connections of cpc

[Engineer54]

Probably time to wrap this one up, the only other think I may add is that in areas such as warehouses there are various trunking systems installed, these can be vulnerable to various abuse by forklifts and the like, yes you could put them high but then when changing tenant this is not a consideration that the trunking system is not right for that environment , its just a trunking system to them and does the job. Invariable the trunking can be damaged (which I have seem many a time) and often just left. If you have that earth in place generally that will hold up if the trunking is damaged
Anyway, enough said

Regarding your reply in red to additional circuits, ....With all those unnecessary additional CPC's in a conduit you may well over fill that containment by the addition of one circuit, and you'll be daft enough to install yet another CPC to boot...lol!! That's why we have maximum fill capacities, for given sized containment, if you're going to overfill a given containment, then you're contravening BS7671 aren't you. In such circumstances, economics shouldn't come in to it!!


I don't live in a shell either, if you think for a moment that all the containment systems in all those factory plants i mentioned above were in pristine as new condition you would be very much mistaken. As stated by you, there was lots of accidental damage where forklifts had bashed into trunking and the like over the years, but deformed metal does not make any difference to it's continuity value. If a containment is damaged to the extent you're implying, then it's bad enough for that containment (and probably the conductors within) to be quickly and suitably rectified/repaired surely??

There is no excuse for any company for the neglect of any electrical installation. Using that as an excuse to include unnecessary CPC's in what is already a high integrity earthing system is a non starter as far as i'm concerned....

 

[sparks1234]

Regarding your reply in red to additional circuits, ....With all those unnecessary additional CPC's in a conduit you may well over fill that containment by the addition of one circuit, and you'll be daft enough to install yet another CPC to boot...lol!! That's why we have maximum fill capacities, for given sized containment, if you're going to overfill a given containment, then you're contravening BS7671 aren't you. In such circumstances, economics shouldn't come in to it!!


I don't live in a shell either, if you think for a moment that all the containment systems in all those factory plants i mentioned above were in pristine as new condition you would be very much mistaken. As stated by you, there was lots of accidental damage where forklifts had bashed into trunking and the like over the years, but deformed metal does not make any difference to it's continuity value. If a containment is damaged to the extent you're implying, then it's bad enough for that containment (and probably the conductors within) to be quickly and suitably rectified/repaired surely??

There is no excuse for any company for the neglect of any electrical installation. Using that as an excuse to include unnecessary CPC's in what is already a high integrity earthing system is a non starter as far as i'm concerned....

So, there we go, we all agree to disagree, shall we talk about earthing rods now, LOL

 

[Engineer54]

So, there we go, we all agree to disagree, shall we talk about earthing rods now, LOL

Away you go then, i'll leave it to you to kick it off!! ...lol!!

 

[sparks1234]

How bizzare
come across an install
relying on the trunking system for earth
its been damaged so no earth
oh if it only had a CPC

 

[Engineer54]

How bizzare
come across an install
relying on the trunking system for earth
its been damaged so no earth
oh if it only had a CPC

No earth, ..must have been cut in half then, not just damaged!! ....Which is indeed bizarre if none of the cables contained within that trunking weren't also affected/damaged!!

 

[sparks1234]

No earth, ..must have been cut in half then, not just damaged!! ....Which is indeed bizarre if none of the cables contained within that trunking weren't also affected/damaged!!

Lol
who said none of the cables were undamaged
all I'm saying is that's quite bizarre

 

[Engineer54]

So what are you saying that the cables in the trunking were repaired/replaced but the trunking was left as is?? Yep, ....that's bizarre alright!! But has nothing whatsoever to do with separate CPC's being warranted in a metallic containment, just incompetence on the part of whoever left the containment in such a condition!!

 

[sparks1234]

So what are you saying that the cables in the trunking were repaired/replaced but the trunking was left as is?? Yep, ....that's bizarre alright!! But has nothing whatsoever to do with separate CPC's being warranted in a metallic containment, just incompetence on the part of whoever left the containment in such a condition!!

Nope, that's not what I'm saying, some we're damaged, some were not, which I would say makes an even better case for separate CPC
as for your comment on incompetence, that's rediculous, things happen but then you live in a perfect engineers world. Lol

 

[Engineer54]

So they repaired the damaged cables and left the containment in half, get's better all the time!!
Nope, i live squarely in the real world, well enough to know that the containment would need to be completely in two, to make a statement that there wasn't any earth present past the damaged section....

 

[sparks1234]

Nobody said anything had been repairer Mr E54, All I am saying is a section of trunking has been damaged, some cables are damaged, some are not, some circuits have tripped, some have not, but the important factor is THERE IS NO EARTHING BECAUSE THE TRUNKING IS PULLED APART.
Got it?

 

[richy3333]

Old school stuff and its still found here and there, agree with eng 54 about the trunking being an earth but personally never liked it

Bugger, just did an install. I'm soooo unfashionable

 

[Mark6098]

Personally would agree there is no need to install separate cpc's but in the past 20 years of commercial/ industrial jobs I've been involved with never has the designer omitted cpc's on any distribution board schedule I've come across in an all metal containment system.

 

[Engineer54]

Personally would agree there is no need to install separate cpc's but in the past 20 years of commercial/ industrial jobs I've been involved with never has the designer omitted cpc's on any distribution board schedule I've come across in an all metal containment system.

Probably because the craftsmanship isn't there anymore, it's the ONLY reason i can think of, to fill a perfectly sound earthing system full of separate CPC's!!

 

[ipf]

On a job last month, leisure centre type of place, complete revamp just been done. Most of the lv installation was done in trunking and galv conduit and looked good......until you got close up. Above the suspended ceiling, lids missing all over the place, screws from joints and almost every mbb I came across was like Slack Alice. Maybe that's why they're insisting on separate cpc's. Once again, standards on the slide and, to some extent, overlooked. And, shouldn't be needed, I know but who the hell checks what's going on ? Never thought I'd be saying it but 'Oh for the old Clerk of Works'

 

[Engineer54]

On a job last month, leisure centre type of place, complete revamp just been done. Most of the lv installation was done in trunking and galv conduit and looked good......until you got close up. Above the suspended ceiling, lids missing all over the place, screws from joints and almost every mbb I came across was like Slack Alice. Maybe that's why they're insisting on separate cpc's. Once again, standards on the slide and, to some extent, overlooked. And, shouldn't be needed, I know but who the hell checks what's going on ? Never thought I'd be saying it but 'Oh for the old Clerk of Works'

So much for the ''Approved Contractor'' Status that's being banded about, as being the bee's knees of the industry!! lol!!

Electrical installation work above false ceilings should be signed off as being complete (along with any other services work eg ''ceiling closure certificate'') before any false ceiling are errected on any half decent project/contract. As you say, that would have been the Clerk of Works responsibility to head an inspection team with all the associated contractors/sub-contractors on the small to smaller medium projects/contracts....

Have the Clerk of Works disappeared altogether now then??