What this 4-pole C-curve MCB does in the panel
Energy limiting class 3 means it restricts let-through energy enough to protect downstream wiring and connected equipment during a fault. The neutral conductor switching (marked 'N' on the device) is a key detail for panel builders: it means the neutral is opened and closed with the phases, so the downstream circuit is fully isolated when the breaker is off. That matters for maintenance isolation and for loads where a floating neutral could cause damage. The unit occupies 4 width units (roughly 72 mm at 18 mm per unit) on a DIN rail, with an installation depth of 55 mm — standard for this SENTRON 5SQ family.
IP20 protection class is expected for DIN-rail components inside an enclosure; no washdown or outdoor rating. The C-curve magnetic trip operates between 5 and 10 times rated current (200–400 A for the 40 A version), which is the standard choice for general-purpose loads with moderate inrush.