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Topic Title: Galvanised Steel Channel
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Created On: 22 September 2016 12:23 pm
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 22 September 2016 12:23 pm
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Mrlecy

Posts: 29
Joined: 01 September 2016

Hi all,

Just wanted your advice on if its appropriate to use Galvanised Steel Channel 25mm x 2m for protecting electrical wiring routes mostly for drop down cables to the light switches, from drilling or nailing into them. Not sure if its

I will be plastering over.


Really appreciate any advice.

Thanks all.

Edited: 22 September 2016 at 01:27 pm by Mrlecy
 22 September 2016 01:07 pm
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di515223

Posts: 337
Joined: 08 July 2010

Depends on the channel- some I have seen is so thin it wouldn't protect against a drawing pin, never mind a nail!,especially if you only have a couple of mm of plaster over the top of it.
there are more robust channels available, so I would have a look around to seee what works best for you. (it may be that other optuions are better in you circumstances,)

Dave
 22 September 2016 01:35 pm
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mapj1

Posts: 12039
Joined: 22 July 2004

Well, regs wise, if the power or lights are on RCD, you could equally well have plastic capping or even nothing at all between the wire and plaster.
However, if you want to omit the RCD, you need a cable with earthed jacket, or a proper earthed metal conduit. The thin capping is not normally made to be easily earthed.
From a regs point of view, the thin sheet metal capping is in a bit of a no-man's land, as where you might use, it you don't need it, and where you might need something a bit stronger, its not really strong enough.
Good idea perhaps if you may want to re-thread that switch drop...

-------------------------
regards Mike
 22 September 2016 01:36 pm
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leckie

Posts: 4705
Joined: 21 November 2008

Standard steel channel/capping is not there to protect against penetration, just to protect cable while the construction works are taking place. Plastering, etc.
 22 September 2016 01:54 pm
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spinlondon

Posts: 5494
Joined: 10 December 2004

Even earthed capping is not acceptable, though some believe it is.
 22 September 2016 02:02 pm
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Mrlecy

Posts: 29
Joined: 01 September 2016

Thanks for the responses - All the cables are on RCD's I was just thinking on the lines of protecting the cables from nailing or even drilling. I once had an Arial fitter who drilled through and damaged the cables and the RCD kept tripping.
So the RCD's are there just wanted to add in the extra layer of protection to the cables.


So do I still need to earth the metal channelling if I have RCD's? If so what is the best way to earth it, take an earth from the light switch?
 22 September 2016 02:30 pm
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OMS

Posts: 22864
Joined: 23 March 2004

Sounds totally unnecessary to me if the cables are in zones (and you have RCD protection anyway)

However, playing along with this - if you earth the channel, how do you inspect the joint/termination - unless you plan to weld something in place that is (ie make it a permanent non inspected termination)

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 22 September 2016 02:39 pm
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Mrlecy

Posts: 29
Joined: 01 September 2016

I am only covering the bare cables that don't have any joints or terminations along the drop down cable in the channel.
 22 September 2016 02:42 pm
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OMS

Posts: 22864
Joined: 23 March 2004

I think you missed my point - it's the earth connection to the channel I was discussing

OMS

-------------------------
Let the wind blow you, across a big floor.
 22 September 2016 02:46 pm
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Mrlecy

Posts: 29
Joined: 01 September 2016

Yes, sorry I did miss your point. I was thinking to take the earth from the switch knockout box and earth bond the earth wire outside of the channel.

Appreciate your support.
 22 September 2016 03:06 pm
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spinlondon

Posts: 5494
Joined: 10 December 2004

Damn, what have I started?
Do not earth the capping.
It is unnecessary and not an acceptable method for providing additional protection.
If you are worried about someone drilling or nailing into cables, provide suitable mechanical protection.
Perhaps 20mm conduit or 3mm metal plate.
 23 September 2016 05:21 pm
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Fm

Posts: 2032
Joined: 24 August 2011

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