trunking earth links

[iamelectric]

are copper earth links on trunking compulsory , or in the regs book

 

[spark 68]

I think the last thread on this subject the consensus was split roughly 50:50, some sparks said they were, and some said not.

However if the site you are working on has specced them into the job then that is what you will fit.

 

[iamelectric]

so good practice but not compulsory

 

[spark 68]

I cannot remember exactly the thread in question, but I think it depended on a) the size of the trunking, and/or b) if the trunking is also used as a cpc.

Just to add, all of the sites I worked on either the solid links or short cable links were specced in the job.

 

[johnboy6083]

Not compulsory, but often specced. What is compulsory is to have earth continuity from one end of the trunking to the other, that is able to take the fault current.
Most trunking come with solid joiners anyway, so why would a copper link help?

 

[Minime]

No not needed

 

[Engineer54]

Anything for an easy life these day's by the sound of it!! Copper straps have been spec'ed by the manufactures of metallic trunking ever since i can remember, it make you wonder why these manufacturers bother to make/provide them for their trunking systems. I have always added two, and I don't care what the Reg's state or don't state. If a job's worth doing, it's worth doing to the best possible standard!! And any metal containment system that I'm involved with, won't have any need for separate CPC's to be pulled in either!!

 

[D Skelton]

I have always added two

Well I've always added three! Mehhh

 

[Adam W]

I don't think I've ever seen them specced, although I've never installed a trunking system which relied on the containment as a CPC. Of course it still needs to be continuous, but if you bolt it all together properly it should be continuous anyway.

 

[Spoon]

Look at this;

http://www.electriciansforums.net/commercial-industrial-electrical/70927-tray-bonding.html

Post 19.

 

[Engineer54]

I don't think I've ever seen them specced, although I've never installed a trunking system which relied on the containment as a CPC. Of course it still needs to be continuous, but if you bolt it all together properly it should be continuous anyway.

Then you have never been on a fully spec'd project then. Every metal trunking manufacturer either supplies at least 2 copper links with each length, or at the very least has them listed as an installation accessory...

You make it sound as if the use of metal containment system, for CPC requirements is bad practice or inferior. It's neither, in fact the metal containment alone, will be far more superior than the daft CPC's your pulling into that containment system.

 

[oldtimer]

14TH Edition all connectors should be Electrically & Mechanically Sound fine so a 2x2 trunking has a slightly smaller 2x2 joint piece then the 15th edition came out and thats when this nonsense started about earthing things a copper link is not better than a 2x2x4 joint piece . On one job they had me putting an earth link off cable tray onto the wall bracket is sat on as the 15th edition was high on earthing due to the introduction of plastic but what spark in his right mind put a plastic joint piece in a metal trunking.

 

[Adam W]

You make it sound as if the use of metal containment system, for CPC requirements is bad practice or inferior. It's neither, in fact the metal containment alone, will be far more superior than the daft CPC's your pulling into that containment system. lol!!

Somehow I knew you were going to say that.

 

[johnboy6083]

Anything for an easy life these day's by the sound of it!! Copper straps have been spec'ed by the manufactures of metallic trunking ever since i can remember, it make you wonder why these manufacturers bother to make/provide them for their trunking systems. I have always added two, and i don't care a rat's arse what the Reg's state or don't state. If a job's worth doing, it's worth doing to the best possible standard!! And any metal containment system that i'm involved with, won't have any need for separate CPC's to be pulled in either!!

I respect your knowledge and opinions, but im damned if I can explain why a small copper link which is bolted to steel is any better than a full sized joining insert that is supplied with the trunking. Legrands salamandre trunking is one example. For another example, think back to English Electric busbar trunking. This is before my time, but I have inspected/tested and installed systems using this gear. Its solidly built, but does not come with a separate earth busbar like many modern panels/MCCs do. It relies on the chassis of the trunking as its CPC. As I sure you are aware, this trunking comes in sections, which are bolted together. I've not yet found one with links across the joins. I can confirm however that they do stand upto the testing, even after 30-40 years of operation in damp environments. Ive even seen burnt out switchgear which has been removed from said trunking, whilct the trunking itself was fine (just after main ACB, so the fault current was about 20kA). Im all for reasoned argument, but why spec a link across a solid joiner (the same goes for tray too) when it is not required, and brings no benefit to the installation. In the case of fresh air joins (which I despise by the way), then I would use a link/ flylead every time. Also how many sparks actually spray the hole they drilled to fix the link on the trunking. I don't, because I don't use links. The solid joiners however have pre-drilled holes, the trunking/tray has pre drilled holes, and therefore corrosion of the join is no problem.

 

[oldtimer]

My thinking is if I remember right the 15th edition was rolled out to managers only at the time and I remember my gaffer not manager saying bl00dy earthing and I suspect this was because of the introduction of plastic equipment ie trunking,conduit,water/gas pipes. Then the urban myths came about because a minority held the knowledge and in my view got it wrong hence why the OTT on earthing when it first came out.

One thing for sure it only highlighted just how poorly we roll out change and the new ISI&TEE COPs proves this

 

[somersetsparks]

for the sake of a tiny, extremely easy to install copper link, we always put them in specced or not, however on most jobs its a favourite to be picked up for snagging!

 

[johnboy6083]

very true, it is. Most people carrying out snagging don't seem to know what they are talking about in my experience. They have a list of requirements in the spec, and off they go. It doesn't matter to them that you might actually be right!

 

[rmc86uk]

The company I work for always order copper earth straps when installing trunking. A bloke for another firm on the job said he hasn't installed copper earth straps for about fifteen year so I suppose it's down to company preference.