The Siemens 3RV1011-1FA20 is a SIRIUS motor protection circuit breaker rated for 5 A continuous current with CLASS 10 trip characteristic, sized for a 1.5 kW motor at 400 V AC. It carries a 100 kA breaking capacity at 400 V AC — that's the fault-clearing muscle that keeps upstream gear alive when a motor winding shorts. Phase failure detection is built in, so a single-phased motor trips before it cooks.
DIN rail fit and panel integration
Snaps onto 35 mm DIN rail per EN 50022, screw or snap-on. At 45 mm wide and 81 mm deep, it leaves 0 mm clearance needed backwards or to the side — you can pack these tight on a rail without derating for air gap. IP20 on the front means it's safe for finger contact inside an enclosed panel; no washdown rating, so keep it behind the gland plate.
Termination and wiring
Spring-loaded terminals on both the main current circuit and the auxiliary/control circuit. Main contacts accept 2x (0.25 to 2.5 mm²) solid or 2x (0.25 to 1.5 mm²) finely stranded with ferrule. AWG equivalent is 2x (24 to 14). No screw torque to check — push the wire in, it's clamped. The auxiliary switch slot is available (product extension yes), so you can add a signal contact without re-terminating the power side.
Breaking capacity and coordination
Breaking capacity drops with voltage: 100 kA at 240 V and 400 V AC, then 3 kA at 500 V, and 2 kA at 690 V. At 690 V AC-3 max, it's still rated — but the fault current it can interrupt is much lower. For a 400 V panel with high available fault current (say 65 kA), this breaker still has headroom. The surge voltage resistance is 6 kV, which covers most industrial distribution.
Sourcing posture
This is a current-production Siemens part, sourced through independent distribution. Availability and current pricing are confirmed at quote time against an RFQ. If you need to fill a BOM line or replace a failed unit in a live panel, send the order code and quantity — we'll quote the best channel.