Steel or PVC?

[Tinyotall]

Need to first fix a porch, does it matter which capping I use? PVC or Steel?

 

[Sintra]

Really depends whether or not you want to give the circuit additional protection by 30mA RCD or not.

 

[Tinyotall]

The circuit has to have RCD by the time i'm finished!

 

[sparks1234]

Really depends whether or not you want to give the circuit additional protection by 30mA RCD or not.

Makes no difference if the capping is steel or plastic, it still needs protection by RCD

 

[johnboy6083]

i reckon sintra miosread it, he prob thought conduit!

 

[yellowvanman]

Steel or pvc - depends on how much protection you need to give the cables from damage. Probably domestic porch PVC would be adequate, if in a machine shop then probably steel would be best!

 

[johnboy6083]

capping only protects the cable from the plasterers trowel. that is it. it offers no other protection, as its designed to be buried under plaster or render. if you were to try and drill through it or hammer a nail through it, you wouldnt even know you had gone through it, until the cable goes bang.

 

[Sintra]

i reckon sintra miosread it, he prob thought conduit!

Yes unfortunately the eyesight isn't quite what it used to be.

 

[johnboy6083]

my speeling is the smae!

 

[madmac]

capping only protects the cable from the plasterers trowel. that is it. it offers no other protection, as its designed to be buried under plaster or render. if you were to try and drill through it or hammer a nail through it, you wouldnt even know you had gone through it, until the cable goes bang.

johnboy6083: You are right that a drill or nail would pass through the capping very easily and it is also the case that an ordinary person could drive a tac with their thumb through capping given enough force! but capping is not there to provide mechanical protection, it is there to provide EEBADS. So, if their is a 30mA, rcd fitted to the circuit then according to BS7671:2008, and as long as the cable is ran in a "safe zone", there is no need for capping but if the rcd fails or is changed to a mcb at a later date, then IMO, I still fit metallic capping and earth it to the nearest socket to give old fashioned EEBADS. Also, IMO. pvc capping is an utter waste of time and money and provides little or no mechanical protection and because it can't be earthed provides no means for ADS what so ever. Not having a go at you mate but you raised a very good point that a lot of sparks are getting lost on.

 

[SPARTYKUS]

Madmac are you having a laugh, capping is to stop to plasterers trowel! Thats all. If you want to fit a flying lead to every off cut of capping so be it!

 

[jaresquire]

Just curious, Madmac, how do you earth the capping (never done it or seen it done myself)

 

[madmac]

Madmac are you having a laugh, capping is to stop to plasterers trowel! Thats all. If you want to fit a flying lead to every off cut of capping so be it!

Who the **** told you that wives tale? Are you serious? Are you having a laugh? Think about what you just said and read up on EEBADS. In fact, don't bother, I've had enough of trying to put across good electrical practise, so if you think that's all capping is for........then fire away big man!

 

[madmac]

Just curious, Madmac, how do you earth the capping (never done it or seen it done myself)

jaresquire: All you do is take a flying lead of 2.5mm earth cable from one of the fixing points of the capping to the socket outlet/light fitting/light switch earthing terminal and in a matter of seconds you have provided EEBADS to the capping and protected the buried cable, simple really but lost on some guys who seem to think this is a major project of some description but thanks for taking an interest anyway mate.

 

[SPARTYKUS]

Good luck with that capping madmac!

Alway been taught that as per other posts. Possibly why plastic version is made too.

Be good if you answered the others' questions just to explain how you go about it.

Hope youre not on the wind up, if not i return your tankard and bid you good day

 

[jaresquire]

Cheers. Wouldn't work with my capping due to all the gaps!
It's usually covered in blood as well.

 

[Tinyotall]

More confused now then when I started! some help!!!

 

[madmac]

Ok boys, it really isnae that hard, think about it for a minute.
You have an unprotected cable( assuming the rcd is ****ed or non-existent), and the ordinary person puts a tac or nail or some other foreign body through the cable!!! It hits the line conductor( live conductor in the good old days), and the ordinary person gets plated!!!!!!!!!!!
OR, the cable is covered with metallic capping which is also earthed by way of a flying lead.......the same situation causes line conductor to initiate a short to earth, which in turn causes an over-load of the the protective device and trips/breaks/fuses the circuit into an isolated/open circuit!!! It really is that simple, or people are seriously misinterpreting basic understanding of electrical practises!!!

 

[Wully]

Agree with madmac we do the same, metal capping over cables gets earth even with the circuit on a RCD. Must be a Scottish thing.

However I changed my mind about the whole thing a few weeks ago, now using pvc. At the end of the day its only for trowel protection.

 

[SMB]

I met someone once who bonded a metal widow frame........