Types of Building Lightning Protection Systems (BLPS)
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(1) Single protection
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(2) Multiple protection
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Single protection is cost effective, but still there is substantial chance of damage by lightning bolt. There being only single conductor to earth, a substantial part of lightning bolt may still pass through building structure.
With Multiple Protection System, there is very little chance that any appreciable part of lightning bolt will go through building structure. This is due to the fact that there are enough number of parallel paths provided by large number of lightning rods, copper down strips/wires and earth rods, all bonded together at roof level as well as ground level.