What this 90 A SIRIUS breaker does on a motor branch
The Siemens 3RV1041-4LA15 is a SIRIUS motor protection circuit breaker rated for 90 A continuous current, sized to protect a 45 kW motor at 400 V AC in AC-3 duty. It combines a thermal-magnetic overload relay and a short-circuit trip in one package, so a single device handles both running overload protection and fault interruption on the motor branch. No ground-fault detection on this variant — that's handled separately if the installation requires it.
Breaking capacity and fault coordination
Rated breaking capacity varies with line voltage: 100 kA at 240 V AC, 50 kA at 400 V AC, 8 kA at 500 V AC, and 5 kA at 690 V AC. Maximum operating frequency in AC-3 duty is 15 switching cycles per hour — fine for a pump or fan that starts a few times an hour, but not for a high-cycling application like a press or a crane.
Mounting and wiring for a panel
The 70 mm width and 165 mm height fit standard motor-starter footprints; depth is 174 mm, so allow that clearance behind the panel door. Main circuit terminals accept solid conductors 2× (0.5…1.5 mm²) and 2× (0.75…2.5 mm²), or stranded 2× (10…50 mm²) and 1× (10…70 mm²). Screw-type box terminals for the main circuit; auxiliary and control circuits also use screw terminals. The auxiliary switch is transverse-mounted and field-addable — the product extension is supported. Front-side IP20 protection means it's touch-safe for the panel interior but not rated for washdown — keep it inside the enclosure.