AP7-1-51-302 is a single-pole, fully sealed magnetic circuit protector designed for DC circuit applications with a short time delay characteristic. This hydraulic magnetic circuit protector features a screw terminal configuration with terminal block mounting and combines power switching with accurate, reliable circuit protection and inverse time delay functionality. The unit maintains consistent trip current performance across a wide temperature span, unlike thermal circuit protectors, and provides trip-free operation. The 51 delay code specifies DC short time delay with inrush pulse tolerance of 6 times rated current at 60Hz, making it suitable for applications requiring precise overcurrent protection with controlled response times in DC power distribution systems.