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

[Octopus]

Their cock up then

I wonder how this was comunicated? and to who?

 

[andysparkfree]

i actually had no idea they was going to run the cable when we wasn't on site , i just gave them the list to get on site , other than that the removed and replaced a large section of the block paving and slabs
they did well considering how busy that part of the job , just a shame they didn't get it completely right lol

 

[Octopus]

i actually had no idea they was going to run the cable when we wasn't on site , i just gave them the list to get on site , other than that the removed and replaced a large section of the block paving and slabs
they did well considering how busy that part of the job , just a shame they didn't get it completely right lol

So its not their fault then..................

 

[andysparkfree]

so if i tell you that we need a 35mm swa and a 16mm earth run in for the mains , and you only run a 35mm swa and forget the earth even though theres an email trail then I'm guessing its your fault ...... or is it just me

 

[Octopus]

so if i tell you that we need a 35mm swa and a 16mm earth run in for the mains , and you only run a 35mm swa and forget the earth even though theres an email trail then I'm guessing its your fault ...... or is it just me

So what exactly did the email say?

You previously said you gave them a list of what to get onsite ....

My experience of builders leaves me in no doubt, spell it out AND check they understand - and sometimes it'll still go wrong - the only way to avoid issues like this is to supervise/help on the day.

 

[andysparkfree]

i think i started my original question by stating that the builder forgot to run the earth cable , trying to gage a easy result in solving the issue, be it by earth rod or if the builder needs to dig up the road/ earth again.
the builder him-self was the one on my last site visit to show me that his men forgot to run the earth , i confirmed to him ill do some homework and see if its a big issue or if theres an easier route

didn't realise idd have to remember word for word of emails (i do a few ) to provide as evidence ????

and the fact they undertook the works between us on site (1st fix that took 3 to 4 weeks) and our planed return to site to start 2nd fix is just unlucky but i guess worked with there plans

moving on , its now proven that the swa braid is correct for the required bonding earth size so all and all no issues

no blame needed, was about solving an issue , which has been sorted

 

[westward10]

I disagree, the armour is not adequate.

 

[andysparkfree]

whys that ?

I'm only quoting what the NICEIC told me via phone conversation

 

[westward10]

If they told you the armour of that cable is adequate to support bonding they are incorrect.

 

[andysparkfree]

please explain ?

 

[Ian1981]

If your protective bonding conductors require to be sized 10mm copper minimum then if you intend to utilise the armouring of the swa then the sizing must be equivalent of 10mm copper as an example an 85mm steel conductor would meet this requirement as the copper to steel ratio would be 8.5 as referenced in GN8

 

[westward10]

I would like to know where the NICEIC got 84mm from as this goes against GN8 which quotes 79mm and from manufacturers spec I have looked at none are quoted at 84mm.

 

[123]

Have you got it in writing from the NICEIC Helpline that the SWA is adequate for bonding?

Are they also prepared to stand over their calcs if the s**t hits the fan?

 

[andysparkfree]

found this online

 

[andysparkfree]

I'm hopping your wrong , but would be great to be sure either way
I've got a few days before I'm back on site , so time to make sure I'm clear on how to proceed

 

[Wilko]

My GN8 lists 4x35mm swa cable as having 78mm of steel, which is close but no banana. It may be your particular cable has more steel or a better conductivity than average, so it might be worth checking with manufacturer's data for that specific cable?

 

[Ian1981]

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.

 

[andysparkfree]

you guys really know your stuff !!

 

[EbolaSideRoom]

1) I agree with the early post - never trust a third party with this aspect of the installation. It doesn't matter how good we are as installers if the supply is f****d.
2) I'd be inclined (if there really is no possibility of adding an additional Main earth to take advantage of the PME conditions available) to do as Westward10 suggests.
3) If, however the ferret/ terrier/apprentice can be trained to do their duty and get the extra cable installed then surely 16mmsq.csa isn't big enough anyway?

 

[KEV 1 N]

It seems you may be able to get away with using the armouring as your earth conductor, however I don't mean to put doubt (or possibly more doubt) but if the outer plastic sheath has any damage (from sharp stones) moisture may get in and over time and rust, so the conductivity will be reduced. Did the builder lay the cable in a bed of sand, or just back fill with what they dug out?