What this 4-pole B-curve MCB does in the panel
It's a 3P+N configuration with a switched neutral, rated 10 A at 400 V AC with a B-curve trip characteristic (trips between 3 and 5 times rated current, so it's the go-to for resistive and general-purpose loads in residential and infrastructure builds). The neutral pole switches with the phases, so you get full isolation on all four conductors when the breaker is off — no separate neutral bar needed downstream. Rated for 10 000 mechanical operating cycles typical, and it's sealable for lockout/tagout compliance.
Thermal derating — the real-world current limits
Push the panel ambient to 40 °C and the continuous current drops to 9.52 A; at 45 °C it's 9.2 A; at 55 °C it's 8.74 A. The breaker itself is rated for a maximum ambient of 75 °C and a minimum of -40 °C, with periodic humidity up to 95 % at 55 °C. That's a wide environmental envelope — it'll handle unheated electrical rooms and outdoor-adjacent enclosures without complaint.
The 72 mm width (4 MW) means it occupies four 18 mm module spaces. IP20 with conductors connected, so it's for enclosed distribution boards, not open-panel washdown areas. Touch protection is built in on the line-side terminals.