G78

Nightmare1308 · Feb 11, 2017

Is any one here educated on G78 regulations?
Finding it difficult to get information on it, Spoke to national grid and the DNO and neither are helpful on our side of the water.
NICEIC are also struggling.

The Ghost · Feb 11, 2017

https://library.ukpowernetworks.co....e+Stations+mounted+on+Transmission+Towers.pdf. Any good?

Nightmare1308 · Feb 11, 2017

Vortigern said:
https://library.ukpowernetworks.co....e+Stations+mounted+on+Transmission+Towers.pdf. Any good?

Hi thanks for repling.
I already have this and the other 4 areas for the networks but it doesn't specify our side of the install just there side.
I'm looking for the Earthing size needed from the Pylon to the MPBS as you are not allowed to use DNO earthing within the ROP ZONE.
Which then leads to needing to know the minimum size earth for all other extraneous and exposed conductive parts, on top of the platform/suspended floor.
Also the earthing size for the SA1,2,3 suppressors protecting the platform supply and load side, which also cannot be mixed in with the Pylon earth or the Rop zone depending on which side of the suppressor.
Currently using the 70mm AWG earth for whole site but nothing is specifically designed for us. Just wanted to know incase I'm over spec.

The Ghost · Feb 12, 2017

To be honest this is an area I have zero knowledge or experience. I do think it is a bit crazy this area is not clarified by the equipment manufacturer. I guess if its from an overhead supply, or even if it is not you have considerations of lightining strikes as well. I was wondering if any of your team have any knowledge of that area or whether it might profit you to discuss that with one who does. Just a shot in the dark there!

Nightmare1308 · Feb 12, 2017

Vortigern said:
To be honest this is an area I have zero knowledge or experience. I do think it is a bit crazy this area is not clarified by the equipment manufacturer. I guess if its from an overhead supply, or even if it is not you have considerations of lightining strikes as well. I was wondering if any of your team have any knowledge of that area or whether it might profit you to discuss that with one who does. Just a shot in the dark there!

Yes I fit lighting protection (LP) on all sites along side surge protection to conform to LP standards which is another book. As niceic said it's departure from BS7671.
I have a a bit of knowledge about it and what's expected from sites I've visited alot across the country but everyone I go to seems to be different and I want to know what's right and wrong.
it Just seems to be a grey area on somthing that's so dangerous.
I've chased the DNO and national grid as they own certain pylons but neither were any help. Guess I'll keep chasing until I find someone who knows. I'll ping and email to them all Monday morning.

Thanks for you honestly and help.

The Ghost · Feb 12, 2017

http://www.spenergynetworks.co.uk/userfiles/file/OHL-02-015 Issue 2 - G78 COP- LV Supplies to Equip Assoc.pdf You got this one? Seems like you are right on with CSA of earth?

Nightmare1308 · Feb 12, 2017

Vortigern said:
http://www.spenergynetworks.co.uk/userfiles/file/OHL-02-015 Issue 2 - G78 COP- LV Supplies to Equip Assoc.pdf You got this one? Seems like you are right on with CSA of earth?

No that's a different one to the one I got for them. That one makes more sense and it also come inside of bs7671 with the 35mm earthing on bonding size as specified in the regs saying no equipotencial earth shall ever need to be greater than 35mm.
Need to find the writer of the documents who made the standard as they should then know i hope.
Appreciate your help and time.
Thing is I've met other eletrician carring out the works and they said they don't even know and I would like to for my own sake.

The Ghost · Feb 12, 2017

Yeh well best of luck with that. I think you are absolutely right you just can't be working blind on a project with those onerous voltages/dangers.

Roscoe · Jun 18, 2020

Nightmare1308 said:
No that's a different one to the one I got for them. That one makes more sense and it also come inside of bs7671 with the 35mm earthing on bonding size as specified in the regs saying no equipotencial earth shall ever need to be greater than 35mm.
Need to find the writer of the documents who made the standard as they should then know i hope.
Appreciate your help and time.
Thing is I've met other eletrician carring out the works and they said they don't even know and I would like to for my own sake.

Hi Nightmare 1308

Do you still have the PDF for this?