you can put a fuse, switch, and 13 amp socket in a standard double socket face plate, (4 module) and that is what I used to extend a spur, as shown here
.
I wonder what sort of cables you have.
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