Which conduit?

[colin H]

Hi Folks -

Can you tell me the correct trunking/conduit to be used to protect 2.5 T and E cable in dry walled plaster ?

 

[PrenticeBoyofDerry]

You wouldn't use trunking withing dry walls and you don't really need conduit to protect your cable providing they are routed as permitted.
It's handy to have conduit to pull cables through though for such things as rewires.
You should be able to pull one 2.5mm T&E cable through 16mm oval conduit, anymore could be a bit tight. Be aware when running cables in conduit, it will effect the current carrying capacity of the cable.

 

[Lectrician]

With dry-lined walls it is common these days to simply clip the cable tight to the surface fo the wall and dot/dab over the top of them.

 

[colin H]

With dry-lined walls it is common these days to simply clip the cable tight to the surface fo the wall and dot/dab over the top of them.

Right then ! Sounds easy enough . I`m surprised at that , though . I`d have thought with all the regulations , these days , some protection would have been necessary

 

[securespark]

Not needed, UNLESS you plan to run the cables outside the prescribed safe zones.

See wiki for details.

 

[holmslaw]

..

 

[plugwash]

Afacit whether the socket outlet is flush has nothing to do with RCD requirements only whether it is "intended for general use".

This is completely orthogonal to the RCD requirements for concealed cables (which can be avoided by steel conduit, MICC or similar).

 

[ajrobb]

My understanding is there are different classes of protection:

• RCD - protects from shock by either cable penetration or misuse
  earthed conduit (or other concentric earth) - protects from shock by cable penetration (by blowing fuse on penetration)
  mechanical - prevents penetration (practically impossible)
  buried at least 50mm deep - to reduce the likelihood of penetration (some mechanical fixings for dot-n-dab need to be longer than 50mm)

AFAIK all domestic cables should have at least one of these forms of protection.

As was already pointed out, cables in conduits have lower current carrying capacity ratings. Multiple cables grouped in a single conduit can have significantly lower ratings.

There seem to be IEE Regulations and Building Regulations (Part P). I think the 30mA RCD requirement for general domestic sockets is in the IEE Regulations but not yet in Part P.

 

[ajrobb]

Sorry. I should probably said that all 'concealed' cables need protection.

 

[ban-all-sheds]

There seem to be IEE Regulations and Building Regulations (Part P). I think the 30mA RCD requirement for general domestic sockets is in the IEE Regulations but not yet in Part P.

And it never will be - the Building Regulations never go into details like that.

All that Part P says is:

Reasonable provision shall be made in the design and installation of electrical installations in order to protect persons operating, maintaining or altering the installations from fire or injury.

Sorry. I should probably said that all 'concealed' cables need protection.

colin was asking about mechanical protection. Not all concealed cables require that.