A stator for an electrical machine has a stator core (16) with stator grooves (19). Stator windings (17) are received in the stator grooves (19) of the stator core (16). Groove insulators (20) are received in the stator grooves (19) of the stator core (16) such that the groove insulators (20) are arranged between the stator core (16) and the stator windings (17). The groove insulators (20) are made of plastic, namely a first plastic that provides the isolation function of the groove insulator (20) and a second plastic and/or a third plastic that provides a function of the respective groove insulator (20) differing from the isolating function.