Replacing Main Earthing Conductor

[Clink]

This may be a newbies question but the older and wiser (or at least the more experienced) heads out there may be able to help....

Just inspected a clients house and amongst the, many, problems it only has a 6mm Main Earthing Conductor. I intend to upgrade it to 16mm but I can't see how to access the earth connector in the supplier's service head. Do I really need to contact the DNO to upgrade an earth? This seems excessive and possibly expensive.

 

[Richard Burns]

The earth cable from the DNO head to the main earth terminal is the DNOs property and should not be changed by you.
You could ring the DNO and say that their earthing conductor is not suitable for the load but I would check this carefully with the adiabatic equation before you ring other wise you would be charged .

 

[Clink]

Thanks Richard, that's confirmed what I thought, I'll go back and check the sums but I'm pretty sure that they are correct. It does make it potentially an expensive bit of cable though.

 

[Lew0125]

Just so you know. Underneath the main fuse, is a flat head screw undo that until you can slide the cover to the right. There will be the earth connections.

 

[Knobhead]

If it shows no sign of stress, leave it alone.

 

[Deleted member 26818]

What is the earthing system?

 

[Engineer54]

What is the earthing system?

If the earthing conductor is entering the Service head, it's pretty sure that it's a PME connection...

 

[Deleted member 26818]

Sorry Engineer54, but making the assumtion that it is TN-C-S just because the earth conductor enters the head is not really enough.
Many heads require that a link be connected inside the head to connect the neutral and earth.
It may be that this is a conversion that took place when 6mm² was the requirement, or may be that it is a TN-S system where 6mm² is still the correct CSA.

 

[dagrat]

As above, do the adiabatic. you will probably find that 6mm is adequate. If so leave it in

 

[Hiddo]

Have you measured the ZE? That's what the DNO will do and if they find the reading to be acceptable then they will say its OK.