y oh y

[cliffed]

taking over a job from a old sparkie,really nice jobby,trunkin & conduit,biggest warehouse.Wots your feelin on this,cos just had a mighty row wiv him.3 lighting circuits cabled in 2.5mm,quite a long run,switching low bay lighting in 3 rows,via 2 2way switches & 1 intermeddiate.At the switch position there shud of been 3 earths to match the 3 circuits,but no,the earths stop at the lighting points,& 1 earth is then taken from a circuit 2 the switch,this happens at all switch positions,so wot do u think.Major problem now is gettin the relevant earths 2 each switch,cos 25mm conduit full 2 the brim,my gaffer thinks it may b ok,but he wud.

 

[Engineer54]

Why would you change to PVC?

Because you would be hard pushed to find one of the new breed of so-called electricians that can work with metal containment systems!! All they seem to know is T&E and SWA and at best PVC conduit and trunking...lol!!!

 

[Andy78]

I got taught by some old school guys who will now be in their 70s. One of my first jobs was a fortnight of making up steel conduit sets, and have many years experience since. I got taught the proper way to install tray, trunking and conduit. I was taught to make bends and angles for tray and trunking even though we had pre-made bends to hand, just so I knew how.
One thing I was never taught though was how to use metal containment as a proper CPC. I was always told "Yes you can, but it's a right load of fannying about with earth straps on every joint so it's easier to pull an earth in" Am I missing out on a big part of containment knowledge ?

 

[oldtimer]

I got taught by some old school guys who will now be in their 70s. One of my first jobs was a fortnight of making up steel conduit sets, and have many years experience since. I got taught the proper way to install tray, trunking and conduit. I was taught to make bends and angles for tray and trunking even though we had pre-made bends to hand, just so I knew how.
One thing I was never taught though was how to use metal containment as a proper CPC. I was always told "Yes you can, but it's a right load of fannying about with earth straps on every joint so it's easier to pull an earth in" Am I missing out on a big part of containment knowledge ?

I would point out that befor the 15th edition came out earth straps were never even mentioned and it was box standard to run a 2x2 or 3x3 trunking around a building with conduit drops spurring off in fact if you go to some jobs when the 15th came out managers were telling their guys that if they ran tray they had to make up short 150mm 4mm earth cable straps at each joint and when I questioned this I was told this is the regulations and I said but the joint peice bolting the 2 bits together makes it Electrically and Mechanically sound

 

[Engineer54]

I got taught by some old school guys who will now be in their 70s. One of my first jobs was a fortnight of making up steel conduit sets, and have many years experience since. I got taught the proper way to install tray, trunking and conduit. I was taught to make bends and angles for tray and trunking even though we had pre-made bends to hand, just so I knew how.
One thing I was never taught though was how to use metal containment as a proper CPC. I was always told "Yes you can, but it's a right load of fannying about with earth straps on every joint so it's easier to pull an earth in" Am I missing out on a big part of containment knowledge ?

They were using metal containment long before the now common use of copper earth straps, and it's not been that long in real terms, that CPC's were even insulated... But the metal containment was still the source for your CPC!!!
To be totally honest, i can't see any ''fannying'' around is needed fitting those copper earth straps to trunking and the like, after all, they use the same holes your going to bolt through anyway!!!!

 

[Andy78]

No worries. Like I said, I have never used containment as a CPC or been shown how, so didn't know if there were any special conditions to do so. So as long as each joint is mechanically sound its a good un ? Common sense would tell me to file away paint and powder coating on DBs, enclosures, and accessories where they join to containment. Then just test the CPC as normal ?