Schneider Electric C40F4TM250D ComPacT NSX250F DC 4P 250 A 36 kA TM-DC Fixed Moulded Case Circuit Breaker

The Schneider Electric C40F4TM250D is a 4-pole ComPacT NSX250F DC moulded case circuit breaker rated 250 A on a TM-DC thermal-magnetic trip unit for DC distribution. Breaking capacity (Icu) is 36 kA DC at 750 V DC across 3 poles in series, with both thermal overload and magnetic short-circuit pick-up adjustable on the trip unit.

Technical Specifications

Certifications & Standards

• EN/IEC 60947-2

Selection Notes

Unlike the AC TM-D trip unit, the TM-DC fits both the thermal overload (Ir, 0.7-1 x In) and the magnetic instantaneous pick-up (2.5-5 x In) with field adjustment, which matters on DC circuits where fault current does not fall to zero each half-cycle and the magnetic trip threshold needs tuning to the installation. The 750 V DC rating is reached with all 3 poles wired in series; pick the 250 A rating to match the DC bus or PV array current, and choose a different sibling in the same TM-DC series for a higher or lower current without changing the 36 kA breaking capacity.