73 Bridge Road East, Welwyn Garden City

• Designed both buildings to Lightning Protection Level IV under BS EN 62305-2 and BS EN 62305-3, using natural components wherever the building offered them: the structural frame as the down conductor path, the pile foundations as the earth electrode network, and the roof perimeter handrails as part of the air termination where electrically continuous.
• Installed a 20 x 20 m air termination mesh of 25 x 3 mm aluminium conductor tape on non metallic fixings across both roofs, bonding roof plant, cable trays, handrails and any solar panel frames into the network.
• Provided 16 down conductor positions on Building 1 and 9 on Building 2. At each position we installed a high level and a low level copper B bond with about 6 m of 25 x 3 mm copper tape forming the connection tails, and bonded the low level tail to the pile cap reinforcement.
• Attended site in April 2026 to check continuity of the frame with the main contractor, then returned in May, June and July as the structure and roofs came on line, so each connection was made at the right point in the build sequence.
• Fitted a test joint at every one of the 25 positions so the system can be tested for its whole life. Surge protection was written to the electrical contractor under BS EN 62305-4.

Twenty five natural down conductor positions, 25 pile earth connections and 25 test points across two buildings, with no dedicated earth rod or external down tape. A Lightning Protection Installation Certificate follows the visual inspection, continuity testing and earth resistance testing.