The Siemens SENTRON 5SM9333-6 is an electronic residual current (RC) unit designed to pair with a 5SL4 miniature circuit breaker, forming a combined RCBO in a 3-module-width package. It's a 3-pole, type A device rated at 40 A with a 30 mA trip threshold, operating on 400 V AC at 50 Hz.
The 3 kA surge current resistance means it handles the inrush from capacitor banks or long cable runs without nuisance tripping.
Physical fit and environmental limits
Dimensions: 70 mm depth, 54 mm width, 100 mm height. That's 3 modular width units on a standard DIN rail. The IP20 rating applies only when installed in a distribution board with conductors connected — this is a panel-internal device, not for exposed or wet locations.