Schneider Electric – 50440 – MA120 Series Closed Toroid CT, 250 A / 1:1000

The Schneider Electric 50440 is a MA120-series closed-core current transformer (toroid) designed for Vigilohm insulation monitoring and VigiPacT type‑A residual current relays. With a 1:1000 transformation ratio and large 120 mm inner bore, it measures up to 250 A continuously and provides precise leakage/residual current detection in power distribution panels.

 Key Features & Specifications

• Model / P/N: 50440; MA120 toroidal CT, 250 A continuous, 1:1000 ratio

• Inner Diameter: 120 mm (4.72 in) — accommodates multicore cables up to 60 mm Ø  

• Rated Current: 250 A AC; supports residual current protection and insulation monitoring  

• Transformation Ratio: 1:1000; compatible with VigiPacT, Vigilohm, MIS relays  

• Standards: IEC 60947‑2; impulse withstand 12 kV, short-time withstand 85 kA/0.5 s  

• Construction: Closed toroid, screw terminals; 0.45–0.6 kg depending on spec  

• Temperature Rating: –35…+70 °C; storage down to –55 °C  

• Certifications: UL, CSA, CE listed for industrial panel use