What the D-curve and 16 A rating mean on a motor or transformer circuit
The 5SY4316-8: The D curve means the magnetic trip is set to 10–20× In — it holds through the inrush of motor starters, small transformers, or discharge lamps without nuisance tripping, then clears a hard short fast.
Panel fit and mounting constraints
Rated 16 A at 35 °C ambient; derates to 15.23 A at 40 °C, 14.83 A at 45 °C, 14.43 A at 50 °C, 14 A at 55 °C, and 13.57 A at 60 °C. If the panel internal temperature runs hot, the continuous load must be reduced accordingly — the nameplate 16 A only holds below 35 °C. Halogen-free and silicon-free construction — no outgassing concerns in sealed enclosures or clean-room adjacent panels.