Hi, Hope someone can help me. I would like to know if it is possible to install a fused spur in a ring main. Not as a spur from a double socket but actually included as part of the ring. Any help appreciated.
Can a fused spur be fitted into ring main
- Thread starter shaggy81
- Start date
Sponsored Links
Found it Appendix 15. Many thanks.
- Joined
- 27 Jan 2008
- Messages
- 23,663
- Reaction score
- 2,666
- Location
- Llanfair Caereinion, Nr Welshpool
- Country
No as if fused it's not a spur but a radial. But yes you can use a FCU to tap into a ring.
Sponsored Links
How is it not a spur - it's comming off a 'final circuit'!
If it came off it's own MCB in the CU it would be a radial final circuit.
If it's coming off a RFC, it's a spur, no matter how or where you join it.
- Joined
- 27 Jan 2008
- Messages
- 23,663
- Reaction score
- 2,666
- Location
- Llanfair Caereinion, Nr Welshpool
- Country
Seems I got it wrong. Re-read the red book and it seems there is no difference between spur and radial both can be new circuits.
Maybe you can explain "final circuit" my English would have thought it would have been the last circuit. However although radial is not defined circuit is and there is no way the assembly after a FCU can be considered as anything but a circuit in it's own right. So it seems we can have a final final circuit. Guess that would be at the VERY end!
Why, because it has it's own overcurrent protective device because of a change of current carrying capacity.
So, on your 'Schedule of test results', you have listed, (along with the other 'final' circuits'), every fused spur......because they are circuits in their own right........with their very own R1+R2, IR, Zs etc.
'Final Circuits' are as the name implies - the final circuits out of the DB/CU.
'Distribution Circuits' feed other CU/DBs.
'Spurs' are parts of a 'Final Circuit' that aren't part of the normal make-up of that circuit, and are sometimes fused.
It really isn't rocket science, and you don't need the regs to tell you this..
Ring Final Circuit - a 'final' circuit
Radial Final Circuit - a 'final' circuit
1.5mm, 2.5mm radial joined to RFC - a 'spur'
1.5mm joined to a 2.5mm 'Radial final circuit' - a spur
1.5mm, 2.5mm joined to a 4.0mm 'Radial final circuit' - a spur
2.5mm & additional socket connected between two sockets on 'RFC' - extension of final circuit
2.5mm joined to a 2.5mm 'Radial final circuit' - extension of 'final circuit'
4.0mm joined to a 4.0mm 'Radial final circuit' - extension of 'final circuit'
So, fused or not, if it's coming off a RFC, and not part of the 'ring', it's a spur!
Syntax error ?
No need to lecture Eric, simple discription error. The way I see it, you have a spur on a final circuit (radial or ring) and a spur off a final circuit.
On being part of the circuit and off being beyond a socket which is off the circuit.
Simples.......
No need to lecture Eric, simple discription error. The way I see it, you have a spur on a final circuit (radial or ring) and a spur off a final circuit.
On being part of the circuit and off being beyond a socket which is off the circuit.
Simples.......
- Joined
- 26 Jul 2010
- Messages
- 223
- Reaction score
- 25
- Country
The appendices at the rear of the BS 7671-2008 are informative and are excellent.
Regulation 433.1.5 does inform us that an accessory to BS 1363 can be supplied through a ring final circuit, and as your spur would most likely conform to BS 1363-4 then it is quite acceptable.
Regulation 433.1.5 does inform us that an accessory to BS 1363 can be supplied through a ring final circuit, and as your spur would most likely conform to BS 1363-4 then it is quite acceptable.
Hi all. Old thread but it goes well to answering my question so wanted to avoid starting another.
I'm currently planning for aesthetics and decor so can request what I want when the times comes where within reason minimising decor disruption.
Having read the above and the formentioned regulation appendix, I understand the following:
A fused spur can be added as part of the ring or it can be a spur of a socket that is part of the main ring that is not spurred from already. Is this correct?
Questions:
1. in the case where the fused spur is added as part of the ring, if a issue was to occur and the fuse pops, would it break the ring and therefore stop other outlets on the ring (not the spur) from working?
2 in case of the spur being inline, could I request this to be a socket combined with a fused spur I order to allow me to retain the original socket but also combine as a fused spur.
In all cases the reason for fused spur is to add extra sockets for an Standard to install in a minimal decor disruptive way.
I hope the above is clear. Any guidance appreciated.
I'm currently planning for aesthetics and decor so can request what I want when the times comes where within reason minimising decor disruption.
Having read the above and the formentioned regulation appendix, I understand the following:
A fused spur can be added as part of the ring or it can be a spur of a socket that is part of the main ring that is not spurred from already. Is this correct?
Questions:
1. in the case where the fused spur is added as part of the ring, if a issue was to occur and the fuse pops, would it break the ring and therefore stop other outlets on the ring (not the spur) from working?
2 in case of the spur being inline, could I request this to be a socket combined with a fused spur I order to allow me to retain the original socket but also combine as a fused spur.
In all cases the reason for fused spur is to add extra sockets for an Standard to install in a minimal decor disruptive way.
I hope the above is clear. Any guidance appreciated.
Correct
NO! The fuse is on the output side of the FCU. It only pops if the load on the connected side exceeds the fuse value.
Spurs are not "inline". If the Socket/FCU is "inline" then it is part of the ring. If the FCU is copnnected to a socket on the ring by a single piece of cable then that is a spur.
But, yes you can have a socket and an FCU next to each other, connected either as a spur or as part of the ring..
AFAIK a single-socket + fused-spur does not exist as a standard accessory. You might be able to make one up out of modular faceplate components, but usualy you would use a single socket + fused spur on a dual back box, which takes two single accessories and is slightly wider than a double box.
Hi thanks for the reply.
So from an aesthetic perspective, to confirm I could ask to replace the double socket on the main ring and replace with a fuse spur....And in case where the fuse should ever pop, tHe main ring will continue to work uneffected?
Generally what is better, spurring a FCU from a socket on the ring or adding the FCU to the ring (replacing the double socket in our case).
Secondly and slightly unrelated, can round junction boxes be hidden behind behind a plaster skim?
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
