Earth for new CU

[JTM]

Hi,

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?

John

[js.b1]

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 (=A32-4 off Ebay) to fancy brass type mounted on Phenolic (=A320). 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?

[Andrew Gabriel]

You should take it to the system's main earthing terminal. That might be in the first CU, or it might be separate. It's the point where all the service cross-bonding, the earth(s) from the circuits, and the earth connection from the supplier or earth rods (via a Voltage Operated ELCB if fitted) are all connected together.

You need to bring the whole system up to current earthing standards too, if it isn't already (including replacing any Voltage Operated ELCB with RCD(s)), and test the effectiveness of any earth rod(s).

[John Rumm]

If this is a TT setup (which it sounds like) then you normally connect each CU to your main earth terminal. If you only have one CU then this is usually the earth bus bar in the CU. With multiple CUs its usual to have standalone terminal that then it connected to each CU, the earth rod and the main EQ bonds.

[george [dicegeorge]]

Like this one?

WAY EARTH / NEUTRAL METAL CONNECTOR / TERMINAL BLOCK

[g]

[Andrew Gabriel]

Yes, but should be significantly cheaper than that.

[Styx Lawyer]

>

CPC is nearly always a lot cheaper than anything on Fleabay.

[John Rumm]

>> 8 WAY EARTH / NEUTRAL METAL CONNECTOR / TERMINAL BLOCK

Yup that's the thing.

[JTM]

This is France. All water pipes are PER and gas tank has its own earth spike.

Tks.

[John Rumm]

Note that I know nothing of local practice there - so treat my comments with suitable caution.