The system in our house at the moment lacks any earth bonding for the water and gas mains. Aiming to rectify this soon.
We have a TT system. I know that a minimum 6mm^2 earth conductor is specified, but I was wondering under what conditions I might want to specify larger.
The water main is near (say a 5m cable run I guess) the gas main is a longer and much more awkward run at least 20 M.