Insulated tails used to supply flats

The way I explained this to our electrical supervisor was that the supply cable entering the flats distribution board would have to be metal conduit protected if its flush fitted, if the board is fitted to a wall the supply cable will be in the wall...

Is that me being pedantic or is this why all our new sites use armoured cables for supplies?

In general yes, but the details might catch you out. If the CUs are flush and the cable route hidden then there might be some earth steel conduit for the little part of the run to the floor or ceiling - presumably it's not easy to tell now. There's no need for the rest of the run (on the surface, under floors, above ceilings or deep in walls) to have the same treatment. There again if the CU is flushed into a decent sized void then the cable might be more than 50mm from the surface - so again side-stepping the need for RCD protection. Commonly CUs are surface mounted of course - so surface mounting the supply cable (usually in a bit of PVC trunking to make it look a bit less ugly) is quite popular, especially where it's hidden away in a cupboard.  Without seeing it, it's hard to tell - for sure the cables might be shallow and the RCD requirement overlooked, but there again it might not.


Certainly specifying SWA makes life an awful lot easier - the cable can then be run (almost) anywhere you like and conformity is just about guaranteed - and won't be called into question if things 'on site' don't go exactly to plan or if an inspector can't see everything - but that doesn't mean that the older methods are necessarily wrong.


   - Andy.

The way I explained this to our electrical supervisor was that the supply cable entering the flats distribution board would have to be metal conduit protected if its flush fitted, if the board is fitted to a wall the supply cable will be in the wall...

Is that me being pedantic or is this why all our new sites use armoured cables for supplies?

In general yes, but the details might catch you out. If the CUs are flush and the cable route hidden then there might be some earth steel conduit for the little part of the run to the floor or ceiling - presumably it's not easy to tell now. There's no need for the rest of the run (on the surface, under floors, above ceilings or deep in walls) to have the same treatment. There again if the CU is flushed into a decent sized void then the cable might be more than 50mm from the surface - so again side-stepping the need for RCD protection. Commonly CUs are surface mounted of course - so surface mounting the supply cable (usually in a bit of PVC trunking to make it look a bit less ugly) is quite popular, especially where it's hidden away in a cupboard.  Without seeing it, it's hard to tell - for sure the cables might be shallow and the RCD requirement overlooked, but there again it might not.


Certainly specifying SWA makes life an awful lot easier - the cable can then be run (almost) anywhere you like and conformity is just about guaranteed - and won't be called into question if things 'on site' don't go exactly to plan or if an inspector can't see everything - but that doesn't mean that the older methods are necessarily wrong.


   - Andy.