The D curve holds through a 10–20× rated-current surge, so it clears only on a hard fault, not a normal load transient.
The D characteristic (tripping between 10× and 20× In) is the key selection parameter here. At 1.6 A, that means the magnetic trip fires between 16 A and 32 A — enough headroom for a small motor or a bank of LED drivers without nuisance trips. But the thermal element still protects the downstream cable at the continuous rating. Temperature derating is real on this part. The 1.6 A rating holds at 30 °C; at 40 °C it drops to 1.54 A, at 45 °C to 1.5 A, and at 55 °C to 1.43 A. The MCB is rated for ambient up to 55 °C with 95% humidity, so it's fine in a damp basement or outdoor-rated enclosure as long as the IP20 (with connected conductors) is respected. Multi-phase operation is rated at 400/440 V AC; single-phase supply voltage is 400 V AC. The DC rating maxes at 72 V, so this is an AC-primary breaker — don't spec it for a DC distribution bus above that.
Mechanical and panel fit
Height is 90 mm. Mounting position is any, so you can lay it sideways in a shallow enclosure if the DIN rail is oriented horizontally. It's sealable (tamper-evident seal wire can be threaded through the housing), halogen-free and silicon-free — important for clean-room or corrosive-environment panels where outgassing matters. Touch protection is built in; neutral conductor switching is not included (this is a 2-pole breaker that switches both phase conductors but does not break the neutral — verify your circuit topology). For a daily-switched load, consider a contactor or a dedicated switch-disconnector instead.