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Topic Title: Safe zone at the wall ceiling junction
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Created On: 24 February 2010 05:20 PM
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 24 February 2010 05:20 PM
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OJ

Posts: 22
Joined: 17 October 2005

If a switch cable runs vertically up a wall from the switch and enters the ceiling, is that cable considered unprotected from the point at which it enters the ceiling to a point where it is above 50mm from the bottom of the ceiling joist? Is it assumed that the safe zone formed upwards from the switch extends a short distance into the ceiling or should we be protecting this short section of cable?
 24 February 2010 05:24 PM
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MrAmps

Posts: 386
Joined: 11 December 2006

I would say that if the cable is <50mm from any surface then it requires protection?
 24 February 2010 05:33 PM
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daveparry1

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Joined: 04 July 2007

Are we now saying that we need to put in 2 inches of earthed steel conduit above the ceiling? don't be daft!
Dave.
 24 February 2010 05:55 PM
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olderthandirt

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I believe that the cable enters a safe zone some 150mm from the ceiling on a vertical run.
 24 February 2010 11:01 PM
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RRichard

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Originally posted by: olderthandirt

I believe that the cable enters a safe zone some 150mm from the ceiling on a vertical run.


I second that.
 24 February 2010 11:11 PM
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daveparry1

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OJ is questioning whether or not that safe zone extends above the ceiling!
 24 February 2010 11:25 PM
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Dale76uk

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Joined: 04 February 2010

why not use mechanical protection from the switch/socket which enters 50mm above the ceiling??? I've always done this.
 24 February 2010 11:37 PM
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spinlondon

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The requirement is for the cable to be protected from nails and screws, where it passes through a joist.
I don't think it is considered likely that someone will put nails and screws in between joists.
 24 February 2010 11:40 PM
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Martynduerden

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Following an assessment of the likely damage to occur to the said 50mm above the ceiling...

Come on guys is it likely that a picture is going to go within the floor joist.

As for protection I am yet to see any installed so as to negate the use of rcd's capping ..yes but its not mechanical protection is it?

-------------------------
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Martyn.

Only a mediocre person is always at their best



www.electrical contractors uk.com
 25 February 2010 08:45 AM
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daveparry1

Posts: 6377
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why not use mechanical protection from the switch/socket which enters 50mm above the ceiling??? I've always done this.
--------------------------------------

And how do you do that Dale? 50mm of earthed steel conduit? ridiculous. Nothing else will provide mechanical protection, steel capping for instance isn't regarded as mechanical protection.
 25 February 2010 06:00 PM
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rikhill

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Originally posted by: OJ

If a switch cable runs vertically up a wall from the switch and enters the ceiling, is that cable considered unprotected from the point at which it enters the ceiling to a point where it is above 50mm from the bottom of the ceiling joist? Is it assumed that the safe zone formed upwards from the switch extends a short distance into the ceiling or should we be protecting this short section of cable?


No it is not : read 522.6.5 more carefully.

The 50mm stipulation only applies when passing through a joist.

Apart from that you should 'run in such a position that it is not liable to be damaged by contact with the .. ceiling or their fixings' directly above a wall at any height would comply.
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