The Siemens 3RV2742-5LD10 is a SIRIUS circuit breaker in size S3, designed for system protection per UL 489 and CSA C22.2 No. 5. It carries a rated operational current of 60 A and a breaking capacity of 100 kA at 240 V AC, 50 kA at 400 V AC — figures that tell you it can safely interrupt fault currents up to those levels without cascading upstream. The thermal overload release handles sustained overcurrent; the magnetic short-circuit trip clears fast faults.
The 60 A rated current sets the continuous load it can carry in a 40 °C ambient — size your motor or feeder branch accordingly. The 100 kA at 240 V AC and 50 kA at 400 V AC are the interrupting ratings; at 400 V the breaker clears 100 kA under AC conditions, so it handles high-fault utility feeds. The 23.5 W power dissipation at AC in hot operating state matters for enclosure thermal management — if you pack several in a sealed panel, that heat adds up. Terminal capacity: main contacts accept 2x (2.5... 16 mm²) solid or 1x (10... 70 mm²) stranded, with M8 screw terminals and a 4 mm hex socket driver. Auxiliary switch extension is supported.
Dimensions: 70 mm wide, 170 mm high, 176 mm deep. Clearance: 70 mm above and below, 10 mm at the sides. That 176 mm depth is the full body — check your enclosure depth before committing. Relative humidity 10 to 95 % during operation.