Should I use 1mm or 1.5mm earth in domestic lighthing?

[midiman]

Hi,

I need to earth a replacement faceplate to a steel back box in the wall.

Should I use a 1mm, or 1.5mm sleeved cable for the job?

Thanks

 

[telectrix]

what we need is as was developed by star trek .dr.mccoy .laser probe cuts through skin but not tissue ( insulation) and conductor ( bones )

 

[PEG]

Vortigen is correct,and then you just have to step back,and let each to their own.

I have,and would never,run a knife around the sheath of a SWA,because the tiny cut to the plated steel armouring,is where the corrosion starts...simple as that.

I would not unduly apply scorn,to a man using a knife to do the same task,it's just that he's wrong...and i'm not

 

[The Ghost]

Just as a matter of interest @PEG how do you strip the outer sheath of SWA without the aid of a sharp implement?

 

[Midwest]

Might change your mind if you were taught correctly in the first place Middy.

I think I was taught rightly or wrongly, of both ways. Never seemed an issue to me not to use a knife.

 

[NDG Elecs]

I can categorically state that using the CPC as a rip cord does decrease the CSA. Recently I had a small ring with L-L and N-N each measuring 0.10 ohms. Due to my poor de-sheathing technique the CPC when tested was 0.169 ohms. The 0.002 ohm shortfall posed a very real fire risk in my view so I immediately pulled the walls apart and rewired it all. It's a shame really as the plasterer and decorator had only been in the week before..

 

[PEG]

Just as a matter of interest @PEG how do you strip the outer sheath of SWA without the aid of a sharp implement?

I have always used either a Klauke or Thomas Betts scoring tool,which whips round the periphery of a circular sheath,with an adjustable depth,swivelling cutter. A couple of spins,and then pull off the end,results in the sheath coming off like an onion skin.

Same tool will do many sizes,and flexible cables,spring loaded design,blade can be replaced,although i never have,just dressed up with a DMT hone.

If i was demonstrating the benefit of such a tool to students,i would get them all to strip 6" of the sheath,on a 12" piece of SWA,using standard knifes,etc.

I would then strip 3" off the other end,using my favoured weapon. Both ends can then be coated in a weak acid solution,to speed up simulated corrosion,and left for a week or so.

When the remaining sheath is removed,it is obvious,which process is the most beneficial.

....Or,i could just accept the frequent advice,regarding getting either "out more" or "a life"

 

[telectrix]

with SWA, i use the CK armourslice. first to score the armour prior to breaking off, then approx. 1" back to cut the outer sheath. all done in one operation.