16mm or 6mm

[Buzz-light-bulb]

Hi all

Im currently on with a condition report and it's a tn-s earthing arrangement with a 6mm coming off the sheath into an earthing block then a 16mm from there to the cu, now would you put 6mm as main earthing conductor as this is worse case or 16mm as it goes into the board. Or shall I put my tin hat on

 

[Buzz-light-bulb]

Lol just spoke to them again and got a more definitive answer and that is 16mm as this connected to the main earthing terminal

 

[Hawkmoon]

lol I think this is all matter of opinion stuff - ask them 'what if MET is in CU?'

 

[Zebra Stripe]

Well according to their (NICEIC) "definitive" interpretation....if the MET is in the CU, you wont have an Earthing conductor:rolleyes2:

Surely the "means of earthing" is generally either:
a) supply sheath,
b) neutral solid link or
c) earth rod,
therefore if the earthing conductor is "that which connects the MET to an earth electrode or other means of earthing" Definition BS7671

then the earthing conductor has to be in this instance the 6mm..ie the conductor from MET to the joint on the sheath...the joint on the sheath is theirs (DNO) and they can keep it.

 

[Buzz-light-bulb]

Well according to their (NICEIC) "definitive" interpretation....if the MET is in the CU, you wont have an Earthing conductor:rolleyes2:

Surely the "means of earthing" is generally either:
a) supply sheath,
b) neutral solid link or
c) earth rod,
therefore if the earthing conductor is "that which connects the MET to an earth electrode or other means of earthing" Definition BS7671

then the earthing conductor has to be in this instance the 6mm..ie the conductor from MET to the joint on the sheath...the joint on the sheath is theirs (DNO) and they can keep it.

Yes this is correct as there is a met between the service head and the cu.

 

[Hawkmoon]

Yes this is correct as there is a met between the service head and the cu.

Not quite sure what you're getting at there Buzz

 

[Guest55]

page 37 of the current bs7671 is clear as crystal if you ask me............

the conductor to the MET from whatever supply type is present is the "main" earthing conductor

the 16mm from MET to CU is actually a circuit protective conductor.

why guess when you can simply look up the facts...........


;-)

 

[Guest55]

but i still wouldnt give a eicr defect code to an undersized conductor that is outside the consumers jurisdiction , just wouldnt be cricket would it ?

:-D

 

[Buzz-light-bulb]

Yes this is correct as there is a met between the service head and the cu.

Not quite sure what you're getting at there Buzz

The main earthing conductor which has already been stated many times is between the service head and the earth block (met) then the 16mm goings from there to cu, I believe that's a slam dunk

 

[GLENNSPARK]

So, he's doing an EICR, so theses are not irrelevant. TIf the Ze is within tolerance and the 16mm is from the CU. I wouldn't code it as its OK. IMH

no.

its like saying `well theres a bit of 16mm there.....but the bit where it drops to 6mm is irrelevent`..

worst case : 6mm...i would give this one a 2

sometimes i have come across where there has been 2X 10mm G/Y used as the main earthing...
i would put that down as 10mm/10mm...perfectly acceptable as long as run together and prefably taped/tiewrapped together along their run= no code..

 

[Buzz-light-bulb]

So, he's doing an EICR, so theses are not irrelevant. TIf the Ze is within tolerance and the 16mm is from the CU. I wouldn't code it as its OK. IMH

no.

its like saying `well theres a bit of 16mm there.....but the bit where it drops to 6mm is irrelevent`..

worst case : 6mm...i would give this one a 2

sometimes i have come across where there has been 2X 10mm G/Y used as the main earthing...
i would put that down as 10mm/10mm...perfectly acceptable as long as run together and prefably taped/tiewrapped together along their run= no code..

Why would you give it a code 2, if calculated using the adiabatic equation and all is sufficient then it wouldn't warrant a code 2

 

[Amp David]

I'd use the adiabatic on this one then take it from there

 

[GLENNSPARK]

Why would you give it a code 2, if calculated using the adiabatic equation and all is sufficient then it wouldn't warrant a code 2

OK....there is the adiabatic....

 

[GLENNSPARK]

bus some of the stuff i was reading...

i mean the DNO have made their equipment available for the means of earthing....but who`s responsibility is the MET?...not the DNO....