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Diver233

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we have just had over 200sqm of suspended ceiling installed throughout our new offices it’s all metal grid.
Does anyone bond to that metalwork ?.
Interested in everyone’s thoughts.
 
Tricky one that. Having received 120v shock between the metal grid and the earth on the klix fittings it is something to consider carefully. The building in question is steel girder and metal roofs with block work and concrete floors. There are three buildings on site and two had this problem. We have in one set jack chain and fluors off of metal girders/roof trusses all metal. In the other Cat II 600 x 600 fluors. One of the failures in the original install was the fly lead from SWA gland and earth bus bar was not installed. It took some thinking about to obviate the problem. So I would say careful consideration and testing before deciding one way or the other.
 
I`d say yes , have done it in the past and have seen it on other large commercial installs. Extraneous-Conductive-Part – A conductive part liable to introduce a potential, generally Earth potential, and not forming part of the electrical installation.

 
I would put my vote in for bonding it.
It’s metal, it’s extraneous, it’s conducive.
Simple?
 
Not in most cases, but giving it a test to prove it would be a good idea.
Personally I’ve never needed to bond one but if you did do you have to make up flying leads? I ask because the way most of them are constructed surely cannot be electrically sound? The slots were never designed to pass current of any sort or provide good continuity, so surely all of the main rails would require a fly lead to each other and all of the cross rails would also require fly leads into the main rails, should it be determined that bonding was necessary
 
You don’t bond grid ceilings, unless they are extraneous.
So if you have a ceiling which extends outside the building, then yes you would bond that.
You can earth them as if they were an exposed conductive-part, but they’re not really part of the wiring system.

To my mind, it’s better to ensure the fittings have been correctly terminated.
 
No need to bond,not extraneous,years ago it was always specificed to bond,but now us sparkies are all in the know,not told by some tech guy speaking to you like a classroom idiot...Clerk of the works type.
 
no is the answer .what type of fitting are installed ,are they luva type then if so they will be earthed any way ,but if they are led then they will not have a earth.
just fitted 26 600 x 600 LED panels in ceiling grid. all panels were earthed. the distorted grid required hammers and pry bars to get the buggers in though. that's a different story.
 
Not in most cases, but giving it a test to prove it would be a good idea.
Personally I’ve never needed to bond one but if you did do you have to make up flying leads? I ask because the way most of them are constructed surely cannot be electrically sound? The slots were never designed to pass current of any sort or provide good continuity, so surely all of the main rails would require a fly lead to each other and all of the cross rails would also require fly leads into the main rails, should it be determined that bonding was necessary

This for me is where the problems begin.

Where do you bond, how many times and at how many locations do you test?

I get it's a belt and braces approach but what if you do bond, and someone gets a crack (somewhere where there is poor continuity between grid rails) regardless.

How do you go about explaining your rationale to the HSE?

I'd argue that while the grid may be connected, directly or indirectly, to an extraneous conductive part (which should be bonded) it does not form an extraneous conductive part in and of itself. It is not part of the electrical installation so cannot be an exposed conductive part. Therefore I see no need to bond.

I think.
 
Test it and you know. Don’t know why bonding vs earthing causes so many issues

And if the grid is hung from extraneous structural steel you'll get an low resistance reading, yet the steel will be bonded (always worth checking) so no need to bond the grid.

With all the service pipe work, cable tray, steel etc.. above a suspended ceiling, which may be extraneous and bonded, I'm worried you'd be leading yourself a merry dance.

Only my thoughts tough.
 

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