capping cables

C

citybluesmith

hi .today i have just finished re wiring a house.i asked a more experienced spark to come and have a look and check it for me.he said that i needed to cap all my cables.i have checked the regs and my cables are ok due to being in zones.is he right ? cheers
 
There is no need to cap unless it is in steel for a reason, it is good practice to cap in plastic and can make future cable replacement easier. But it is only there to protect the cables from the dreaded plasterer and his float. I chase them in and clip to the wall and slap a bit of bonding plaster in to keep them out of trouble,unless the spec says fit capping.

Cheers........Howard
 
cables are only capped to stiop them beinmg damaged by the plasterers trowel. think about it, caopping is fixed down with nails, so its not going to offer any protection from drills ect. theres no regulation saying they have to be capped, but its good practice. in chases where only the chase is to be filled, (the rest of the wall is already plastered) i dont bother with capping, but others probably will.
 
had a building inspector last year, refused to pass a job where cables were clipped. and that was a job where all the walls were to be dry lined. i asked him to quote the regulation ( either electrical or building regs) which stated they had to be capped. after phoning his office he went off with the hump. different guy the next day said " no problem"
 
I like to use oval - I've had plasterers damage cables and not mention it, and then when it's all plastered and finished and you do your second fix, it's YOUR bloody fault and you have to pay for it to be sorted. Also, it looks much tidier, if there IS a problem tou can pull through new cables, and you can get away with a clip in the top, a clip in the bottom, and everythings nice and neat.

I used to use top hat but I always managed to get it all twisted and rubbish, always thought it looked ruff in the jungle. Also, you need really wide chases.

However, back to the question, no there's no reg saying you should, ALSO being directly plastered will give it a higher current carrying capacity.
 
rocker said:
I like to use oval - I've had plasterers damage cables and not mention it, and then when it's all plastered and finished and you do your second fix, it's YOUR bloody fault and you have to pay for it to be sorted. Also, it looks much tidier, if there IS a problem tou can pull through new cables, and you can get away with a clip in the top, a clip in the bottom, and everythings nice and neat.

I used to use top hat but I always managed to get it all twisted and rubbish, always thought it looked ruff in the jungle. Also, you need really wide chases.

However, back to the question, no there's no reg saying you should, ALSO being directly plastered will give it a higher current carrying capacity.
Click to expand...

Hence the reason that I was taught to ALWAYS do a continuity and IR test, after first fix, and before you do your second fix mate.
 
telectrix said:
had a building inspector last year, refused to pass a job where cables were clipped. and that was a job where all the walls were to be dry lined. i asked him to quote the regulation ( either electrical or building regs) which stated they had to be capped. after phoning his office he went off with the hump. different guy the next day said " no problem"
Click to expand...
Love it! :)
 
I aways cap my work up new builds or re wires, in my opinion i just looks tidy and a good job done.
 
Does it matter what it looks like if it is going to be plastered over?

I clip on put some bonding plaster over it to hold it in place and give some protection.
 
Bit excessive I know but lately I've been using 20mm conduit and female connectors into the backboxes. It looks really neat and makes the circuit easy to modify later if you need to add a socket, additional switchwire, spur or whatever, or like mentioned above, you have to do a last minute repair to a damaged cable. Used to use oval and grommets but never liked the way the flat conduit doesn't line up with the round knockout.
 
I prefer your way of using conduit and connectors to, for the very reasons you have explained here...
 
When I was in Northern Ireland, all wiring was in plastic 20/25mm conduit...it made 1st fix a bit like hard work but was better in the long run.
 
We cap all our cables, it's definitely peace of mind like people have said about protection from plasterers etc.

Also, my NVQ man said the main reason for capping is in fact to give the cables a bit of air for heat loss... I never knew that.
 
I think you're all missing the point about capping.....It offers very little mechanical protection and as has been mentioned before most cables should be ran in "safe zones". Since the 17th edition requires the household to be protected with a 30mA main rcd for premises being used by "normal persons", then the cables are protected to a very high standard/disconnection time. However, this cannot foresee future alterations, e.g. a faulty main rcd at the consumer unit being replaced with a 2 pole main switch by "a friend of a friend"! thus creating in one fell swoop a dangerous installation.......This is where mettalic capping over buried cables which has been EARTHED to the nearest socket will still be adequate as it will give EEBADS. As for using plastic capping for cables buried in plastered walls.....I wouldn't dream of using any form of PVC containment in buried walls as it provides absolutely no mechanical protection and has no value where EEBADS is concerned!!! So it is just a costly non-starter to use pvc containment in plastered walls and the two previous methods are the best practise and safest methods that have passed the test of time.
 
metallic capping is useles as regards penetration by nails or screws, hardly any better than plastic. if you are going down the route of earthed metallic protection, you're talking galv. steel conduit, thus necessitating deep chases and bonding. best cost effective method is oval tube. and btw, it's not eebads any more.
 
telectrix......"metallic capping is useless as regards penetration by nails or screws".........And your point is exactly? This is why it has to be earthed as it provides no other protection other than ADS. And yes I did quote EEBADS from the 16th edition as I believe it is better practise to continue this practise rather than relying on an rcd for sole protection for disconnection times! And I also think you've gone way of course bringing metallic conduit into the discussion, and as for pvc oval conduit.......there is no need for it if you are running cables in "safe zones" and the household is protected with a main rcd, and the cables that might be deemed to have a greater degree of risk have been covered with earthed metallic capping! I know I'm only an Approved Electrician with 20 years experience and a full apprenticeship behind me not to mention having worked in all sectors of the electrical industry and passed all the required courses to keep up to date with regulations etc. But who am I? I'm just another daft spark that's watching his trade being watered down and good working practise being laughed at!!!
 
my point is that the wafer thin metal capping is insufficient mechanical protection against nails and screws as they go right through it. sorry about the eebads comment. when i read your post i did not know whether or not you were qualified . was not trying to have a go at you.
 
madmac said:
I know I'm only an Approved Electrician with 20 years experience and a full apprenticeship behind me not to mention having worked in all sectors of the electrical industry and passed all the required courses to keep up to date with regulations etc.
Click to expand...

Since when did we start posting our qualifications and experience as part of our argument.
I doesn't help the debate one bit.

I should know I've been posting on forums for over 125 years and have a degree on the subject.
 
Cheers telectrix, sorry about the rant also but as I said I despair at the way the whole industry seems to be heading. You are correct about metallic capping having insufficient mechanical protection and that is my point, it was not intended for that purpose, it was intended to provide EEBADS so that if a "safe zone" was breached with a nail or screw it would first have to pass through the earthed metallic capping before hitting the live cable and thus earthing the nail or screw instantaneously and causing Automatic Disconnection of the overload protective device thanks to Earthed Equipotential Bonding. I know the 17th now says this is not required anymore due to the sensitivity of rcd protection but as I said what if the rcd fails or is replaced with just a 2 pole main switch? Where is the protection for a vulnerable buried pvc insulated cable? It is good practise and costs buttons and takes minutes to install and also gives you peace of mind.
 
I only ever cap me cable if the cahses are being left unfilled for a while, someone else is doing the plastering afterward or if its a new build where the cables will be left exsposed until the wall is plastered
 
madmac said:
Cheers telectrix, sorry about the rant also but as I said I despair at the way the whole industry seems to be heading. You are correct about metallic capping having insufficient mechanical protection and that is my point, it was not intended for that purpose, it was intended to provide EEBADS so that if a "safe zone" was breached with a nail or screw it would first have to pass through the earthed metallic capping before hitting the live cable and thus earthing the nail or screw instantaneously and causing Automatic Disconnection of the overload protective device thanks to Earthed Equipotential Bonding. I know the 17th now says this is not required anymore due to the sensitivity of rcd protection but as I said what if the rcd fails or is replaced with just a 2 pole main switch? Where is the protection for a vulnerable buried pvc insulated cable? It is good practise and costs buttons and takes minutes to install and also gives you peace of mind.
Click to expand...


You make some very good arguments here and in your previous post on this thread. I am in complete agreement with you on the good installation practices of our industry being watered down too. Far too much reliance is now being given over to RCDs to provide protection. Perhaps no-one takes any notice of the almost daily posts here, and on other forums, of the failures afforded to these RCD devices...
 
It used to be that capping was recommended, as the plaster had an adverse effect on the cables.
 
but we don't use lime and hore hair any more, though i hear they are trying to promote the use of horse hair at newbury.
 
madmac said:
I think you're all missing the point about capping.....It offers very little mechanical protection and as has been mentioned before most cables should be ran in "safe zones". Since the 17th edition requires the household to be protected with a 30mA main rcd for premises being used by "normal persons", then the cables are protected to a very high standard/disconnection time. However, this cannot foresee future alterations, e.g. a faulty main rcd at the consumer unit being replaced with a 2 pole main switch by "a friend of a friend"! thus creating in one fell swoop a dangerous installation.......This is where mettalic capping over buried cables which has been EARTHED to the nearest socket will still be adequate as it will give EEBADS. As for using plastic capping for cables buried in plastered walls.....I wouldn't dream of using any form of PVC containment in buried walls as it provides absolutely no mechanical protection and has no value where EEBADS is concerned!!! So it is just a costly non-starter to use pvc containment in plastered walls and the two previous methods are the best practise and safest methods that have passed the test of time.
Click to expand...

madmac said:
telectrix......"metallic capping is useless as regards penetration by nails or screws".........And your point is exactly? This is why it has to be earthed as it provides no other protection other than ADS. And yes I did quote EEBADS from the 16th edition as I believe it is better practise to continue this practise rather than relying on an rcd for sole protection for disconnection times! And I also think you've gone way of course bringing metallic conduit into the discussion, and as for pvc oval conduit.......there is no need for it if you are running cables in "safe zones" and the household is protected with a main rcd, and the cables that might be deemed to have a greater degree of risk have been covered with earthed metallic capping! I know I'm only an Approved Electrician with 20 years experience and a full apprenticeship behind me not to mention having worked in all sectors of the electrical industry and passed all the required courses to keep up to date with regulations etc. But who am I? I'm just another daft spark that's watching his trade being watered down and good working practise being laughed at!!!
Click to expand...

As soon as I read these wildly differing quotes I had to respond to this. As for your 20 years in the trade your still a boy at it.

Having trained down a coal mine, worked in hospitals, factories, high rise buildings, petro chemical plants, etc, etc etc and domestic homes I can safely say that unless the designer for some unknown reason insisted on it, I have yet to see buried T+E cable in a domestic situation run in earthed metalic capping, and that is before the advent of RCD being used for additional protection.

I have indeed run metal conduit in a domestic home as the designer wanted it, and the designer get's what he wants, but be assured I would never design a domestic home using earthed metal anything unless there was a very good reason to. And that is not a deteriation in standards that is common electrical practice.
 
i did think of screwing zebedees into the shoes, be good for over the sticks races.
 
Colin Integrale said:
We cap all our cables, it's definitely peace of mind like people have said about protection from plasterers etc.

Also, my NVQ man said the main reason for capping is in fact to give the cables a bit of air for heat loss... I never knew that.
Click to expand...

I think your NVQ man made that up Colin - you get better heat dissapation if the cable is buried directly in the plaster!

Having said that I like to use plastic conduit with adaptors into the boxes - slight higher cost but I've been more than happy on occasions when cables been damaged by other trades (or even the apprentice).
 
Last edited:
Sometimes certain things aren't in the regs but then surely it depends on the client specification, if your doing a rewire or new build and you don't have to have capping because its in safe zones or on a rcd but the client requests mechanical protection to be installed then surely that it was you do.

Sent from my HTC Desire using Tapatalk
 
malcomsanford: I never stated that metallic conduit is never used on domestic dwellings I was simply pointing out that telectrix had missed my point entirely about using earthed metallic capping for added protection of cables buried in plaster and deemed to be at a greater risk than other cable routes. I also mentioned my experience because it helps to know with whom you are talking to in respects to technical knowledge or lack of it, and just because you have never seen metallic capping being used doesn't mean that it's wrong or going over the top to use it. If the electrician wiring a household is happy that the buried cables are under no danger and that the rcd will always provide protection then that is for that electrician to make the call, I'm only pointing out what is seen by many in the trade as good working practise, that's all.
 
Ken I do always do a quick test on 1st fix, but unfortunately even if you've done the tests and can prove it, the plasterer won't own up to it, it'll be 'oh the chippy was over here doing something' and then the chippy will say 'nah it wasn't me, it was the plumber.' It'll still be muggins who has to sort it out! Anyhow, I just like using oval I find it a lot easier than capping or just clipping - it doesn't bend out of shape and does exactly what you tell it to....
 

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