Main bonding conductors connected to trunking.

[Chr!s]

And there was me thinking that metal trunking/tray containment systems always use at least 2 copper links between bolted sections!!!!

Not on the new stuff E54, unless you don't trust what the manufactures say that is.

 

[Deleted member 26818]

And there was me thinking that metal trunking/tray containment systems always use at least 2 copper bonding links between bolted sections!!!!

No just the one.

 

[Engineer54]

Not on the new stuff E54, unless you don't trust what the manufactures say that is.

No just the one.

Always used a minimum of two, (one on each side of the butted sections) that was the norm, and as far as i'm concerned, still the norm on metal containment systems no matter what the manufacturers say. But then I suppose these days, even retaining one copper link is something of a miracle!! lol!!

Do they still call for 2 copper bonding links placed at diagonal corners across non metallic expansion joints on A/C ductwork, or has that gone by the board as well??

 

[kingeri]

Is that a bit like bonding across compression fittings on copper pipework?

 

[Deleted member 26818]

Always used a minimum of two, (one on each side of the butted sections) that was the norm, and as far as i'm concerned, still the norm on metal containment systems no matter what the manufacturers say. But then I suppose these days, even retaining one copper link is something of a miracle!! lol!!

Do they still call for 2 copper bonding links placed at diagonal corners across non metallic expansion joints on A/C ductwork, or has that gone by the board as well??

Whilst the straight sections of trunking could have a link either side, the bends and sets only have a knock out hole (usually with an earth adjacent), on the one side.
If you wanted to add another link, you would have to drill a hole, which would suggest that only the one link is deemed as being necessary.

No there doesn't appear to be a requirement for bonding across expansion joints in A/C ductwork.

 

[Engineer54]

Whilst the straight sections of trunking could have a link either side, the bends and sets only have a knock out hole (usually with an earth adjacent), on the one side.
If you wanted to add another link, you would have to drill a hole, which would suggest that only the one link is deemed as being necessary.

No there doesn't appear to be a requirement for bonding across expansion joints in A/C ductwork.

That i would have thought, would be standard practice, when fabrication of sections are required on metal containment systems??

Why did i know that was going to be the feed back, on the A/C ductwork... lol!!

 

[D Skelton]

Always used a minimum of two, (one on each side of the butted sections) that was the norm, and as far as i'm concerned, still the norm on metal containment systems no matter what the manufacturers say. But then I suppose these days, even retaining one copper link is something of a miracle!! lol!!

Do they still call for 2 copper bonding links placed at diagonal corners across non metallic expansion joints on A/C ductwork, or has that gone by the board as well??

I suppose this all comes down to how you were taught. I only found out recently that you need not link between joints in metallic containment systems or A/C ductwork, but I always have and will continue to do so! 2 links in my mind would be a little overkill but again, it comes back to what you were taught and also what you're comfortable with.

 

[Guest55]

In a commercial/Industrial scenario you will find many a connection through out the length of the Main Bonding

Yes but its designed like that to begin with , not retro bodged at a later date from what was a superior arrangement.

Well, who ever is carrying out work on any installation needs to be competent to do so, you cant design a fortress.

Well a continuous conductor from a to b is fairly bombproof.

...................

 

[Chr!s]

...................

We don't know if it's a bodge, it well be fine, you can't code it just because you don't like the idea.

The continuous conductor with to connections one at either end.

 

[Guest55]

We don't know if it's a bodge, it well be fine, you can't code it just because you don't like the idea.

i'm sure i'll find something to code if i looked hard enough.
the contractor seems suspect if these are his recommended "improvements"

The continuous conductor with to connections one at either end.

Is fundamentally better than one with additional connections in the middle , that already existed in the first place

You can throw in as many technical counter-points as you like but....
a bad idea , that just happens to comply with bs7671 , probably by sheer good luck , is still a bad idea.
;-)
you must of course think it a great idea following your rigorous defence of this "improvement" ?
:-D

 

[shoddyboby]

:61:hi all am new jus posting to start up my account

 

[MarkieSparkie]

Yes E54, that's the way we were trained back in the day mate, when the standard of British workmanship was valued, these days it seems that monkey spit and high hopes are good enough; well not for me... do it once, do it right!

 

[Chr!s]

You can throw in as many technical counter-points as you like but....
a bad idea , that just happens to comply with bs7671 , probably by sheer good luck , is still a bad idea.
;-)
you must of course think it a great idea following your rigorous defence of this "improvement" ?
:-D

We have been using Trunking as a Protective conductor for years, installed correctly its a good system the same as any other, Trunking as a protective Conductor a bad idea? No i don't think so.

Improvement? Well it maybe, why has he done it? Maybe he knows what he is doing and there is no "sheer good luck" to do with it, just a good competent electrician.

AS for further codes, here are your first two.

youre right.
main bonds should be continuous and unbroken en route to the services.
only cpc's can use metal containment as a carrier.
i'd give it only a code 3 defect on an inspection to be fair though.

Incorrect

well it is connected to the MET if the trunking forms part of the main bonding ?

Does the trunking earth fixing bolts have "safety electrical connection" tags that you find on pipe clamps ?
if not you can code it on that alone ;-)

Incorrect


So two codes you have given are incorrect, third time lucky maybe?

As i said you need to be competent.

 

[Guest55]

We have been using Trunking as a Protective conductor for years, installed correctly its a good system the same as any other, Trunking as a protective Conductor a bad idea? No i don't think so.

i never said using trunking for earthing was a bad idea but changing it from a continuous , dedicated conductor that already existed is a good idea ?



Improvement? Well it maybe, why has he done it? Maybe he knows what he is doing and there is no "sheer good luck" to do with it, just a good competent electrician.

we'll never know without looking at the job will we ?



AS for further codes, here are your first two.



Incorrect



Incorrect


So two codes you have given are incorrect, third time lucky maybe?

ooh thats so cruel , good job i'm thick skinned.
i conceed my mistakes on those 2 points , touche.




As i said you need to be competent.

.............

 

[Chr!s]

I do apologise Biff, no cruel intention, a poor post, must do better