What this 2-pole D-curve MCB does on the rail
The Siemens 5SJ4216-8HG41 is a SENTRON miniature circuit breaker with a D tripping characteristic, rated 16 A at both 30 °C and 40 °C, and derated to 14.4 A at 60 °C.
At 36 mm wide (2 modular width units) and 70 mm deep, it occupies the same footprint as a standard 2-pole MCB — no extra clearance needed behind the rail. The combined (box-clamp) terminals top and bottom accept Cu conductors up to the listed cross-section; tighten to 3.5 Nm.
Production status and sourcing
Listed as current production. The 5SJ4216-8HG41 is a standard catalogue item in the SENTRON portfolio, not subject to a last-time-buy notice.
Temperature derating and continuous load
The breaker holds its full 16 A rating up to 40 °C ambient. Above that, derate linearly: 15.5 A at 45 °C, 15.2 A at 50 °C, 14.8 A at 55 °C, and 14.4 A at 60 °C. If the panel internal temperature runs hot — say, near a transformer or in a sealed enclosure — use the 60 °C figure as the continuous load limit. The maximum operating temperature is 75 °C; minimum storage is -40 °C.
Halogen-free and silicon-free construction, sealable with a lockable cover. Vibration resistance rated at 50 m/s² over 25–150 Hz and 60 m/s² at 35 Hz (4-second dwell). IP20 with connected conductors; IP40 in the handle area. The DC rating is 60 V maximum — suitable for control-circuit protection in a 48 VDC panel, but not for a 125 VDC battery bank.