QO Circuit Breaker Load Centers, QO142M200P, from Square D are Underwriters Laboratories (UL) Listed and CSA rated panelboards. They are designed to meet residential, commercial, and industrial requirements to protect electrical systems, equipment, and people. They are available in both traditional and plug on neutral configurations. There is 3 types of mains available. There is main circuit breaker, main lugs, and generator panel. Single and three phase options are available. The bus bars are tin plated copper and are shielded. Indoor and outdoors enclosures are an option. QO Load Centers enable the use of a full complement of accessories. This 1 phase load center has 42 spaces and 52 circuits. This system provides a 200A convertible main breaker in a NEMA 1 enclosure. This product is UL rated.