Grounded and ungrounded metal bodies exceeding what vertical length must be bonded to structural steel members?

The requirement for bonding grounded and ungrounded metal bodies exceeding a certain vertical length to structural steel members is primarily determined by the need for electrical safety and ensuring a reliable path for lightning currents. In this context, bonding helps mitigate the risks associated with lightning strikes and electrical surges by providing a low-resistance pathway for potential electrical faults.

When metal bodies reach a vertical height of 60 feet, they are at a significant elevation where the risk of being struck by lightning or experiencing electrical discharge increases. Bonding them to structural steel members at this height ensures that they are properly integrated into the overall grounding system of the structure.

This bonding prevents the potential buildup of electrical charges on the metal bodies, which could otherwise lead to dangerous situations such as electrical arcing, fires, or structural damage. The specific height of 60 feet is recognized as a critical threshold in many best practice guidelines and regulations related to lightning protection systems, making it essential for safety compliance in design and installation.