According to NEC Article 240, specifically section 240. 6 (A), the code lists a set of standard ampere ratings beginning at 15 A for fuses and inverse-time circuit breakers. From residential 100-amp panels to massive 600 amp main distribution panels in commercial facilities, this comprehensive guide will help you understand distribution board types, sizing calculations, and installation requirements to make informed decisions about your electrical infrastructure. What. The amperage (amp) rating on a breaker panel signifies the maximum electrical current the panel can handle. Carefully assessing how many amps are necessary for an electrical panel at your commercial facility is crucial. It helps ensure proper performance and maintain a safe working environment for. A panelboard is a component of an electrical distribution system which divides an electrical power feed into branch circuits, while providing a protective circuit breaker or fuse for each circuit, in a common enclosure. A panelboard services to protect branch circuits from overloads and short. UL Listed for use on systems with up to 200K max. The commonly used values in the table include 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200.