On Jul 17, 6:37*pm, JTM wrote:
Thinking of putting in another CU. *Can I take the earth to
the first CU or do I have to take it to the earth rod?

Generally the earth rod 6491X would be taken to your own MET, Main
Earthing Terminal. These are range from a simple nickel plated brass
block with screws (£2-4 off Ebay) to fancy brass type mounted on
Phenolic (£20). Basically if the DNO does not provide you with an
earth (TN-S or TN-C-S/PME) then you provide one yourself AND maintain
it yourself.

You would then run 6491X from your own MET to your CU(s).

Check your earth is of the correct size re regs - 6491X unprotected
loose in the ground is 16mm, in 20mm flexible conduit to the earth rod
cover I would use 4mm which is going to be much cheaper if the run is
long. Also check your MEB, Main Equipotential Bonding, is correct re
bonding to water & gas pipes that enter the house. Since you have a TT
supply, ensure RCD protection is operating correctly.

Is this in France or UK?