I am working on installation of lightning protection system. I am facing a problem that in NFPA 780 (4.13.1.3) (NEC 250.60) it is mentioned that earthing pits for lightning protection system, pits for telecommunication system, pits for electrical system and pits for instruments should be connected to each other; my problem is that when high currnet is grounded through lighhtning pit it may flow towards the instruments or electrical equipments through interconnected pits so it can cause a damage to the instruments. Please suggest some protection in this regard.
