Siemens SENTRON 5SL3304-7MB — 3-pole MCB, C-curve, 4 A
The Siemens 5SL3304-7MB is a 3-pole miniature circuit breaker from the SENTRON range, rated 4 A with a C tripping characteristic and a 4.5 kA breaking capacity at 400 V AC per EN 60898. This is the part you reach for when protecting a 400 V three-phase branch circuit — lighting, small motor feeders, or control power transformers — where the inrush is moderate and the fault current available at the panel doesn't exceed 4.5 kA. For a 400 V line with a 4.5 kA prospective short-circuit current, this breaker sits right at the rating — no headroom for a larger transformer or a higher-SCCR panel upgrade.
Footprint and panel integration
Mounting position is unrestricted — vertical, horizontal, or upside-down on the rail — which simplifies layout in a crowded sub-distribution board.