Square D™-brand I-Line™ circuit breaker power distribution panelboards are for use on AC or DC systems. The panels, labeled cULus (compliance to UL and CSA standards certified by UL) are also Underwriters Laboratories® (UL®) Listed. I-Line circuit breaker panelboards are available as 400–1200A main lugs only and 100–1200A main circuit breakers. I-Line circuit breakers, with their exclusive bus connection design, provide superior reliability and performance advantages. A wide variety of accessories are available for field or factory installation of I-Line panelboards. This I-Line, 3P, circuit breaker has a 300A rated current. This breaker has a breaking capacity of 22 kA@600 VAC operation voltage. This breaker has a thermal-magnetic trip technology. The dimensions are 11 in (H), 6 in (W), 5.84 in (D).