MAIN EARTH BONDING domestic installation

[piz]

Hello
When we are asked to change a CU i have been told on pme and tns the main earthing conductor is the responsibilty of the electricity board.
so if this is the case why is a 16 mm earth sold on packs of 2meter tails?,
example change board 25mm tails or 16mm if 80amp main fuse 10mm to gas and water but only sometimes 4 or 6 mm main earth do we just record this on an EIC
Cheers

 

[Deservices]

No you should be changing this to 16mm earth. When they say the earth is there responsibility they mean the earth coming in not the earth wire going to the board.

 

[piz]

So from earth comming in say 6mm earth block connected then 16mm from there to the board?

 

[dagrat]

As above, the dno may or may not supply an earth facility but its always up to you to sort one out. You can decide the size of the earth by selection or calculation via the adiabatic equation.

 

[topcat]

DNO only have to provide earth to the instalation not from service head to CU as I understand it.
thats why tails come with earth .

 

[dagrat]

If after contacting the dno they refuse to supply an earth, which does happen, then a tt is the only way.

 

[polo1]

As above, the dno may or may not supply an earth facility but its always up to you to sort one out. You can decide the size of the earth by selection or calculation via the adiabatic equation.

Beat me to it ^^^^^ as the man says!

 

[Deservices]

So from earth comming in say 6mm earth block connected then 16mm from there to the board?

Yes from the earth terminal to the board either 10 or 16 mm depending on tails size but generally i always fit 25 mm tails and 16mm earth.

 

[DurhamSparky]

Who buys packs of 2 meter cables???

That's a screw fix / tool station trick .....

 

[Spazz]

When I do a CU change I always install 16mm or 25mm tails and 16mm earth (25mm for TT).

It is so surprising how many TN-S and TT still have 2mm earths attached.

 

[piz]

CEF special offer

 

[Engineer54]

When I do a CU change I always install 16mm or 25mm tails and 16mm earth (25mm for TT).

It is so surprising how many TN-S and TT still have 2mm earths attached.

Why on earth (excuse the pun) are you installing a 25mm earth conductor from a Rod??

 

[Des 56]

I'm wondering when the thread title will be relevant to the thread

 

[Spazz]

Why on earth (excuse the pun) are you installing a 25mm earth conductor from a Rod??

Because none of the rods around me are buried, they are always exposed and Regs state 25mm for none protected and none buried rods

 

[Spazz]

I'm wondering when the thread title will be relevant to the thread

As said in post 2 - the DNO must supply a suitable earth - if they cant provide one within regs then you must supply a TT rod!
The DNO must only make an earth available (if they can) and it is your job then to ensure the cable between the termination of the DNO and the CU is upto regs