routing behind skirting board

[ronald3]

Does anyone know what protection is needed for cable behind skiriting? PVC conduit, galvanised conduit or nothing at all? Would be grateful for any help. Ta

 

[plugwash]

if you are just going down from a socket nothing at all.

otherwise you need an earthed metal layer. Possible options include steel conduit, one of the screened fire resistant cable types (fp200 firetuff etc), SWA, MICC and split-concentric.

for smaller sizes the screened fire resistant cable is probablly the best option beyond that i'd say use split con if possible.

SWA and steel conduit are rather thick and MICC requires carefull termination with special tools and glands.

 

[crystal ball]

Does FP200 give adequate mech protection, cable must be enclosed in earthed metal conduit/trunking or ducting, when run out of the safe zone

 

[plugwash]

you don't need mechanical protection if you have earthed metal.

 

[crystal ball]

Not what it says in Electricians guide to the Building regs

 

[plugwash]

hmm what exactly does it say in full?

and remember thats only a guide book!

 

[plugwash]

from http://www.niceic.org.uk/downloads/concealedcables.pdf

Regulation 522-06-06
A cable concealed in a wall or partition at a depth of less than
50 mm from the surfaces of the wall or partition shall:
(i) incorporate an earthed metallic covering which complies with
the requirements of these Regulations for a protective
conductor of the circuit concerned, the cable complying with
BS 5467, BS 6346, BS 6724, BS 7846, BS EN 60702-1 or
BS 8436, or
(ii) be of insulated concentric construction complying with
BS 4553-1, BS 4553-2, or BS 4553-3, or
(iii) be enclosed in earthed conduit, trunking or ducting satisfying
the requirements of these Regulations for a protective
conductor, or be mechanically protected sufficient to prevent
penetration of the cable by nails, screws and the like, or
(iv) be installed in a zone within 150 mm from the top of the
wall or partition or within 150 mm of an angle formed by two
adjoining walls or partitions. Where the cable is connected to
a point, accessory or switchgear on any surface of the wall or
partition, the cable may be installed in a zone either
horizontally or vertically, to the point, accessory or switchgear.
Where the location of the accessory, point or switchgear can
be determined from the reverse side, a zone formed on one
side of a wall of 100 mm thickness or less or partition of
100 mm thickness or less extends to the reverse side.

notice how it always says OR not AND e.g. you only have to do one of the things listed.

 

[Adam_151]

Though if I was installing a shelf, if I hit some pyro out of zones, ok, the the earthed metal sheath will make sure the OPD is opened, but i'd be pretty ****ed off that I'd have to tear my wall open and replace it.

Metal conduit IMHO, it'll actually resist the drill

 

[brian.tabernor]

But why would you be putting a shelf on the skirting?

 

[Qedelec]

Mice need storage as well you know.

 

[Nijinski001]

or be mechanically protected sufficient to prevent
penetration of the cable by nails, screws and the like

Doesn't steel capping qualify for this?
If it does, does this mean you don't have to earth it?

 

[brian.tabernor]

Quote:
or be mechanically protected sufficient to prevent
penetration of the cable by nails, screws and the like


Doesn't steel capping qualify for this?
If it does, does this mean you don't have to earth it?

Steel capping wont prevent penetration by nails, screws or the like so doesn't conform.

 

[ronald3]

Many thanks to all for learned debate. If I go for metal channel conduit, how would I earth it? The route would involve long runs of cable around a room, with occasional vertical diversions to the sockets.

 

[Spark123]

Metal conduit is earthed at accessory boxes, however running metal conduit in imho is not really DIY. Is surface mounting out of the question? It is possible to buy plastic skirting / dado with provision to run cables in it, see http://www.tlc-direct.co.uk/Main_Index/Trunking_Pvc_Index/index.html

 

[JohnD]

Point of clarification, gentlemen: i've read and re-read plugwash's text, and it seems to mean that a drop to a light switch, or a run to a socket, needs to be in this protected earthed metal cover. Mine are under the plaster with plastic capping, which is quite common - is that not allowed any more in new builds or alterations?