This might be a stupid question

[Jon Bateson]

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

 

[GBDamo]

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]

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]

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!"

 

[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]

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......

 

[static zap]

... 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".

 

[Gavin Price]

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.

 

[DPG]

At least GN8 talks sense!

 

[GBDamo]

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]

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]

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]

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]

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...

 

[dmxtothemax]

Whilst you may not "have to" if you are concerned ?
Then there is nothing stopping you from doing so !