The C254TM200D is a TM-D thermal-magnetic trip unit from the ComPacT NSX100...250 DC range, designed for 4-pole DC distribution applications. Its 200 A rating at 40 °C and 750 V DC operational voltage define the continuous-current ceiling and the DC system voltage it can safely interrupt. The LI protection profile — L for thermal overload, I for magnetic short-circuit — is fixed-function: no electronic adjustment beyond the magnetic pickup range of 5...10 x In and the thermal Ir range of 0.7...1 x In. For a validation engineer qualifying a DC bus or battery string, the fixed long-time delay means the thermal curve is factory-set and traceable — no field-adjustable pot to drift outside the qualified range. That supports the audit trail: the protection characteristic is repeatable unit-to-unit. Pollution degree 3 per IEC 60947-1 and IP40 enclosure suit this trip unit for installation inside a panel — not for outdoor or washdown exposure. The four protected poles (4D,) confirm all four poles are monitored for overcurrent; no pole is left unprotected. Class II electrical shock protection means no protective-earth connection is required on the trip unit housing, simplifying panel wiring for the OEM wireman.
Standards compliance and documentation
This standard covers the interruption performance, thermal limits, and coordination requirements for DC circuits. For a maintenance technician or cross-border trader, the IEC certification means the part is accepted in most global jurisdictions without additional national deviation testing. The manufacturer's standard compliance documentation (declaration of conformity, CE marking) accompanies the unit; RoHS and REACH material declarations are available through the Schneider Electric documentation portal under the ComPacT NSX250 DC series.