Gentlemen can I offer you a sinario,A medium sized factory with its own sub-station with a couple of transformers (one stand by one duty). The sub is located some 20 meters from the main factory area. Mains gas is also housed in a brick built gas house another 20 meters or so further away from both the factory and the sub station. Mains water is located within the factory area. Also have a boiler house complex that is reasonably close to the sub-station. All or most areas will be very difficult to access, main factory area does have a steel frame construction.Just for good measure they have a couple of diesel tanks (above ground)with electric pumps. The building was once a hospital site that has been chopped and developed over a good number of years. But it has never had any main earth bonding installed.
Given all the above information does any body have any good practical and compliant solutions as to how to install efficient bonding please.