The C103MA003 is a magnetic-only trip unit from the Schneider Electric ComPacT NSX series, designed for motor short-circuit protection in AC networks. It carries a 2.5 A rating at 65 °C and fits the NSX100...250 frame. The MA designation means it provides instantaneous magnetic protection only — no thermal overload element — so it relies on a separate motor starter or overload relay for running overcurrent protection. This is standard practice for motor branch circuits where the trip unit handles the short-circuit fault and the starter handles the overload.
The instantaneous pick-up is adjustable across nine settings from 6× to 14× In (15 A to 35 A at the 2.5 A rating). That range lets you set the magnetic trip threshold high enough to avoid nuisance trips on motor inrush (typically 6–8× FLA) while still clearing a bolted fault. The 3-pole 3D protected poles description means all three poles are protected and the trip unit switches the line conductors. The IP40 enclosure rating on the trip unit itself is sufficient for panel-mount applications where the breaker is behind a closed door. There is no earth-leakage protection integrated — that function would need a separate Vigi module or an external RCD.
Motor duty and coordination
This trip unit is specifically listed for motor application (Device application: Motor). The magnetic-only characteristic is intentional: in a motor branch circuit, the thermal overload is handled by the starter's overload relay (typically a TeSys LR or similar), and the trip unit only needs to clear short-circuits. The adjustable instantaneous setting lets you coordinate with the starter's withstand rating. For a 2.5 A motor (roughly 0.75 kW at 400 V), setting the magnetic trip to 10× In (25 A) would ride through a normal start while still protecting the cable and contactor against a phase-to-phase fault.