earthing/bonding

[D Brennan]

Hi all wondering if you could clear a few things up for me.

Im re wiring some lighting in a factory, the trunking already exists and is being re-used and is suspended from chains, the trunking is not earthed back to the MET at present, been a while since I've done industrial so a bit rusty, obviously the trunking requires earthing, all is continuous and earth straps in place, question is do i run a separate earth to the trunking or can the cpc be used from my lighting circuit?

Thanks

 

[batty]

I personally would run a bit of 10mm and treat it as extrenuos welcome back Don where have you been.

 

[D Brennan]

been busy mate working the usual, hope ur all well.

Is 10mm not a bit overkill, got a lot or work to be done in the factory and most trunkings are isolated from the MET surely i don't have to run a 10mm to each one :-(

 

[Revved Up Sparky]

If the structural steel is earthed back to the MET, and there is a girder nearby, install an earth strap (crossbond) between trunking and structural steel. If there are other unearthed sections of trunking or tray etc then you could install additional crossbonds, ideally without cutting the earth, just using a stanley knife to expose one inch of conductor and wrap it around each bolt + washer and then continue on to the next section........ and not forgetting to affix safety tags to each connection.

 

[D Brennan]

If the structural steel is earthed back to the MET, and there is a girder nearby, install an earth strap (crossbond) between trunking and structural steel.

the structural steel is not bonded as of yet, thats one of my next jobs and questions, may as well ask it in this post, what size bonding for gas/water and structural steel on industrial?

 

[Revved Up Sparky]

the structural steel is not bonded as of yet, thats one of my next jobs and questions, may as well ask it in this post, what size bonding for gas/water and structural steel on industrial?

I have'nt got the regs with me but I would probably go for a CSA that was at least 50% of the size of the main earthing conductor.

 

[steptoe]

and,

it may well depend on both the incomers and the supply type.