- The J600 product line consists of thermal magnetic circuit breakers, magnetic circuit breakers and molded case switches rated up to 600 A and 600 VAC. These breakers are available with either non-interchangeable trips (designated type TJJ) or interchangeable trips (designated types TJK/THJK). Type TJJ devices ship fully assembled while types TJK/THJK ship unassembled unless specified on the order. TJK breakers are available in two frames, 400 A frame (125 to 400 A) and 600 A frame (250 to 600 A). Trip units are not interchangeable between frames. The WL catalog number suffix indicates that the devices come with Cu/Al line and load lugs.