Capping or no capping?

[AJshep]

Plastic capping on bare blockwork.
Oval Egatube in chases.
Always extended into the ceiling an inch and tight to the KO box, although not considered a rewireable method you can quite often attach and pull new cables down at a future date if needed.

 

[littlespark]

I don’t have much call for capping these days.

Agree that something needs to be used, not just clipped into the channel which can be a job in itself when the blocks are too hard to nail and the mortar is too soft.

A bit of plastic, or tin capping isn’t going to stop a nail or drill, but then, no one should be nailing or drilling into a safe zone directly above a switch anyway.

 

[Calebp43]

Ah, I see. When people say capping, I always think of the metal or plastic stuff that you fix over the cables, rather than oval/tube stuff that you thread the cables through (which I call conduit).

I shall have to buy a copy of guidance note 1 then, but it is the first time I have heard of problems with plaster on cables, and I have never come across any obvious damage to cables embedded direct. There is a passage in the OSG app. C warning about possible corrosion by plaster, lime, cement etc, but it is concerned with metal sheaths, conduit, armour and so on, rather than plastic cables.

Just a though - it couldn't be a typo in that text could it? If the word 'plaster' was replaced with 'plastic' the sentence would make more sense.

Ive never heard of plaster affecting the cables like that either. Someone made the point to me and referenced that..

Yeah sorry plastic I meant to say. Typing this in a hurry whilst working haha

 

[brianmoooore]

It's not just renewing or altering cables that's enabled by using round or oval conduit. How many times have you come across a burnt out socket that's damaged the last couple of inches of wire? If it's in conduit, it's often possible to gently pull down (or up) enough to get back to clean copper.
I've worked on a lot of domestic properties with walls anything up to three foot thick, so often need to position a switch well inside a door reveal. For these, I use convoluted flexible 20mm round conduit, chased into safe zones, to get up into the ceiling void.

 

[BiddeldyBwah]

Don't see the point of it. People say about it preventing plasterers nicking the cables but if they're doing that on a cable set down into a chase they're crap plasterers and i wouldn't use them anyway.

 

[nicebutdim]

Don't see the point of it. People say about it preventing plasterers nicking the cables but if they're doing that on a cable set down into a chase they're crap plasterers and i wouldn't use them anyway.

Little consolation when testing indicates a damaged cable that subsequently has to be replaced. Doesn't matter who pays for the remedials - no one wants to unnecessarily find themselves doing the same job twice.

 

[LastManOnline]

Plaster deteriorating cables? This is a new one to me

I, m obliged to run cables in wavin. I also think it,s better to have that extra layer of protection. That said I have never experienced cables damaged by plaster. Nor heard a fellow spark experience it.
Now a word about capping. Never knew it existed before joining this forum. I think it has great advantages over oval and round conduit. Running cables through oval can be time consuming and rewiring through oval can be extremely difficult.
I just completed my first kitchen renovation using capping. Have been able to leave slack in ceiling and at floor level underneath floor presses which is moving freely behind the capping and can easily be pulled up or down . It's nice to have a little insurance in case any extra slack is required in the future for heat damaged sockets etc

 

[nicebutdim]

I, m obliged to run cables in wavin. I also think it,s better to have that extra layer of protection. That said I have never experienced cables damaged by plaster. Nor heard a fellow spark experience it.
Now a word about capping. Never knew it existed before joining this forum. I think it has great advantages over oval and round conduit. Running cables through oval can be time consuming and rewiring through oval can be extremely difficult.
I just completed my first kitchen renovation using capping. Have been able to leave slack in ceiling and at floor level underneath floor presses which is moving freely behind the capping and can easily be pulled up or down . It's nice to have a little insurance in case any extra slack is required in the future for heat damaged sockets etc

Do you have a link to the Wavin product you use and is it not possible to leave slack in the ceiling with it?

 

[LastManOnline]

Do you have a link to the Wavin product you use and is it not possible to leave slack in the ceiling with it?

Of course you can leave slack in the ceiling with oval wavin but as regards being able to freely pull it down at the socket box?? Difficult at best. With the capping you are basically freeing up a significant amount of space. You in NI use round conduit which is a step up from oval. The capping I find to be a step up again.
I should confess that my capping is customised. I basically use reverse installed trunking minus the lid. It's worked a treat.
Sorry I don't have a link to hand for oval conduit but just Google it on electrical wholesalers.ie

 

[nicebutdim]

Of course you can leave slack in the ceiling with oval wavin but as regards being able to freely pull it down at the socket box?? Difficult at best. With the capping you are basically freeing up a significant amount of space. You in NI use round conduit which is a step up from oval. The capping I find to be a step up again.
I should confess that my capping is customised. I basically use reverse installed trunking minus the lid. It's worked a treat.
Sorry I don't have a link to hand for oval conduit but just Google it on electrical wholesalers.ie

This stuff? Have to say I detest oval conduit for the very reasons you describe and all this time I thought round conduit was used in IE!

Your custom made capping would certainly leave more space than usual to pull slack through. I take it you're familiar with the stuff commonly used in GB?

 

[LastManOnline]

This stuff? Have to say I detest oval conduit for the very reasons you describe and all this time I thought round conduit was used in IE!

Only advantage of oval conduit over round is the shallower chase required. After that it's all disadvantages.

. I take it you're familiar with the stuff commonly used in GB?

No.Have yet to order some

 

[nicebutdim]

No.Have yet to order some

It's very shallow, with a wide edge - the only place I've seen used was on poorly installed pvc windows, where a large window was replaced with two small units and this capping was siliconed over the join. Never seen it used over cables.

 

[BiddeldyBwah]

Little consolation when testing indicates a damaged cable that subsequently has to be replaced. Doesn't matter who pays for the remedials - no one wants to unnecessarily find themselves doing the same job twice.

Someone would have to be unfathomably horrendous at their job to damage a cable to the extent that it needs replacing in that situation. I'm struggling to imagine how one would even manage to do that with a trowel (especially a worn in one) even when purposefully trying to do it. Non issue in my opinion and imo capping is just unnecessary.

 

[nicebutdim]

Someone would have to be unfathomably horrendous at their job to damage a cable to the extent that it needs replacing in that situation. I'm struggling to imagine how one would even manage to do that with a trowel (especially a worn in one) even when purposefully trying to do it. Non issue in my opinion and imo capping is just unnecessary.

I also feel that capping is unnecessary and have stated many times that round conduit is my preferred method of containment, where cables are to be buried in walls.

 

[BiddeldyBwah]

I also feel that capping is unnecessary and have stated many times that round conduit is my preferred method of containment, where cables are to be buried in walls.

Is that what you do in Ireland?

I find that weird that people would feel cable needs containment at all. The outer sheathing is there for a reason otherwise we'd all just use singles.

 

[telectrix]

I don’t have much call for capping these days.

Agree that something needs to be used, not just clipped into the channel which can be a job in itself when the blocks are too hard to nail and the mortar is too soft.

A bit of plastic, or tin capping isn’t going to stop a nail or drill, but then, no one should be nailing or drilling into a safe zone directly above a switch anyway.

but then, no one should be nailing or drilling into a safe zone directly above a switch anyway.

so when is somebody going to tell Kevin Kitchen fitter that?

 

[littlespark]

Would kev the kitchen stop drilling when his drill starts making that ting ting ting sound as it bounces off any capping?

Nooooo…. Just keep going

 

[BiddeldyBwah]

Would kev the kitchen stop drilling when his drill starts making that ting ting ting sound as it bounces off any capping?

Nooooo…. Just keep going

I'm not up to date on domestic regs but i thought the RCD protection was what mattered? Still don't see much use for capping when it can just be drilled through and is RCD protected.

 

[pc1966]

I'm not up to date on domestic regs but i thought the RCD protection was what mattered? Still don't see much use for capping when it can just be drilled through and is RCD protected.

Yes, in most cases if the cable is not at least 50mm deep then RCD protection is needed (exceptions being the likes of SWA or cables to BS 8436 or IS 273 standards such as Flexishield).

Metal capping is not enough. If it were reliably earthed then it would allow safe disconnection without a RCD, but that is not likely. Traditional metal conduit would do, as it is designed to be the system CPC anyway.

The on-site guide suggests at least 3mm thick steel is needed for physical protection of cables. Even then I feel that it should be properly earthed as somebody could still penetrate it with a power tool and lack of care (or maybe nail-gun?) and having a large chunk of buried metal go live is I suspect worse. So my own choice would be plastic & RCD as most domestic circuits need that anyway.

 

[Deleted account]

A fifth option. It depends.
I did put no needed, but only if I am doing a light skim covering of my cables. If someone else is working around my cables after me and covering them I’d want to protect them From light tools and trowels.

its real easy to slice through insulation with a trowel. Ive done it myself.