SIRIUS S0 power contactor — 4-pole NO, 11 kW at AC-2 400 V
The Siemens SIRIUS 3RT1326-1AC20 is a size S0 power contactor with four normally open main contacts, rated for 11 kW at AC-2 duty at 400 V. Rated operational current at 24 V is 10 A, dropping to 6 A at 230 V and 3 A at 400 V. The contactor handles AC-2 motor loads up to 11 kW at 400 V, which covers most squirrel-cage induction motors in that power band. For type 2 coordination, the required fuse is gL/gG 35 A; type 1 coordination allows up to 63 A gL/gG.
Mounting and wiring integration
Dimensions are 85 mm height, 61 mm width, and 91 mm depth. The 61 mm width is the S0 frame standard, so it occupies one 18 mm module position on a DIN rail. Main circuit terminals are screw-type, accepting solid conductors from 2x (0.5 to 1.5 mm²) up to 2x (0.75 to 4 mm²), and stranded from 2x (1 to 2.5 mm²) up to 2x 10 mm². AWG equivalents are 2x (20 to 16) solid and 2x (18 to 14) stranded, with a maximum 1x 12 AWG. The auxiliary contact block terminals accept 2x (0.5 to 1.5 mm²) solid and 2x (0.75 to 2.5 mm²) stranded, max 2x (0.75 to 4 mm²). Strip length should follow standard practice for screw terminals — typically 8 to 10 mm for the main terminals.