na2121NA21 Datasheet. Part #: AHNA21. Datasheet: 136Kb6P. Manufacturer: Panasonic Semiconductor. Description: Relay for control panel of 1c 10A, 2c 5A and 1aThe 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