What this 2-pole C-curve 20 A MCB brings to a panel
The Siemens 5SJ6220-7 is a 2-pole SENTRON miniature circuit breaker with a C tripping characteristic rated at 20 A and a 6 kA breaking capacity per both EN 60898 and IEC 60947-2 at 400 V AC. The 2-pole format takes up 2 width units (about 36 mm) on the DIN rail — a compact footprint for a 20 A branch circuit. The DC side is rated 60 V maximum, so if you're protecting a 48 V DC control bus or a solar combiner box, confirm the voltage stays under that ceiling. Mechanical service life is 20 000 switching cycles typical — fine for panel isolation duty; not a daily-operate disconnect.
Environmental and mounting specs
IP20 with connected conductors (finger-safe terminals) is standard for enclosed panels; the sealable option lets you lock the toggle position after commissioning. Vibration resistance tested to 50 m/s² at 25–150 Hz and 60 m/s² at 10–150 Hz per IEC 60068-2-6 — it holds up on conveyor drives or machine-mounted sub-panels without loosening.