The Siemens 5SN6020-7CN is a SENTRON-series 1P+N miniature circuit breaker rated 20 A at AC with a C-curve trip characteristic and 6 kA breaking capacity per EN 60898. It switches both phase and neutral, with the neutral pole switching but not protecting — the overcurrent trip is on the phase side only.
Where it fits and how it mounts
It mounts in any position, which helps when you're packing a tight enclosure. The IP20 rating applies with conductors connected — fine inside a distribution board but not for wet locations.
Thermal derating and environmental limits
At 40 °C it derates to 18.8 A, and at 45 °C to 18.2 A — so if your panel runs hot, size the upstream protection accordingly.