Which NEC® table is used to size the system bonding jumper of a separately derived AC system?

The system bonding jumper of a separately derived AC system is specifically addressed in the National Electrical Code (NEC) through Table 250.102(C)(1). This table provides sizing information for bonding jumpers that connect the grounded conductor to the grounding electrode system, particularly for separately derived systems.

The rationale behind using this particular table is that it outlines the appropriate sizes based on the rating of the system's overcurrent protection and the size of conductors. These factors play a critical role in ensuring effective fault current path and maintaining the safety and proper functioning of the system.

While other tables in the NEC serve different purposes, Table 250.122, for instance, relates to equipment ground sizing and does not specifically cover bonding jumpers. Table 300.5 deals with the general requirements for underground installation, and Table 250.66 pertains to the size of grounding electrode conductors, which is not the same as sizing system bonding jumpers. Each of these has its own focus and application, reinforcing the importance of using the correct table for sizing in compliance with code requirements.