The Siemens 3RA1110-0ED15-1BB4 is a SIRIUS non-fused load feeder configured as a direct starter, Size S00. It's a pre-assembled combination of a contactor, a bimetal overload relay, and a circuit breaker for short-circuit protection — all in one 45 mm wide package that snaps onto a DIN rail. Rated for 24 V DC control voltage and 0.09 kW at 400 V, it's sized for small three-phase motor loads like pumps, fans, and conveyors in a control panel. The supplied contactor is a 3RT1015-1BB41, the link module is 3RA1911-1AA00, the busbar adapter is 8US1251-5DM07, and the circuit breaker is a 3RV1011-0EA10. That means this is a matched set — no guessing whether the overload relay coordinates with the breaker.
Snap-on mounting to a DIN rail. That's useful when you're shoehorning this into a crowded panel and the rail isn't perfectly vertical. Clearance requirements: 20 mm upwards, 10 mm forwards, 9 mm backwards, 0 mm downwards, and 20 mm at the side. The zero downward clearance means you can butt another device directly below — saves rail space. Dimensions: 203 mm high, 45 mm wide, 128 mm deep.
Wiring and Environmental
Terminals accept solid conductors 0.5 to 4 mm² and stranded 0.5 to 4 mm². For the main contacts, AWG 2x (18 to 14) is specified. The solid range also lists 2x (0.75 to 2.5 mm²) — that's for daisy-chaining two conductors in one clamp, handy for looping control power. Shock resistance is 9.8g. Protection class on the front is IP20 — finger-safe, but not washdown-rated. This lives inside a cabinet, not on the machine face.
No PROFINET or PROFIBUS DP protocol onboard — this is a pure electromechanical feeder, not a fieldbus slice. The no-load switching frequency is 15 1/s, which is fine for motor starting but not for high-speed resistive switching.