The Siemens 3RT1316-1BM40 is a SIRIUS power contactor in size S00, with 4 normally-open main contacts and screw-type terminals. It is rated for 4 kW at 400 V in AC-2 duty (slip-ring motor starting) and 10 A in AC-12 resistive loads. The coil is a DC-operated economized design — closing and holding power both at 3.3 W DC. Mounting is screw-and-snap-on onto a 35 mm DIN rail per EN 50022, with a 45 mm width footprint. Ambient operating range is -25 to +60 °C, and the front face carries IP20 finger protection.
What the ratings mean for fit
The AC-2 rating of 4 kW at 400 V governs motor duty for wound-rotor or slip-ring motors — this is the rating that decides real-world fit, not the higher AC-1 or AC-12 numbers. For resistive or lightly inductive loads, the 10 A AC-12 rating applies. The 4 NO main contact arrangement is unusual — most size S00 contactors carry 3 NO + 1 NC; this one has no NC main contacts, so if your circuit requires a normally-closed main pole, this is not the right variant. Short-circuit coordination: with type 2 coordination, a 20 A gL/gG fuse limits let-through energy; type 1 allows up to 35 A gL/gG. The coil draws 3.3 W DC both on pickup and hold — no economizer dropout to worry about.
Wiring and terminal specs
Main circuit terminals accept solid or stranded: 2x 0.5–1.5 mm², 2x 0.75–2.5 mm², or max 2x 0.75–4 mm². AWG equivalents: 2x 20–16, 2x 18–14, or 1x 12. Finely stranded with ferrule: same cross-sections. Side clearance of 6 mm is required for heat dissipation when mounting side-by-side — no additional gap needed if ambient stays within rating.