The Siemens 5SL3320-7 is a SENTRON miniature circuit breaker (MCB) with a 20 A rated current at AC, C-curve tripping characteristic, and a 4.5 kA breaking capacity per EN 60898 and IEC 60947-2. This is a 3-pole (3P) unit rated 400 V AC, with a maximum operating voltage of 440 V for multi-phase operation. Wire terminations accept solid or stranded copper from 0.75 to 25 mm², with a tightening torque of 2.5 to 3 N·m on the screw terminals. That's a wide enough range to handle both the feeder tails and the branch-circuit pigtails without an adapter.
Where it goes and what it protects
Siemens rates this MCB for residential buildings and infrastructure — think final sub-circuits in apartment distribution boards, lighting panels, or small commercial loads. It operates in ambient temperatures from -25 to +45 °C, with storage down to -40 °C. The surrounding temperature influence note allows periodic spikes to +55 °C at up to 95% humidity — enough for a non-conditioned electrical room in a hot climate, but not for continuous outdoor exposure. Touch protection is built in on the line-side terminals.