The Siemens 3RV2742-5AD10 is a SIRIUS circuit breaker in the S3 frame, designed for system protection per UL 489 and CSA C22.2 No. 5. It carries a rated operational current of 10 A and operates at 50/60 Hz with a rated voltage range of 20 to 600 V. The overload release is thermal; the short-circuit trip is magnetic. Breaking capacity reaches 100 kA at 240 V AC and 50 kA at 400 V AC (with an alternative rating of 100 kA at 400 V AC also listed). The S3 frame size and M8 main-contact terminals handle solid or stranded conductors up to 70 mm² (single) or 50 mm² (double). Screw-type terminals with a hexagonal socket (4 mm tip) are standard.
The 100 kA breaking capacity at 240 V AC and 50 kA at 400 V AC (with a second entry showing 100 kA at 400 V AC) means this breaker can safely interrupt fault currents up to those levels without upstream devices needing to clear first. The thermal overload release (rated 10 A) protects against sustained overcurrents; the magnetic short-circuit trip handles instantaneous faults. The 25 000 typical mechanical/electrical cycles for main and auxiliary contacts give a baseline for maintenance scheduling in high-cycle applications like conveyor or pump control.
Mounting and integration — DIN-rail fit and clearances
Dimensions: 70 mm wide, 170 mm high, 176 mm deep. Required clearances: 70 mm above, 70 mm below, 10 mm to the side. These clearances are for heat dissipation and arc venting — respect them in a crowded enclosure. Terminals accept solid or stranded copper: 2x (2.5 to 16 mm²) for the control circuit, and up to 1x (10 to 70 mm²) or 2x (2.5 to 50 mm²) for the main circuit. AWG 14 solid fits the front clamping point only. The hexagonal socket screwdriver tip is 4 mm.
Relative humidity during operation: 10 to 95 %. The substance prohibition date (RoHS/REACH compliance) is March 1, 2017. No ground-fault or phase-failure detection built in — those functions require an external module or a different breaker variant.