What the 25 kA breaking capacity means for your panel
The Siemens 5SP3816-2 is a 3-pole SENTRON miniature circuit breaker rated 16 A at 400 V AC with a 25 kA breaking capacity per EN 60898.
Characteristic E — what it changes for coordination
Characteristic E is a selective (time-delayed) trip curve, not the standard B/C/D you see on branch MCBs. It's designed to ride through inrush and short-duration overloads so that a downstream fault clears first — selectivity without a fuse. The 5SP3816-2 holds longer on overload before tripping, which matters when you're coordinating a main breaker with sub-feed breakers in a meter panel or distribution board.
Temperature derating — the real current rating
At 40 °C it derates to 15.2 A, at 45 °C to 14.8 A, at 50 °C to 14.4 A, and at 55 °C to 14 A.
Physical fit — panel and enclosure dimensions
The 5SP3816-2 occupies 4.5 modular width units (MW) on a DIN rail. Overall depth is 89.5 mm; enclosure depth is 76.3 mm. Height is 151.3 mm. Conductor cross-section accepts 2.5 to 50 mm² solid or stranded — enough for the incoming supply cable on a main breaker. Fastening is via busbar, and the box terminal allows infeed from either end. IP40 with conductors connected; sealable with the locking slide, wire seal, cable ties, or Antilux.