re chasing please help

[Greenworx]

Hi guys I'm getting suby doing a job for me as I've been really busy another job . I left at the job l went to see the job all chases are clipped but refusing to cap as he says according to 17th Edition if the lights and sockets are RCD protected you don't have use capping or put in conduit ,He's a very experience sparky please advise I thought it was good practice always.

 

[robsparky1975]

Good practise yes,beneficial as to stop a plasterers trowel damaging the cables,i have seen many a job where cables have been clipped direct then plastered over.

 

[robsparky1975]

incidentaly the rcd protection is for cables buried at a depth of less than 50mm from the surface amoung its other uses relating to whichever circuit it happens to be providing additional protection.

 

[SYKRAPS]

If you are paying his wages and you want it capped then tell him its your way or the high way...........I would always use capping btw but he is quite correct if external influences allow

 

[Greenworx]

Thank you for your quick response hes a lot more experience then me didn't want to say anything unless I was sure thank again

 

[DNS1]

Personally I've always been completely bewildered by the use of capping...

I've done a hell of a lot of plastering and I've NEVER managed to damage a cable with my trowel! Really not sure why some people insist on it! If you're talking about filling a chase, well the plasterer would have to be fairly incompetent to be jabbing his trowel in and ruining the cable sheath!

 

[SYKRAPS]

I use capping because that was the way I was taught many many moons ago so I guess it comes down to my teacher, but I agree its purpose is bizzare although I think it look neater before the plaster hides it lol

 

[Deleted member 9648]

Hi guys I'm getting suby doing a job for me as I've been really busy another job . I left at the job l went to see the job all chases are clipped but refusing to cap as he says according to 17th Edition if the lights and sockets are RCD protected you don't have use capping or put in conduit ,He's a very experience sparky please advise I thought it was good practice always.

You sure he's not a plumber?......his 'experience' clearly doesn't extend to a knowledge of the regulations.

 

[Amp David]

In a chase I usually don't bother capping but if onto new block or brick i do, as most of the time the wall don't get plastered for a whiles and theres sometimes other trades in the place crashing into everything, including new cables

 

[lauriehurman]

The heat dissipation, and hence the current carrying capacity, of the cable clipped to the wall and plastered over is GREATER than a cable in conduit.
In my very humble opinion capping won't stop a nail or a drill bit so doesn't fulfill 522.6.101 (iv) so what is it there for? It just hinders heat transfer from the cable.

I may be wrong.
Laurie

 

[GLENNSPARK]

whats this at #1 about refusing to nail channel over cables as `their RCD protected`?...lol....
since when has PVC/metal channel been classed as adequate mechanical protection from nails, screws and the like?...lol...

 

[dagrat]

The heat dissipation, and hence the current carrying capacity, of the cable clipped to the wall and plastered over is GREATER than a cable in conduit.
In my very humble opinion capping won't stop a nail or a drill bit so doesn't fulfill 522.6.101 (iv) so what is it there for? It just hinders heat transfer from the cable.

I may be wrong.
Laurie

Your quite right Lauriehurman, capping will not stop a nail or screw from puncturing a cable and is not intended to do so. Capping is purely a protection for the cables at the installation stage, to prevent any damage occurring prior to the completion of plastering.
Although there is a school of thought that suggests that it is easier to pull cables through capping if a later rewire is to be undertaken.
To be honest I don't often use capping anymore on smaller jobs, as I have never had a fault caused by the plasterers trowel to date. Maybe I've just been lucky:cool3:

 

[Amp David]

Laurie,

Have a quick read of post#9, pretty much says why capping is used.

 

[wade88]

Watch the stick i get for saying this.......

As a point of principle i always use oval conduit and screw it down with a repair washer top and bottom to hold it neatly in place.... ahh where is the little teachers pet smiley?!

But i do geniunely do that, yes it takes a little longer to finish the job, yes there is technically no need, yes its a pain in the ar$e, no it doesnt do me any favours, BUT and obviously its a big but because nothing should ever be going wrong with a new installed cable, but should that cable ever need changing/repairing/whatever, its a dream to pull it back out the chase and get a new one in it.

The next spark who comes along, will be singing your praises.... IMHO, it just makes for a more professional job...

TIN HAT

 

[Skyba]

Watch the stick i get for saying this.......

As a point of principle i always use oval conduit and screw it down with a repair washer top and bottom to hold it neatly in place.... ahh where is the little teachers pet smiley?!

But i do geniunely do that, yes it takes a little longer to finish the job, yes there is technically no need, yes its a pain in the ar$e, no it doesnt do me any favours, BUT and obviously its a big but because nothing should ever be going wrong with a new installed cable, but should that cable ever need changing/repairing/whatever, its a dream to pull it back out the chase and get a new one in it.

The next spark who comes along, will be singing your praises.... IMHO, it just makes for a more professional job...

TIN HAT

where do you work???

I'm going to come touting for work around your area in 15 years time could make myself a killing on speedy rewires lol

 

[PJK]

I have been an electrician for a long time and in NI I have never seen wiring plastered over, it is always in oval conduit, capping not used here. All builders I know would insist on oval conduit, and it makes re- wiring a lot easier. IMHO oval is a very professional job, and will continue to use it. All the housing associations here also insist on oval conduit before plastering.

 

[Amp David]

The use of oval is good, but not if you happen to have a few twins and maybe a 3 core and earth at the switch.

 

[i=p/u]

plastic pipe it in walls, and if use a correct drill bit for a wall you will feel you hitting the pipe... but hey ho long as works..

 

[PJK]

The use of oval is good, but not if you happen to have a few twins and maybe a 3 core and earth at the switch.

It can get tight, but I use three sizes of oval, 16mm, 22mm and 25mm and am able to get a couple of twins and 3 core and earth and a few singles down. Obviously it depends on the job etc., But there is no doubt that over in NI it seems to be oval conduit for all domestic and commercial work.

 

[wade88]

The use of oval is good, but not if you happen to have a few twins and maybe a 3 core and earth at the switch.

Then widen that chase up and get another length of oval in there. If its worth doing, its worth doing proper ..... dont shout at me.....

 

[Spudnik]

Must admit on rewires i use oval and on new builds capping.

Much easier to install cables and no need to try and clip them individually to thermalite blocks or weak joints.

 

[GLENNSPARK]

use some stench pipe (110mm)....but dont forget max. depth of chases will you....
what i mean is you may find the stench pipe bulges out into the living room....if this happens just paint same colour, paper over (as best you can)....or buy some tall furniture to hide it....

 

[DNS1]

Why not go the whole hog and use 160mm?!

Is there a maximum size of "conduit" before the cable is considered to be "in free air"?

 

[DNS1]

It can get tight, but I use three sizes of oval, 16mm, 22mm and 25mm and am able to get a couple of twins and 3 core and earth and a few singles down.

Do you not end up having to apply an inconvenient de-rate to the cables with that much crammed in a conduit?

Come to think of it, I don't recall seeing anything in the regs about the size of the conduit used... Presumably you have to apply the same de-rate whether you're running a couple of 2.5mm in a 16mm oval, or Glennsparks 110mm soil pipe!

 

[SirKit Breaker]

Agree with all the other posts, but although capping is there to protect the cables from plasterers and the like, its original purpose was to stop the lime in the plaster degrading the cables. lime is no longer used in plaster, so form your own opinions of what you need to do.

Cheers............Howard

 

[Guest55]

in 20 years of sparking i've never known a plasterer to cut through a cable during bonding coat.
thats all i'm gonna say lol.

 

[DNS1]

in 20 years of sparking i've never known a plasterer to cut through a cable during bonding coat.
thats all i'm gonna say lol.

At least they've never admitted to it!

 

[applemac]

i like oval for switch drops , it payed off for me once a plumber or similar type chappy put a screw right in the bleedin wire, managed to pull old bit out followed by a nice new length job done in 15 mins