NEC Article 690

NEC Article 690 is the section of the National Electrical Code specifically dedicated to solar photovoltaic (PV) systems. It provides the detailed electrical safety requirements that every solar installation in the United States must follow.

Article 690 covers a wide range of technical requirements including: maximum system voltage calculations, conductor sizing and protection, disconnecting means (disconnect switches), grounding and bonding, overcurrent protection, labeling requirements, and the critical rapid shutdown provisions (Section 690.12). The rapid shutdown requirement — introduced in NEC 2017 and strengthened in NEC 2020 — mandates that all conductors within the array boundary must be reduced to 80 volts or less within 30 seconds of initiating shutdown. This requirement has effectively made module-level power electronics (microinverters or rapid shutdown devices) standard on all new installations. Article 690 is updated with each NEC edition to reflect advances in solar technology and safety practices. Solar installers and inspectors must be well-versed in Article 690, and electrical plans submitted for permits must demonstrate full compliance.