Integrator's first look
The 18 mm width (1 MW) and 70 mm installation depth let it drop into a standard DIN-rail enclosure without crowding adjacent poles.
Thermal derating — what the 4 A really delivers
The 4 A rating holds at 35 °C ambient. Above that it drops: 3.76 A at 40 °C, 3.63 A at 45 °C, 3.5 A at 50 °C, 3.36 A at 55 °C, and 3.22 A at 60 °C. If the panel runs warm — say 50 °C inside a sealed enclosure — the breaker's effective continuous current is 3.5 A, not 4 A. Sizing the branch circuit load against the derated figure avoids nuisance tripping on a borderline circuit.
Touch protection is built in — no separate finger-safe covers needed. The sealable design allows panel builders to lock settings after commissioning.