EICR

[cliffed]

Exactly right,the actual incoming neutral size is 240 mm,which I think gives a Earth bonding conductor of 50 mm.
Interesting to know the C3 code given

 

[westward10]

Hi Cliffed, to clarify - the 4 core 35mm SWA is used to extend the 3 phase service from the TNCS PME DNO cutout. There are no connections to the cutout except via this SWA, so the armour is providing CPC for the SWA and earthing conductor function for the site?

4 core 35mm SWA has steel of 84mm and resistivity ratio given as 8.5 on p60 of GN8 meaning equivalent to 9.88mm of copper. Which means its undersized for current regs, which I think will be 10 or 16 from Table 54.8 (depends on incoming DNO neutral size).

I'm not familiar enough to know if it was sized ok for an earlier edition? In which case it could be a C3 improvement?

I thought the ratio was 8, not at home to check.

 

[westward10]

Exactly right,the actual incoming neutral size is 240 mm,which I think gives a Earth bonding conductor of 50 mm.
Interesting to know the C3 code given

How do you know the supply neutral csa.

 

[cliffed]

How do you know the supply neutral csa.

It's a c/t arrangement & the supply tails to the Main panel are 240 mm & 120 mm main earth.
Main switch rated at 400 amps.

 

[cliffed]

How do you know the supply neutral csa.

I meant neutral size of the outgoing tails,soz

 

[westward10]

I meant neutral size of the outgoing tails,soz

It should be based on the supply neutral but without that info you will have to base it on the earthing conductor.