What is a Down conductor?
A Down conductor is a part of an external Lightning Protection System that is designed as the shortest and the most direct dedicated path to conduct the lightning current from the air terminal safely into the mother earth. The down conductors should be laid at regular intervals for providing multiple parallel current paths for the lightning impulse current. The routing should be as straight as possible with least number of bends and joints. Also, equipotential bonding is to be done to those parts of the structure that are conductive.
What is the need for multible down conductors?
The Lightning protection Standard IS/ IEC 62305 - 3 states that at least 2 down conductors are required for a non- isolated LPS and sometimes it requires multiple down conductors. The proper positioning of down conductors reduces the risk of side flashing and electromagnetic interferences.
The distance between the down conductors depends on the level of protection. The distance provided by IS/IEC 62305 for different levels of protection are tabulated below.
For an isolated LPS, at least 1 down conductor is required for air termination consisting of rods on masts made up of metal or reinforcing steel.
Follow Us