Not sure I agree because adding a spur to an existing circuit is not notifiable, although as David Stone pointed out above it's not technically a spur ...

Mike

A spur being likened to the spur on a railway track, whether the spur is off a radial or a ring final circuit is not, in itself, notifiable because it is merely an addition to the circuit.

However, Mike said "Spur" which I suspected he really meant a switched (or unswitched) fused connection unit, they are often, incorrectly, called spurs and if such a thing contained a fuse then by definition in BS7671 it is a circuit. 

Take the standard Ring Final Circuit, as the name says it is a "final" circuit, however if it contains some fused connection units (say 3A example) then pedantically,the circuit (sub-circuit if you like) is actually a circuit in its own right and therefore the "Ring Final Circuit" is actually a distribution circuit insofar as the fused connection units are concerned.

As I mentioned I doubt anyone but a pedantic building officer or a heinous electrician would try take you to task on it. But they could do. Most of us would reply "Oh Get Lost!" or something

Understood, thanks.

Mike

The term "spur" can be correctly applied to a radial circuit (as well as rings) - have a look at Fig 15B on p556 of BS 7671 - the usage is probably most significant where the spur'd cable wouldn't be protected from overload by the circuit OPD (so you'd limit the load by restricting the number of outlets or downstream fusing), but it's still the same logic.

   - Andy.

Or look in the definitions where a spur is simply defined as " A branch from a ring or radial final circuit.".

I suspect any confusion arises from the misuse of "spur" when talking about a "Fused Connector Unit".

I suspect any confusion arises from the misuse of "spur" when talking about a "Fused Connector Unit".

Spot on Geoff