The Siemens SENTRON 5SP3320-3 is a 3-pole miniature circuit breaker (MCB) rated 20 A at 400 V AC, with a 25 kA breaking capacity per EN 60898. It carries the type E tripping characteristic — a delayed curve that handles inrush from transformers or motor starters without nuisance trips, while still clearing a hard short fast.
Rated 20 A at 30 °C, the breaker derates to 19 A at 40 °C, 18.5 A at 45 °C, and 18 A at 50 °C. Insulation voltage rated at 690 V, overvoltage category IV, pollution degree 3. That's the heavy-duty end of the residential/infrastructure spec — suitable for main distribution panels where the breaker sits close to the utility transformer and sees dirty power.
Occupies 4.5 modular width units — a bit wider than a standard 3-pole MCB (usually 3 MWUs), so check your DIN rail space before committing. Depth is 76.3 mm; height 128 mm. Accepts solid or stranded wire up to 50 mm², minimum 2.5 mm². Saddle terminals and box-terminal infeed are standard. IP40 with conductors connected; sealable with an integrated locking slide that accepts a lock, wire seal, or cable ties.
Listed as current production. No end-of-life notice or successor has been issued.