Capping or no capping?

[Calebp43]

Do you use capping to protect your cables? I recently watched a YouTube video explaining why you should use capping to protect your cables. I personally don't think it's needed for the following reasons;

- it's not in the regs. Although there are things in the regs saying to protect the cable from environmental factors and mechanical protection, it never says to use it. You could make a case for the regs implying too use it but I think it would be a poor case.

- very little extra mechanical protection, if any!

- a lot more time consuming.

- It's more expensive. this can be a real factor for a lot of people. Not a lot of people have the money for a rewire and adding that extra cost could be the difference.

But on the hand it does have its benefits;

- easy to replace cables. If that leg has an issue it's much easier to replace that leg or repair it when the cable has been capped all the way to the box.

- metal capping has more mechanical protection.

- prevents plaster deteriating cables.

All things considered when the choice is mine I think I will put it as an option for the customer for a fee of course, listing the pros of having it.

I'm an apprentice. Should be qualified next year. I would really value your opinions on why I should or shouldn't use capping. I've worked for 3 sparks and neither one have used capping. So I've only ever really heard one side of the argument. Thanks in advance.

 

[Calebp43]

If already chasing deep enough, I'd go the few extra pence on round pvc conduit and female bushes. Much easier to get cables through.

Can't really argue with that. Easier than oval I would assume. How would you fix it in the chase? All round band or something?

 

[Pretty Mouth]

This is why I have been taught to chase in deep enough so the trowel doesn't hit. Use the full length of the grinder.

Yes it is easier to replace the cables this way MOST of the time if done correctly. That is with oval conduit though. I should've been more specific.

Mechanical protection is provided with metal conduit. Again that's me not being specific, I assumed you'd pick up what I meant.

Yeah the plaster deteriating was something I literally learned quite recently. Take a look at guidance note 1 - 4.7 materials likely to cause such attacks include:
Plaster coats containing corrosive Salts: lime, cement and plaster.
Some examples of this
Placticisers migrate to ploystyrene from thermoplastic and also other types of plaster (see 7.5 also)

That's fair enough. I have never done it but I've been doing this for 3-4 years only and worked with 3 separate sparks whove never done it. I would be curious to see if it really is quicker because most people I speak to on this tell me that it takes a lot longer.

Thanks for taking the time to create a detailed comment.

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.

 

[SparkySy]

I don't think modern Plaster is as harsh on cables. The older lime Plaster and the likes was more of an issue. (Don't quote me on this) But still I would put some containment round it!

 

[DPG]

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.

Agree - I suspect a typo there.

 

[7029 dave]

I like to use oval conduit on my first fix, however depending on the situation nothing sometimes.

 

[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?