Article 250 is a foundational pillar of NFPA 70®, National Electrical Code® (NEC®), and the tables within Article 250 are critical resources for sizing the wiring for the grounding and bonding of an electrical system. Becoming more familiar with the proper use of these tables can help installers ensure effective grounding and bonding on their projects and, in turn, help ensure the safety of those within the building.
This free resource provides access to the following tables from the 2020 edition of the NEC, along with table tips and application examples for using each table.
- Table 250.66 —Grounding Electrode Conductor for Alternating-Current Systems
- Table 250.102(C)(1) — Grounded Conductor, Main Bonding Jumper, System Bonding Jumper, and Supply-Side Bonding Jumper for Alternating-Current Systems
- Table 250.122 — Minimum Size Equipment Grounding Conductors for Grounding Raceway and Equipment