Rated for the panel — what the B-curve and 20 A mean on a real line
It is not the right curve for motor starting or transformer inrush (use C or D for those). Breaking capacity is 4.5 kA per EN 60898 and 5 kA per IEC 60947-2. The 4.5 kA figure governs for domestic-style installations under the product standard; the 5 kA rating under the industrial standard gives a small headroom margin for fault-current coordination studies. Either way, this is a standard-interrupting MCB — not a high-breaking-capacity unit for transformer-secondaries or high-fault locations. The 3P+N pole configuration (four modules wide, 72 mm) switches all three phases and switches the neutral — the neutral pole is not protected, just switched. This is common for TN-S or TN-C-S systems where you want to isolate the neutral alongside the phases. Rated voltage is 400 V AC line-to-line, with a maximum of 440 V AC multi-phase.
At 40 °C it derates to 18.79 A; at 45 °C to 18.6 A; at 55 °C to 16.8 A. If the panel runs warm — common in a crowded DIN-rail enclosure — the actual trip threshold drops. For a continuous load near 18 A, a 40 °C ambient pushes the breaker close to its thermal limit. Plan the load at the derated figure, not the catalogue number.
Mounting and integration — DIN-rail, any position, IP20
Width is 72 mm (4 modular width units). Sealable design (can be locked in the OFF position with a padlock hasp).