What this MCB is
The 5SJ4340-8HG41: A 3-pole D-curve miniature circuit breaker from the Siemens SENTRON 5SJ4 family, rated 40 A and 400 V AC / 60 V DC. The D characteristic is made for high-inrush loads — motors, transformers, capacitive feeds — without tripping on startup. Current production, no end-of-life notice. We quote this against your BOM line directly; no last-time-buy concerns.
Three modular width units (54 mm). Ambient temperature range -40 to 75 °C, 95 % humidity. Sealable cover; IP20 with connected conductors, IP40 at the handle. Halogen-free and silicon-free construction.