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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.
 
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I was fairly sure it doesn’t need it, but just thought I’d ask.
Thank you
 
T

The Ghost

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.

 

James

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I would put my vote in for bonding it.
It’s metal, it’s extraneous, it’s conducive.
Simple?
 

MFS Electrical

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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
 
D

Deleted member 26818

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.
 

DPG

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How on earth (see what I did there?!) would you bond the entirety of a suspended ceiling grid and ensure that every piece of metal was satisfactorily bonded?
 
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.
 

telectrix

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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.
 

GBDamo

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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.
 

GBDamo

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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.
 

edexlab

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Talking to a new bloke today that said

"This might be a stupid question "

I said straightaway " No such thing as a stupid question "

He immediately says
" Do you like sausages?"
.......................
"Ok I'm wrong there is such a thing as a stupid question!"
 
D

Deleted member 26818

Talking to a new bloke today that said

"This might be a stupid question "

I said straightaway " No such thing as a stupid question "

He immediately says
" Do you like sausages?"
.......................
"Ok I'm wrong there is such a thing as a stupid question!"
Why is it stupid?
 

edexlab

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Arms
Sorry my bad, this was at work,
I assumed people would get that by saying "New bloke"
At the time I was talking him through some of the machines we build, so in this situation it was....
Had I been in the chippy......
 
... fitted 26 600 x 600 LED panels in ceiling grid. ....panels were earthed....required hammers and pry bars....
Enough paint was scratched off to ensure earth continuity to the grid in some places.
To reduce capacitve pickup from random cables lying out of view "all over place".
 
There is a section on ceiling grids in guidance notes 8 and it says
“The conductive parts of a suspended ceiling will not introduce a potential that does not already exist in the space in which the ceiling is installed. In normal circumstances, there is therefore no need to arrange for the conductive parts of the ceiling to be equipotentially bonded, which would be unnecessary as well as difficult and costly to achieve.” It later goes on to say that as long as all electrical equipment and cabling complies to BS7671 there is no need to bond.
 

GBDamo

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Well, after laughing at this question initially, I was looking through a tendering document today and lo and behold one of the requirements was to bond all pipework, structural steel and suspended ceiling grids.

This was a council job, so you'd think there was someone who knows what's what.
 

TJ Anderson

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Realistically a pain in the arse to confirm if extraneous if existing and if you have lots of fittings in it which are themselves earthed as they are exposed conductive parts so grid is likely already at earth potential from this.

If it's new you can test it with a IR tester at 500v. If >22kohms between bare grid and MET the you can consider it not extraneous.

If unproved, I'd shy away from bonding it as you then really should be adding supplementary bonding between sections to ensure the bonded potential across the whole grid, otherwise you are relying on bent steel joins maintaining your continuity which you are officially stating is bonded.

As it is very unlikely to be truly extraneous and unless you test and prove it, a better solution is to utilise a cpc from the largest circuit that supplies fittings in the grid and link that cpc onto the grid via a fly lead equal to cpc size and a ring crimp. This will ensure grid is at earth potential and will ADS under fault. The advantage of this is you are not vouching for the earth potential of the whole grid as it is not a requirement, whereas with bonding you will be albeit for a different reason.

To summarise, Bonding and cpc will both get grid at earth potential but if it is not truely extraneous then it should only be put at that potential by a cpc.......In my opinion of course!!
 

telectrix

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Well, after laughing at this question initially, I was looking through a tendering document today and lo and behold one of the requirements was to bond all pipework, structural steel and suspended ceiling grids.

This was a council job, so you'd think there was someone who knows what's what.
a contradiction in terms there, buddy.
 

littlespark

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Be a nice little earner; on an hourly rate, making up little earth links and self tapping screws across every joint in a suspended ceiling grid.
Can we make this a new regulation?
 

PEG

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Be a nice little earner; on an hourly rate, making up little earth links and self tapping screws across every joint in a suspended ceiling grid.
Can we make this a new regulation?
...and would you test to confirm each and every one?
....or just hope the testing at each and every point,picked up a problem...:)
 

DPG

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I still can't believe anyone is going to provide every piece of a suspended ceiling grid with adequate earth bonding.
 
T

Toneyz

It still is in a lot of spec's we have and most of them seem to be generic except for a few pages. Is there anyone on here that used to have to do it? I remember when I was an apprentice or just after around the 15th (brown book) bonding all the pipes under a combi boiler (that all connected onto a metal bar) makes you wonder what the people writing the regs was thinking.
 

Baddegg

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Talking to a new bloke today that said

"This might be a stupid question "

I said straightaway " No such thing as a stupid question "

He immediately says
" Do you like sausages?"
.......................
"Ok I'm wrong there is such a thing as a stupid question!"
Do you?
 

Dave OCD

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the tails look OK.the rest is beyond a monkey's abortion. don't use this for your niceic assessment.
It still is in a lot of spec's we have and most of them seem to be generic except for a few pages. Is there anyone on here that used to have to do it? I remember when I was an apprentice or just after around the 15th (brown book) bonding all the pipes under a combi boiler (that all connected onto a metal bar) makes you wonder what the people writing the regs was thinking.
I've done that many times Anthony, continuous 10mm all the way across with insulation stripped at each earthing strap and all with the same 'loop' between.
 
T

Toneyz

I have only seen it cross-bonded with 4mm earth to each main T bar.
 

Dave OCD

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I always used 10mm, sometimes just continuing the main gas bond unbroken across all the pipes.
 

Megawatt

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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.
When in doubt bond it
 

Pete999

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When in doubt bond it
NOT taking the P--s Megawatt, grateful if you could set my mind at rest , what constitutes a Master Electrician in the US or Canada? when I was working short term in Canada, I got told by the sales person in "Home Depot" you can't have such and such unless you are a Master Electrician, so I asking out of genuine concern, no intention of deriding the term in any way just curious.
 
B

Bobster

NOT taking the P--s Megawatt, grateful if you could set my mind at rest , what constitutes a Master Electrician in the US or Canada? when I was working short term in Canada, I got told by the sales person in "Home Depot" you can't have such and such unless you are a Master Electrician, so I asking out of genuine concern, no intention of deriding the term in any way just curious.
A master electrician is someone who has moved past the apprentice and journeyman stages of their career. ... A journeyman electrician will not have the same experience or licenses as a master electrician. Journeymen may be able to work independently, but do not have complete autonomy.

Basically, just experience, and a different license.

Journeyman would be in my eyes, when I finished my apprenticeship, I was considered an improver for a year after. Qualified, but still needed to pass designs etc through someone more senior.
 

Pete999

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A master electrician is someone who has moved past the apprentice and journeyman stages of their career. ... A journeyman electrician will not have the same experience or licenses as a master electrician. Journeymen may be able to work independently, but do not have complete autonomy.

Basically, just experience, and a different license.

Journeyman would be in my eyes, when I finished my apprenticeship, I was considered an improver for a year after. Qualified, but still needed to pass designs etc through someone more senior.
Thanks Rob
 
T

Toneyz

Sounds a good idea, Pete. Did you have any experience of it when you were over there?
 
D

Deleted member 26818

It’s also a term used in the UK military.
An Electrician who is also a Master Sergeant or Warrant Officer.
 
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