Earthing - TNS Upgrading Existing

[Danny Pross]

Hi
I have come a situation of "upgraded" (16mm and 10mm) earthing and bonding being attached to the original (and much thinner) earth to the supply sheathing.
Apparently the electrician didn't want to interfere with the original earth clamp to the sheath - so connected the old (thin) earth wire to the upgraded ones.
His reasoning was that if the ZE is ok then there is no problem.

I see what he is saying - but it just seems odd to upgrade effectively only part of the earth path.

I would be interested in any comments or advice on this.

Thanks

D

 

[miner69er]

As far as i'm aware, the earth bonding on the sheath is before the meter and as such ownership is that of the supplier. To upgrade this would leave yourself in a very bad position as if there was a problem, you would be at fault and liable. The only course of action can be to inform the supplier and ask to be upgraded, however if the existing Ze reading is good then the supplier may want to charge for the upgrade. Personally i would leave alone as the Ze is good.

 

[lamb]

You cannot interfere with suppliers equipment (anything before the meter).

Therefore, if the Ze is acceptable, and the suppliers Earth Conductor complies with adiabatic requirements, use an Earth Block to connect the consumers installation to this.

I always position my Earth Block right next to the Cut Out and supply cable. This way, the DNO can easily install a spring clamp onto their cable, and the earth braid will easily reach the earth block.

If the Ze is high, phone the DNO or inform in writing.

If the provided Earth Conductor does not comply with adiabatic requirements, tell the DNO by phone or letter that by your calculation their conductor will melt in the event of an earth fault.

 

[Spudnik]

Agree with the above but just to add that if the Ze is too high, then contact the DNO as it is their responsibility to maintain it.