The Siemens SENTRON 5SP3716-3 is a 1-pole main miniature circuit breaker with an E tripping characteristic, rated 16 A at 230 V AC, 50 Hz. The E curve is a slower trip than B or C, designed for transformer inrush or motor-start loads that would nuisance-trip a faster breaker.
At 1.5 modular width units, it's narrower than a standard 2-module breaker — useful when packing more circuits into a sub-distribution board. The enclosure depth is 76.3 mm; height is 128 mm. IP40 with conductors connected, so it's fine for indoor panels but not washdown zones.
Rated for 20 000 mechanical operating cycles — a solid service life for a main breaker that sees infrequent switching. Shock-rated to 30 g (3 impacts, 11 ms duration) and vibration-tested to 2 g per IEC 60068-2-6, so it holds up in transport or seismic zones.
Locking and safety features
Integrated locking slide accepts a padlock, wire seal, or cable tie — useful for lockout/tagout on the main disconnect in residential or light commercial panels. The switch position indicator shows green for OFF, red for ON, so a quick visual check confirms isolation. Infeed can be at the box terminal from any direction, which simplifies wiring in tight enclosures.