You are absolutely correct. A lightning protection system (LPS) needs to be bonded to the building's regular grounding system. This is a crucial part of a complete and effective lightning protection system. The purpose of this bonding is to equalize the potential between the lightning protection system and other grounded systems within the building, minimizing the risk of side flashes and damage.Here's where you'll find that requirement in NFPA 780, Standard for the Installation of Lightning Protection Systems: NFPA 780, 4.14 Grounding and Bonding. This section will direct you through the detailed requirements for bonding. Specific subsections you should look at are: 4.14.1 General. "All grounding electrodes required by this standard shall be bonded together to form the lightning protection system grounding electrode network. The lightning protection system grounding electrode network shall be bonded to any other available grounding electrodes or systems..." 4.14.2 Connection to Other Grounding Systems. Here the code discusses the need to bond the lightning protection system to other grounding systems, such as the building's electrical service ground, metallic water pipes, and other grounded metal components.The key reasons for bonding: Equipotential Bonding

Lightning strikes can introduce massive surges of current into the grounding system. Bonding the LPS to the building's grounding system helps equalize the potential between different grounded components. This reduces the voltage difference between them, minimizing the chance of a side flash jumping from the LPS to other grounded objects (like electrical conduit, plumbing, or equipment).

Current Distribution: Bonding helps distribute the lightning current more evenly through the grounding system. This reduces the current concentration in any one point and helps prevent damage to grounding electrodes and conductors.In summary, while a lightning protection system can have its own ground rods, they must* be bonded to the building's regular grounding system to create a comprehensive equipotential grounding network. NFPA 780, Section 4.14 is the section that covers the requirements. Flag for review