The PowerPact H-, J-, and L-frame circuit breakers are designed to protect electrical systems from damage caused by overloads and short circuits. L-frame circuit breakers are available with MICROLOGIC electronic trip units only. The amperage ratings of the thermal trip elements are calibrated at 104F (40C) free air ambient temperature. Circuit breakers rated for 100% operation are available but require specially-designed enclosures and 194F (90C) rated wire. Devices with the MICROLOGIC electronic trip unit provide adjustable protection settings for greater system flexibility In addition to electronic protection, MICROLOGIC trip units allow users to monitor both energy and power. PowerPact H-, J-, and L-frame circuit breakers offer high performance and a wide range of interchangeable trip units to protect most applications. Electronic trip units provide highly accurate protection with wide setting ranges and can integrate measurement, metering and communication functions. This PowerPact circuit breaker, is a 300A, and is a 3-pole,with a breaking capacity of 35kA@480VAC rated operatiuonal voltage. With a magnetic hold current of 1500A and a magnetic tripping current of 3000A. This breaker has a thermal-magnetic trip unit technology. This unit mount breaker copmplies to UL, CSA standards. Dinemsions for this product are 12.5 in (H), 6 in (W), 4 in (D), and an ambient temperature rating of 40 C.