Capping

[ricicle]

I see it as an interesting point that under dot and dab plasterboard no cable protection is required.

The ammendment to the regs stating that cables must now be buried 50mm in the wall would be (I assume) to stop them being damaged by the ubiquitous inch-and-a-half-eight screws.

However, if you had a wall with a cable in a bit of plastic capping running down it and you covered it in plasterboard, then that wouldn't give any protection for any screw from 3/4 inch up.

Simply sticking a screwdriver into the plasterboard and through the capping into the cable would take virtually no effort.

Surely this fouls the rule that cables should be given 'physical protection'.

What do the Pro's think?

Personally I would use metal capping - but is that the rule? Or just common sense?

Obviously metal sheathing is better than plastic but if you look at previuos posts the sheathing is only to protect from plasterers/boarders tools.
Cables are expected to run directly vertical or horizontal from accessories or in allowed zones.It is only outside these zones that a cable must be protected by an earthed metallic conduit for example

Too fast JohnD

 

[JohnD]

Hee hee!

 

[joe-90]

I see it as an interesting point that under dot and dab plasterboard no cable protection is required.

The ammendment to the regs stating that cables must now be buried 50mm in the wall would be (I assume) to stop them being damaged by the ubiquitous inch-and-a-half-eight screws.

However, if you had a wall with a cable in a bit of plastic capping running down it and you covered it in plasterboard, then that wouldn't give any protection for any screw from 3/4 inch up.

Simply sticking a screwdriver into the plasterboard and through the capping into the cable would take virtually no effort.

Surely this fouls the rule that cables should be given 'physical protection'.

What do the Pro's think?

Personally I would use metal capping - but is that the rule? Or just common sense?

Obviously metal sheathing is better than plastic but if you look at previuos posts the sheathing is only to protect from plasterers/boarders tools.
Cables are expected to run directly vertical or horizontal from accessories or in allowed zones.It is only outside these zones that a cable must be protected by an earthed metallic conduit for example

Too fast JohnD

Just to get things straight for my own benefit:

So it's still acceptable to run cables in line with sockets (vertical or horizontal) under plastic capping just under the plaster? It's only necessary to bury then 50mm when they may be (say) brought down a wall where there is no socket or whatever?

 

[JohnD]

Yes. Look up "safe zones" in your guide. You can also run them in the walls in the corner of the room. 50mm is impractical in most single or cavity walls.

If you have to protect them with an earthed metalic cover (whose purpose is not to stop the nails, but to earth them before they hit the wire so they will probably blow a fuse) then conduit is (slightly) easier to earth properly than capping.

We had a thread about giving physical protection to cables behind plasterboard a while ago, to fend off nails. Scaffold pole seemed strong enough but is probably impractical.

 

[joe-90]

I'll do that John. Thanks.

 

[sm1thson]

wow joe, since you are been nice and willing to learn something on this thread heres a link for you:

 

[joe-90]

I'm always nice and willing to learn - that's why I argue so much. The best way to learn anything is to get into a barny with those in the know. However, they have to know their stuff or they'll come unstuck.

 

[ltheb]

Sorry guys, just to clarify what JohnD referred to.. ANY metallic conduit, capping etc must be earthed just as odd lengths of pipe have to be bonded when separated by pushfit etc.
The purpose IS mechanical protection but (and I always love this!) the regs say "Note, the requirement to prevent penetration can be difficult to meet" Doh!

I'm reminded of a bloke who was working near me during a first fix using 3" wire nails coz he'd run out of plasterboard nails....!