The National Electrical Code (NEC), also designated NFPA 70, is the model code published by the National Fire Protection Association governing electrical installation in residential, commercial, and industrial buildings. It covers wiring methods, conductor sizing, overcurrent protection, grounding and bonding, equipment installation, and special-occupancy rules. The NEC is updated on a 3-year cycle (most recent: 2026).
All 50 states adopt some version of the NEC, though local jurisdictions can amend it and the specific edition adopted varies by jurisdiction. Electrical permits and inspections verify compliance with the locally adopted NEC version. Major updates (such as expanded GFCI protection, AFCI requirements, and tamper-resistant receptacle rules) come through the cycle and significantly affect installation practice.