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). Switchboards and panelboards are often called “the guts” of a premises wiring system. For. Power Distribution Board Design refers to the planning and arrangement of electrical components within a panel that distributes electrical power across different circuits. It involves the placement of breakers, contactors, busbars, terminals, protective devices, and wiring in a structured and safe. NEC Article 408 outlines the requirements for the installation, construction, and use of switchboards, switchgear, and panelboards. They gen at all equipment must comply with the appropriate Br for.