Spurs on a radial

Wait for it. Quite possibly another dull question from me, myself or I or whatever the grammer police might say.

Was doing a little investigation under the bathroom floor earlier and I've found a few spur on spurs on me socket radial circuit with god knows how many junction boxes. Think I've got more junction boxes than cable under the bathroom floor!

For all 2.5mm2 cable the big red book shows a spur on a spur (p363) then numerous sockets continuing on the main radial.

I thought you were only allowed one double socket on a spur?

If that's only rings then how many sockets can we spur off any radial and is there a limit on the use of junction boxes.

Can we do a spider arrangement off a single junction box going to two or more double sockets on any leg (supposing spiders have eight legs which i think they might do) :C

Its all down to currenty carrying capacity of the cables, for example on a 2.5 ring, the circuit protective device is 32amps. As there are 2 lots of 2.5 to every point. The reason why you can only have 1 unfused spur on a 2.5 ring is due to the fact the cable can only carry a safe max of 27amps, with 1 double socket on the end of that the max you could put through it would be 26amps.

As for a radial, you can go where ever from wherever you want. Obviously point to point is best practice and you shouldn't over load sockets with cables usually 3 max, and JB's usualy 4. But there is no limit to how many JB's you can have allthough its just not ideal, the less connections the better.

spur as much as you want

spur as much as you want

Click to expand...

...off a radial.....

...off a radial.....

Click to expand...

you would be correct this time mr ian

dooooo, A bit of additional advice here....... if those junction boxes are going to end up inaccessible you will either have to do some rewiring or replace with maintenance-free types.

be aware than you can take a spur to one point in 2.5 from a 4mm radial. you cannot then spur from this spur