Choose the right box based on environment (indoor/outdoor), load capacity, and durability. Check for proper IP/NEMA ratings and material quality. It takes the incoming power and safely distributes it to different circuits throughout your building. However, the key to. Panelboards shall be installed in accordance with the listing of the panelboard. The National Electrical Code (NEC) provides comprehensive safety standards for electrical installations, including requirements for electrical panels (main service panels and subpanels or breaker box). NEC Article 408. he New York city electrical code.