DC distribution breaker for 400 A bus
It breaks 36 kA Icu at 750 V DC across three poles in series per IEC 60947-2, and the same 36 kA at 250 V DC on a single pole. The 4-pole configuration (4D protected poles) suits DC distribution in switchboards or backplate-mounted enclosures where a 185 mm wide footprint is acceptable. The TM-DC trip unit provides L (thermal overload) and I (magnetic short-circuit) protection curves, with no integrated earth-leakage function. Rated insulation voltage is 750 V DC, and the breaker is certified for isolation use per EN/IEC 60947-2 — meaning it can serve as a visible disconnect in a DC circuit when the toggle is in the OFF position.
DC breaking performance and selectivity
The F breaking capacity code (36 kA) is consistent across the DC voltage range: 36 kA Icu at 24–125 V DC on one pole, 36 kA at 250 V DC on one pole, 36 kA at 500 V DC with two poles in series, and 36 kA at 750 V DC with three poles in series. This flat curve simplifies coordination studies — the same interrupting rating applies regardless of how many poles are wired in series for higher voltage. Utilisation category A means the breaker is not intended for current-limiting performance under fault; it relies on the magnetic trip for short-circuit clearance.
Fixed backplate mount, accepts horizontal or vertical orientation. The 45 mm connection pitch aligns with standard Schneider busbar systems. Six auxiliary/communication slots are available for alarm contacts, shunt trips, or power metering modules. At 255 mm high × 185 mm wide × 110 mm deep, the breaker occupies a standard NSX frame footprint. Operating altitude is 0–2000 m without derating; above 2000 m up to 5000 m requires derating per IEC 60947-2. Ambient humidity range 0–95 % non-condensing.