On Tuesday, 27 August 2019 22:53:56 UTC+1, Theo wrote:

I'm speccing up installing sockets in a brick garage. It currently has a CU
with an adjacent pair of double sockets on a short radial. I want to put some
sockets at various points around the far sides.

Because of the construction of the garage, it would be easiest to run the
wiring at head height, and run down trunking to the places where sockets are
wanted. There are roughly two options:

1. A radial around three sides, with the sockets on essentially long loops
down from the ceiling. This is just an extension of the existing radial.

2. A ring main around at ceiling level. The simplest way would be for each
socket to be spurred off, but I understand spurs aren't well received. An
alternative would be to use a variation of 1) where the ring takes a long
loop down to each socket


The natural way to do this would seem to be a ring with spurs, but if spurs
aren't recommended then a ring or radial with loops would seem a sensible
option. In that case, would it be sensible to have a long run of cable at
ceiling level, with a pair of junction boxes for each socket downlead, ie:

-----+ +----
| |
| |
socket

where + is a junction box?

Also, Part P wise, am I right in thinking that extending a radial is OK but
converting a radial to a ring is notifiable?

Finally, is it acceptable to cable-clip T&E cables (bearing in mind the new
rule to use metal clips occasionally) in an outbuilding, or is additional
protection (trunking) needed (even at ceiling level)?

Thanks
Theo

Any of those options is compliant. Rings have a slight advantage in safety & reliability over radials, and of course use thinner wire for a given rating, though more of it.

Metal cable clips: Just enough are required to stop the wiring collapsing onto someone in a fire, most clips can be plastic.


NT