Which table of the NEC® is utilized to size the main bonding jumper?

The correct reference for sizing the main bonding jumper is found in Table 250.102(C)(1) of the NEC®. This table provides specifications for the size of bonding jumpers and grounding conductors used to ensure that the electrical system is properly grounded and that any fault currents can be effectively managed.

Understanding the context of this table is essential, as it pertains specifically to the main bonding jumper used in the grounding of electrical systems. It takes into account the largest ungrounded conductor that is part of the service or feeder, which is critical for determining the appropriate size of the bonding jumper to maintain system reliability and safety.

Other tables, while related to grounding and bonding, serve different purposes. For instance, Table 250.28(D)(1) is primarily focused on equipment bonding conductors and their sizing based on various circumstances. Table 250.122 provides guidelines for the sizing of equipment grounding conductors, while Table 250.66 deals with the sizing of grounding and bonding electrodes for larger installations. Each of these tables is important within its context, but none match the specific requirements for sizing the main bonding jumper as outlined in Table 250.102(C)(1). This differentiation is crucial for ensuring compliance with the NEC and for the safety