NA21 Datasheet,

na2121NA2121-20. NA2121-21. Dimensions (mm) 340×256×54. Hole size (mm) 330×246. Display size. 12.1(Length: width = 4:3) Weht (g) 2160. Working temperature. 0℃～55℃(No freezing)The relay type NA21 is typically used in HV, MV and LV radial networks as feeder or power transformer protection. In solidly grounded systems the residual