When installing a new EV charging point our installers will need to complete a few safety checks, one of these is checking for earth/main bonding. These connections are made to prevent a dangerous voltage between two accessible metal parts, in case there is a fault.
An easy way for you to check if your gas and water supplies are bonded is to check the supply meter box for gas, and your incoming mains water supply near the stop-cock.
You are looking for green/yellow wires connected to the main gas and water pipes using an earthing/bonding clamp.
