The Siemens SENTRON 5SL3320-6 is a 3-pole miniature circuit breaker (MCB) rated 20 A with a B tripping characteristic. It protects branch circuits in residential and infrastructure panels against overload and short-circuit, with a breaking capacity of 4.5 kA per EN 60898 and IEC 60947-2.
Rated 20 A at 400 V AC, this MCB handles a 3-phase load up to roughly 13.8 kW resistive. The 4.5 kA breaking capacity per EN 60898 covers most residential and light commercial fault levels — if your available fault current at the panel exceeds that, you need an upstream current-limiting device or a higher-rated breaker. The B characteristic (3–5× In) gives faster trip on moderate overloads than a C-curve, which matters when downstream wiring or devices have limited short-time withstand.
At 3 width units (54 mm wide, 90 mm tall, 76 mm deep), it occupies the same footprint as other 5SL3-series breakers. Screw terminals accept 0.75 to 25 mm² solid or stranded copper — enough for the 20 A feed. Torque to 2.5–3 N·m. IP20 with conductors connected; mount in any position.