What it is and what it does
The Siemens 5SP3316-3 is a SENTRON main miniature circuit breaker — 3-pole, 16 A rated at 400 V AC, with an E tripping characteristic and a 25 kA breaking capacity certified to EN 60898. That 25 kA rating means it can safely interrupt a fault current up to that level without welding its contacts or cascading the fault upstream; it's sized for high-fault-capacity residential or infrastructure panels where the prospective short-circuit current is substantial.
What the E-curve means for your load
The E tripping characteristic sits between the standard C and D curves — it holds through moderate inrush but trips faster than a D curve on sustained overloads. For a 16 A breaker, magnetic trip is typically around 8–14× In, so it's a fit for transformer inrush or groups of small motor starters where a C curve would nuisance-trip but a D curve might delay too long on a hard fault.
Thermal derating — don't ignore it
Rated 16 A at 30 °C, but the continuous current drops to 15.2 A at 40 °C, 14.8 A at 45 °C, 14.4 A at 50 °C, and 14 A at 55 °C. If this breaker lives in a crowded enclosure with other heat sources, size the load against the derated figure for your ambient — not the 30 °C nameplate.
Panel fit and wiring
Snaps onto standard DIN rail (35 mm). Occupies 4.5 modular width units — that's 81 mm of rail space. Accepts solid or stranded conductors from 2.5 mm² up to 50 mm² via saddle terminals; infeed can come from either the top or bottom box terminal. IP40 with conductors connected, pollution degree 3, overvoltage category IV. Integrated locking slide accepts a padlock, wire seal, or cable tie for lockout/tagout.