An electrical system (1) for a three-phase alternating current network, comprising a transformer (20U, 20V, 20W) with a primary side (30U, 30V, 30W) and a secondary side for each phase (U, V, W) of the alternating current network; a separate transformer housing (60U, 60V, 60W) for each transformer (20U . . . W); and a switching assembly (100) connected to the transformers (20U . . . W); wherein the primary side (30U . . . W) and/or the secondary side has a main winding (21, 22, 23) and a regulating winding (31, 32, 33) in each phase; the switching assembly (100) is designed such that it can connect each regulating winding (31, 32, 33) with each of the main windings (21, 22, 23); and the switching assembly (100) is arranged in one of the transformer housings (60U . . . W) or in an own switch housing (70).