My new home and Part P

[Paul_C]

Indeed so. Part 2 of the 17th Ed defines a spur as 'a branch from a ring or radial final circuit'. However,as mentioned earlier, Appendix 15 does not use the word spur in relation to a branch of a radial circuit wired in the same size cable as the rest of that circuit.

Seems like another weird change for the 17th edition then.

But as far as the original question is concerned, it doesn't matter whether it's the traditional spur run from a socket on a ring, or a new branch (whether one wishes to call it a spur or not) from a socket on a radial circuit, it's still just adding a socket to an existing circuit, so if not part of a "special installation" nor in a "special location," it's not notifiable.

 

[JohnW2]

But as far as the original question is concerned, it doesn't matter whether it's the traditional spur run from a socket on a ring, or a new branch (whether one wishes to call it a spur or not) from a socket on a radial circuit, it's still just adding a socket to an existing circuit, so if not part of a "special installation" nor in a "special location," it's not notifiable.

Agreed.

Kind Regards,

 

[ebee]

yes I think we are all pretty much in agreement without any conflict on this one.

Ring or radial a spur is a single cable having a csa smaller than the main conductors (or the sum of main conductors csa in the case of a ring).

Perhaps someone might like to tidy up my definition though

 

[JohnW2]

yes I think we are all pretty much in agreement without any conflict on this one.
Ring or radial a spur is a single cable having a csa smaller than the main conductors (or the sum of main conductors csa in the case of a ring).
Perhaps someone might like to tidy up my definition though

Yes, I think it's all clear and agreed.

In the case of an RFC, if you wanted to have a definition that was totally exhaustive, I guess you'd have to cater for the (incredibly unlikely) possibility that someone decided to wire a 'spur' with cable that had a CSA equal to or greater than the sum of the CSAs of conductors in the ring (which, in practice, would mean 6mm²). I would still regard that as a spur, even though it would not be with the (very reasonable) definition you have suggested.

More to the point, I think that a 4mm² or even 6mm² spur off a 2.5mm² RFC should still be limited to one socket, if unfused, or to 13A if fused - since I would think that the restrictions are as much to do with limiting point loadings on the main ring than the CCC of the cable with which the spur itself is wired.

Kind Regards, John.

 

[ban-all-sheds]

Think how many problems just go away if you don't use ring finals and don't branch off radials with a reduced size cable...

 

[ebee]

Aww Ban,
trust you to spoil it all by doing away with the good old British Ring Final!



You are being far too sensible, it's good to have to think a little now and again and keeping the good old ring will keep us thinking.

Some of us were brought up on rings yer know!
We eat' sleep & drink rings,
yer canna do away with them.

(Like that silly cartoon someone showed us were you can't be a good electrician if you don't do rings ).

Actually, joking aside now, I am sure that some people actually do think like that.

Seriously though, I do rings, they do have their place (and problems OK I know)

 

[JohnW2]

Think how many problems just go away if you don't use ring finals and don't branch off radials with a reduced size cable...

Spoil sport! It's the RFCs which create most of the fun

RFCs are one of those things (like tobacco and alcohol) which would probably have been instantly banned had they first been thought of in recent times! Mind you, the same might even be true of multiple sockets on the same circuit (of whatever design) - which, in true engineering terms, is (in conjunction with 'plug-in' loads) probably the thing that most compromises 'proper design' of electrical installations!

Kind Regards, John.