The PowerPact. J-frame circuit breakers are designed to protect electrical systems from damage caused by overloads and short circuits. H- and J-frame circuit breakers are available with either thermal-magnetic or Micrologic. electronic trip units. H- and J-frame circuit breakers with thermal-magnetic trip units contain individual thermal (overload) and instantaneous (short circuit) sensing elements in each pole. The amperage ratings of the thermal trip elements are calibrated at 104.F (40.C) free air ambient temperature. Per the National Electric Code. (NEC.) and the Canadian Electrical Code, standard circuit breakers may only be applied continuously at up to 80% of their rating. Circuit breakers rated for 100% operation are available but require specially-designed enclosures and 194.F (90.C) rated wire. This PowerPact J, automatic switch has a rated current of 250A and has a rated operational voltage of 600VAC. This switch is a 3-pole, unit mount with a breaking capacity of 18kA@600VAC. This product has a magnetic trip unit technology. This switch has a magnetic tripping capacity of 3125A. Dimensions for this product are 7.52 in (H),4.12 in (W), 5 in (D). This switch complies to UL listed, CE & CSA standards.