The Siemens 4EP3910-7AS20 is a Netzdrossel — a three-phase mains choke (line reactor) rated for 50 A maximum continuous current, 45 A rated, with 0.42 mH inductance per phase.
The screw-type terminals on the main circuit accept lugs or ring terminals; plan for panel space measuring 0.219 m wide by 0.179 m tall by 0.123 m deep. Thermal class B (130 °C) insulation per IEC 60085 means the winding can sustain continuous operation at 40 °C ambient without exceeding its rated temperature rise.
