Flex for 13a sockets ?

[johnad]

I would just like to satisfy my own curiosity after seeing sockets wired in 2.5mm flex rather than cable.
I work in a major retail store and we are undergoing some big alterations
I watched with interest that the sparks are installing all the new power using 2.5 3 core flex, I have never seen this done before and wondered if this was now a standard practice ?
The few sockets I have managed to see during the work are not on a ring and all wired back to the fuse board in white 3 core flex
Where the wireing is under the floor or running down from the ceiling it is protected in plastic conduit with all the overhead runs running on cable trays.
All the existing wireing is in singles inside steel conduit but all the new fuse boards are full of this white flex
I'm not asking if this is right as it obviously is the new way to do things but why ?
Is it just a cost thing?

 

[OwainDIYer]

It might not be flex (I would be rather concerned if it were).

Probably some form of circular cable chosen for fire-retardency and/or having an earthed screen which means it doesn't have to be RCD protected.

 

[ericmark]

It could be Ali-tube cable which does look like flex but there is not reason not to use flex and it would mean larger earth wires are used. However flex is more expensive than twin and earth so unlikely.

Ali-tube to BS 8436 does not need RCD protection and is more resistant to fire than twin and earth plus it can be trimmed very like mineral insulated giving a very neat job. Mineral insulated looks similar to Ali-tube but needs very special glands and even more fire resistant than Ali-tube.

 

[333rocky333]

tesco use YY cable a lot, though its normally grey colour, fp200 is also quite common in there stores, this is white and could at a glance look like flex though it has a bare earth

I assume its cheaper and quicker to install

 

[johnad]

Yes I may be wrong calling it flex it may well be some kind of fire rated wiring I will have to try and find out exactly what it is.
Yes it is at a tesco store but the earth wire is not bare and it has no special glands etc .
I'm back at work tomorrow so I will have a better look and maybe try and get a couple of pics
Thanks guys

 

[333rocky333]

Usually theres a code and or a bs number embossed on the outer sheath, this will denote the cable

Standard flex did tend to be used in some of the smaller express stores, though as said previously its normally YY cable now.

If you want to PM me the store number, as were one of the main contracters for TESCO and possibly doing the refresh,

Bear in mind its possible the sales floor sockets may not actually go back to the board and possibly just flexed to a bus bar tap off within the ceiling void

Have you had your new LED lights yet

 

[DaftPunk]

I've worked on some large sites recently where all the final circuits are wired in standard flex. All the lights are wired using pre made flex 7 leads and marshalling boxes laid in basket with no on site terminations made at all.

 

[DaftPunk]

I've worked on some large sites recently where all the final circuits are wired in standard flex. All the lights are wired using pre made flex 7 leads and marshalling boxes laid in basket with no on site terminations made at all.

 

[johnad]

I did try to get a couple of pics today but they have come out a bit dark but I have managed to have a better look and it is YY flex that was used.
So how exactly is this different from normal 3core flex ?
And how many sockets are permitted on a single cable run as I did notice 4 doubles on one I thought there was a limit on outlets not on a ring ?
As I said in my opening post I'm just interested as I have never seen things done this way before.
(Or maybe I just have to much time on my hands lol)