A connecting device for electrically connecting a three-phase motor having three windings (U, V, W) to a three-phase network. The connecting device comprises a mains connection unit (18; 68) for connecting the phase lines (L1, L2, L3) of the three-phase network, and a motor connection unit (14; 110) for connecting the six winding ends (U1, U2, V1, V2, W1, W2) of the three-phase motor. An exchangeable coupling module (16; 70, 72; 70, 72′) is furthermore provided, which is arranged between the mains connection unit and the motor connection unit and contains contacts and wiring elements electrically connecting the six winding ends (U1, U2, V1, V2, W1, W2) in a predefined manner to the three phase lines (L1, L2, L3) of the three-phase network.