- The top of the ESE must be 5 m above the zone it protects. ( including antennas, cooling towers etc).
- Any receiving antennas (TV, radio, telephone) must be connected to the down conductors via a spark gap.
- The coaxial cables of these antennas must be protected with an appropriate surge protection device.
- Any metallic items that rise above the roof level must be bonded to the closest down conductor.
DOWN CONDUCTOR SYSTEM
- Each ESE must be connected to at least one down conductor. At least two down conductors are required for the following cases:
- If the width and breadth of the structure is larger than the height
- Where the height of the structure is greater than 28 m.
- The two down conductors must be located on the opposite sides of the structure.
- Down conductors must be as straight as possible and the shortest path to the earthing system. Bends not to exceed 20 cm.
- Down conductor must be on the outside of the building and not near electrical or gas pipes.
- An earthing system is required for each down conductor.
- The earth resistance must be less than 10 ohms.
- It is recommended to have an inspection box with a disconnection point such that the earth can be regularly tested.
- It is advisable to cross bond the ESE earth(s) to the structure earth.