Down Conductor System

Essentially, the concrete steel reinforcing of the structure was utilised as natural down conductors, in order to ensure electrical continuity between the reinforcing an additional 50mm² galvanised steel down conductor was cast into each concrete column where a down conductor was required.

In accordance with a lightning protection level IV system the maximum spacing between down conductors does not exceed 20 metres apart. Additional down conductors were strategically placed where additional bonding was required. The down conductor locations are marked with an ‘X’ on the design drawings.

Down Conductor System

• If the air-termination consists of rods on separate masts (or one mast) not made of metal or interconnected reinforcing steel, at least one down-conductor is needed for each mast. No additional down-conductors are required for masts made of metal or interconnected reinforcing steel.
• If the air-termination consists of catenary wires (or one wire), at least one down-conductor is needed at each supporting structure.
• f the air-termination forms a network of conductors, one down-conductor is needed at least at each supporting wire end