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

[westward10]

That Table is not for thermosetting which I suspect yours is but I must admit I don't know if this is a factor. What was it you asked the NICEIC.

 

[ipf]

you guys really know your stuff !!

No doubt, but, as said previously, with such a job, which is obviously important and could have a major affect on future work, I wouldn't be taking any chances. Get the job spot on...dig?

 

[westward10]

Even if it’s 84mm
84/8.5= 9.88
So it’s still under 10mm tho it’s dam close and maybe nitpicking a bit.

I always use 8.8 as it allows discrepancies of the armour make up between manufacturers.

 

[KEV 1 N]

I once came across a 95mm 4 core SWA (installed 2007) where which was ran underground in a duct from a substation, ran downhill to a building. Where it was glanded into the section board was completely corroded as were the SWA armouring strands, could only presume the outer insulation was damaged during installing in the duct, and water has got in, and wicked its way out of the gland...luckily there was a separate earth cable installed.
If your cable was running through another building to the new one, then there's no chance of corrosion to the armour, however as it's ran underground and was installed by builders, who may not have took precautions to prevent damage to the cable.....

 

[andysparkfree]

so to recap so I'm sure

we are saying that the swa won't meet the required csa in copper for bonding
and that obviously not running in the cable that i can not say on its condition which puts even more doubt on the above

 

[Leesparkykent]

I would take an educated quess at the SWA being XLPE and not pvc/pvc...I can't remember the last time I had pvc/pvc swa from a whole salers. Regardless of being XLPE or PVC it's not adequate for bonding if you follow the guidance provided to us.....so it amazes me the NICEIC have given you a blanket statement saying it's adequate.

 

[Ian1981]

Perhaps they ment it was adequate for use as a cpc?

 

[ipf]

Once installed a 50mm 4c, OK for 6 months and then blew.... water through an indentation caused by builders digging machine. water and copper shrapnel blew back through the centre of the cable to the supply fused switch. Wet through and messy. Must have been bubbling a while and probably providing underground heating for the cobbled drive.

 

[Leesparkykent]

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?

 

[westward10]

Perhaps they ment it was adequate for use as a cpc?

Agree which is why I asked what exactly he asked the Brains Trust.

 

[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