PME head , builder forgot earth cable , 100amp 3phase supply , 10 bedroom house , 10 bedroom house

[ipf]

The way I see it is the builder sorts his fudge and slaps in a 16mm green and yellow or you make the far end TT. Being a new build you have the opportunity to build a little earth nest if the ground work isn't done...Could you clamp on to some rebar if traditional construction?

Worth thinking about but which is the cheaper. I'd be after a really low Ra, too.

 

[andysparkfree]

no def bonding conductor , but looks like something has been relayed incorrectly , will ring back tomorrow and question them, however if its the case as you guys say ill sum up with the client in which way they want to go earth rod or dig the road up again
im not fussed to much as long as it meets the regs (and all additional material/ labour costs are met

 

[Leesparkykent]

no def bonding conductor , but looks like something has been relayed incorrectly , will ring back tomorrow and question them, however if its the case as you guys say ill sum up with the client in which way they want to go earth rod or dig the road up again
im not fussed to much as long as it meets the regs (and all additional material/ labour costs are met

Personally I don't see why you have to phone back. It's not adequate full stop if it's either pvc or XLPE for bonding if you follow the guidance provided to support bs7671. No to and throwing with the NICEIC tech line will change that fact. You need a solution and that is to install a earthing conductor or if that's not possible due to cost, schedule etc your left with making the House TT. Are you working directly for the client or the builder? Either way I would have a little word with the builder as their fault and solve it together. TT wouldn't be the end of the world if groundwork isn't complete. A couple of earth pits, multiple rods that could be pushed in with a digger bucket if machinery on site, bare conductor linking them and a 16mm green and yellow in to the building. If you went with a couple of 1.2m rods screwed together on two corners of the building and a bare earthing conductor linking them together I bet it would be under £200 in bits and could be put in whilst groundwork was underway..

 

[andysparkfree]

working direct for the builder , and the ground works looked near enough finished apart from the planned new shrubs
i think ill tell them that they have to dig the route up again and get the earth installed, no point blaming the builder , there punishment is undertaking the job twice
and i want to talk to the help desk again to see what they say again ,to if they say something different to before

 

[westward10]

The problem with these helplines and taking their advice is that you need to satisfy yourself through calculation and applying necessary Regulations to prove it is correct. Once you can do this you will never need helplines.

 

[andysparkfree]

yes makes sense

 

[andysparkfree]

so I've just re-rang the NIC and different chap answered , after going through the whole issue again he has said the same again that the 35mm swa steel is more than adequate to be used as a cps and bonding conductor
however i think I'm going to as suggested westward, learn to do the calcs myself
more knowledge is power (or earth in this case)

 

[westward10]

I am most surprised they are giving this opinion. Have they indicated where they have got the 84mm from for the armour and what factor they are applying to it. If you chose to follow their advise you have to satisfy yourself it is correct. I still say their advice is incorrect.

 

[Pete999]

I am most surprised they are giving this opinion. Have they indicated where they have got the 84mm from for the armour and what factor they are applying to it. If you chose to follow their advise you have to satisfy yourself it is correct. I still say their advice is incorrect.

West you should know by now the NICEIC are never wrong

 

[Octopus]

You have to remember that some of the chaps on the helpdesk are not sparks

 

[westward10]

Must admit I find this worrying unless they are misinterpreting the query.

 

[Pete999]

You have to remember that some of the chaps on the helpdesk are not sparks

Perhaps that's why they are called scams, you would have thought the guys at the sharp end (the help desk) would be suitably clued up, qualified Electrical People, well you would wouldn't you?

 

[andysparkfree]

I spoke clearly and slowly

im gona go through my paper works tonight as i think i got a printout that relates to swa armouring that was provided to me by the nic a few months back (admittedly i didn't look at it )

 

[Pete999]

I spoke clearly and slowly

im gona go through my paper works tonight as i think i got a printout that relates to swa armouring that was provided to me by the nic a few months back (admittedly i didn't look at it )

Just checked my notes and found this info a 35mm2 4 core SWA has a steel csa of 78mm2 equivalent to a 25mm2 copper conductor (BS 4567 & 6724) and 84mm2 steel 32.7 copper (BS 6346)

 

[westward10]

Just checked my notes and found this info a 35mm2 4 core SWA has a steel csa of 78mm2 equivalent to a 25mm2 copper conductor (BS 4567 & 6724) and 84mm2 steel 32.7 copper (BS 6346)

You need to know the conductivity of the armour not what it's copper equivalent is and I suspect this is where it is going wrong.