what is maximum amount of spur sockets taken from a main , the main amperage can be changed easily the wiring is 2.5 and a ring main is not possible without a lot of work as this is a large old house which has been wired this way , there will only be one large consumer a water heater .
1 spur per socket on the RFC See Appendix 15 BS 7671
As many as you see to be sensible with a 4mm twin and earth spurring off? I could be wrong, I'm not going to the van at this time for the BYB.
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Ignore me then. Thank you for correcting me fellas.
There's no limit on the number of spurs on a ring. But not more than one accessory is allowed on any unfused spur.
If you have a ring final circuit then the recommendation is that the number of unfused spurs does not exceed the number of point on the ring. e.g. with ten sockets of the ring a maximum of 10 unfused spurs is recommended. The number of fused spurs is unlimited.
An unfused spur will only supply a single point of use.
In practice you would be looking at the ring loading and ensuring that there were not a concentration of current drawn at one point of the ring.
An unfused spur will only supply a single point of use.
In practice you would be looking at the ring loading and ensuring that there were not a concentration of current drawn at one point of the ring.
I'm clearly missing something here, as both you and Pete999 have mentioned this. I can't find anything in the current edition of the regs about a limit on number of spurs, although maybe I've read it in a previous edition.
As I say it is a recommendation not a regulation.
It is mentioned in the OSG under standard circuits.
Having re-read the OP, I'm not sure we're talking about a ring....
"what is maximum amount of spur sockets taken from a main , the main amperage can be changed easily the wiring is 2.5 and a ring main is not possible without a lot of work as this is a large old house which has been wired this way"
I think he's talking radial.
"what is maximum amount of spur sockets taken from a main , the main amperage can be changed easily the wiring is 2.5 and a ring main is not possible without a lot of work as this is a large old house which has been wired this way"
I think he's talking radial.
Yes. Can you tell me where in Appendix 15 this is referred to?
Thanks. Can't find my OSG at present.
I have found it in the 15th edition, Appendix 5, paragraph heading "Spurs".
Just found my OSG. Yes, 7.2.2, still retains this clause. Looks like it's out of step with the current regs.
Interesting you could well be right. With main I assumed ring main.
If it is a radial then spurs are not possible, only branches, which are also unlimited though again recommended to be minimised (I think).
A 20A radial could be run all over the place without overloading a 2.5/1.5 mm² cable, though a large house circuit may experience nuisance tripping.
Between App 14 and App 16 Sorry couldn't resist Page 453 in my copy
Sorry mate I misread your post, off hand no I can't but it's not a very big appendix 3 or 4 pages most of the appendix is diagrams
Appendix 15 is two pages. One on rings and one on radials. There's no reference to number of spurs off a ring.
You are correct it doesn't, but the OSG is what it is a guide BS7671 is a regulation and imo if someone is in doubt about something, the OSG is where to go and look.
OK, your choice.
It's a bit odd that the OSG adds a requirement that isn't present in the regs. My guess is that it's a hangover from the 15th edition and the writers of the OSG haven't noticed that the requirement has been removed from the regs.
So are you saying that as an example 10 sockets in a RFC you can't have 10 sockets as unfused spurs?
No. I'm saying you can have as many unfused spurs on a ring as you like, irrespective of the number of sockets on the ring. I believe that this complies with the current regs.
Yes Handy I can see where you are coming from now, well you live and learn
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