ELZ4742 said:Spark123 said:A TN-S system with 25mm² requires a main earthing conductor of 16mm² (table 54G) therefore the main equipotential bonding conductors need to be a minimum of 8mm², the next size up being 10mm².
does it have to be 25mm?
Depends on the size of the supply.
If you work it out for 16mm² you will still end up with 10mm² MEBs.