Cable Capping is NOT required and DOESN'T protect

[Piratepete]

Hi Guys :yawn:
This is my understanding about the use of capping,

1. Cable Capping is not designed to protect against nails, but to protect the cable from the plasterer's trowel on traditional plastered walls and particularly aggressive lime based plasters.
Neither the steel version nor the plastic (which I will occasionally use) will protect against nails.

In fact, only steel conduit, steel trunking or SWA (steel wire armoured) cable are considered by BS7671 to offer adequate mechanical protection against nails and such like.

2. Where walls are being dabbed (or battened) and boarded on top of the cable it follows that capping is not required - I put in a enough clips to keep the cable straight and supported.

3. If I'm doing a rewire I'll cut a chase no wider than the cable and make sure it's clipped down below the surface - less work for the plasterer and less for me and less mess for the householder.

Has anyone got any problems with this?

Cheers
Pete (p'd off because on latest batten and board job, plasterer first complained about the lack of capping and then managed to put a nail straight through an armoured cable! Point made! Using a nail gun I think.)

 

[GLENNSPARK]

Hi Guys :yawn:
This is my understanding about the use of capping,

1. Cable Capping is not designed to protect against nails, but to protect the cable from the plasterer's trowel on traditional plastered walls and particularly aggressive lime based plasters.
Neither the steel version nor the plastic (which I will occasionally use) will protect against nails.

In fact, only steel conduit, steel trunking or SWA (steel wire armoured) cable are considered by BS7671 to offer adequate mechanical protection against nails and such like.

2. Where walls are being dabbed (or battened) and boarded on top of the cable it follows that capping is not required - I put in a enough clips to keep the cable straight and supported.

3. If I'm doing a rewire I'll cut a chase no wider than the cable and make sure it's clipped down below the surface - less work for the plasterer and less for me and less mess for the householder.

Has anyone got any problems with this?

Cheers
Pete (p'd off because on latest batten and board job, plasterer first complained about the lack of capping and then managed to put a nail straight through an armoured cable! Point made! Using a nail gun I think.)

any problems with what?...

 

[cornishboy]

We always use oval conduit in Cornwall it always been the local way of doing flush work.
Conduit is normally fixed to the back of the chase with galv clout nails, at least you have some chance of rewiring, conduit is normally squashed to go into the 20mm hole, we hardly eve use capping down here

 

[Adam W]

:yawn: When doing a rewire if capping or oval conduit was previously used you can sometimes pull the cable out and pull a new one in without having to chase the wall.:sleep1:

 

[NickD]

In fact, only steel conduit, steel trunking or SWA (steel wire armoured) cable are considered by BS7671 to offer adequate mechanical protection against nails and such like.

Is SWA considered to offer sufficient mechanical protection? Not that I've tried but I suspect a nail might push the strands aside and breach the armour. I recall it says the mechanical protection standard is considered difficult to meet. It's a moot point because the armour should be earthed and then it's contained in an earthed containment system which is the other way of meeting the no-RCD-needed criteria?

 

[GLENNSPARK]

Is SWA considered to offer sufficient mechanical protection? Not that I've tried but I suspect a nail might push the strands aside and breach the armour. I recall it says the mechanical protection standard is considered difficult to meet. It's a moot point because the armour should be earthed and then it's contained in an earthed containment system which is the other way of meeting the no-RCD-needed criteria?

and for TT?

 

[Darkwood]

Capping as you point out is for protection only from the plasterer ... ps you forgot MICC on your list of mechanically protected cables, also if supplying sockets you still require RCD protection but can be afforded at the outlet provided your not abusing the exclusion regulation which in the up-coming amendments will be harder to implicate.

 

[NickD]

and for TT?

Don't understand where you're coming from, sorry. I'm just talking about burying cables in walls.

 

[GLENNSPARK]

would you not be using an RCD for SWA on a TT?

 

[NickD]

Aside from the general requirement for RCD on TT, I don't see what specifically the relevance of the SWA is, feel free to enlighten me.

 

[GLENNSPARK]

bottom sentance in post #5

"It's a moot point because the armour should be earthed and then it's contained in an earthed containment system which is the other way of meeting the no-RCD-needed criteria? "

if its TT an swa would be needing an RCD...wouldn`t it....as its still may be the only way that times would be met...

 

[NickD]

if its TT an swa would be needing an RCD...wouldn`t it....as its still may be the only way that times would be met...

Yes but that's nowt to do with it being steel armoured, just to do with it being TT. The earthed containment the SWA provides (and the mechanical protection, if SWA is deemed mechanical protection against nails, which is what I was asking) gets you out of the need to have additional protection from an RCD what with it being buried 50mm in the wall. It can't get you out of the need to have fault protection from an RCD what with that being the only way you can meet the disco times​. Is that clearer?

 

[GLENNSPARK]

Yes but that's nowt to do with it being steel armoured, just to do with it being TT. The earthed containment the SWA provides (and the mechanical protection, if SWA is deemed mechanical protection against nails, which is what I was asking) gets you out of the need to have additional protection from an RCD what with it being buried 50mm in the wall. It can't get you out of the need to have fault protection from an RCD what with that being the only way you can meet the disco times​. Is that clearer?

lol...you dont need to explain it to me nick....lol..

it was just where you had stated about the no RCD criteria.....so i thought i`d throw a bit of TT into the mix....lol...

 

[NickD]

lol...you dont need to explain it to me nick....lol..

it was just where you had stated about the no RCD criteria.....so i thought i`d throw a bit of TT into the mix....lol...

I did wonder if you were just pulling my plonker. Now wash your hands.

 

[shanky887614]

Hi Guys :yawn:
This is my understanding about the use of capping,

1. Cable Capping is not designed to protect against nails, but to protect the cable from the plasterer's trowel on traditional plastered walls and particularly aggressive lime based plasters.
Neither the steel version nor the plastic (which I will occasionally use) will protect against nails.

In fact, only steel conduit, steel trunking or SWA (steel wire armoured) cable are considered by BS7671 to offer adequate mechanical protection against nails and such like.

2. Where walls are being dabbed (or battened) and boarded on top of the cable it follows that capping is not required - I put in a enough clips to keep the cable straight and supported.

3. If I'm doing a rewire I'll cut a chase no wider than the cable and make sure it's clipped down below the surface - less work for the plasterer and less for me and less mess for the householder.

Has anyone got any problems with this?

Cheers
Pete (p'd off because on latest batten and board job, plasterer first complained about the lack of capping and then managed to put a nail straight through an armoured cable! Point made! Using a nail gun I think.)

I don't agree with 2.

If you have more than one cable plastic capping is a lot quicker.

 

[7029 dave]

On my rounds yesterday,guy 1st fixing a bunglow, running in oval conduit for his switch drops, running short a good 1.5" at top of celling and at the switch box, whats the point of using it?, will never be able to pull through in future, that winds me up.!!

 

[Piratepete]

Is SWA considered to offer sufficient mechanical protection? Not that I've tried but I suspect a nail might push the strands aside and breach the armour. I recall it says the mechanical protection standard is considered difficult to meet. It's a moot point because the armour should be earthed and then it's contained in an earthed containment system which is the other way of meeting the no-RCD-needed criteria?

As usual, this thread has digressed in the usual interesting ways! In my last line, I said that the plasterer had indeed put a nail through the SWA (dead short live/earth and the swa is earthed). So much for providing mechanical protection!

Pete

 

[shanky887614]

As usual, this thread has digressed in the usual interesting ways! In my last line, I said that the plasterer had indeed put a nail through the SWA (dead short live/earth and the swa is earthed). So much for providing mechanical protection!

Pete

There still nailing them down your way?

Here either use bonding to stick it to wall or wooden batterns first then screwed with impact driver

 

[Piratepete]

We always use oval conduit in Cornwall it always been the local way of doing flush work.
Conduit is normally fixed to the back of the chase with galv clout nails, at least you have some chance of rewiring, conduit is normally squashed to go into the 20mm hole, we hardly eve use capping down here

Yeah, but you're still using cotton covered rubber insulated single cores in Cornwall, aren't you, which are ideal for conduit.

Pete

 

[shanky887614]

Yeah, but you're still using cotton covered rubber insulated single cores in Cornwall, aren't you, which are ideal for conduit.

Pete

Get a map mate it might be usefull. Im in THE EAST MIDLANDS

MIDLANDS = MIDDLE

NOWHERE NEAR CORNWALL

plasterer's don't use nails now

 

[Engineer54]

SWA cable has no protection from nails or screws being driven through it. It's mechanical protection is in the form of impact or to a certain degree crushing protection. SWA does however have an earthed containment and will in the majority of cases take out the supplying protective device where a metallic object penetrates the sheath and armouring through to the live conductors...