An electrical machine is provided comprising at least one random wound coil (10) out of a winding wire (1) comprising a conductor (2), and an insulation layer (3) surrounding the conductor (2) along a longitudinal direction thereof. The winding wire (1) comprises a conductive layer (4) surrounding the insulation layer (3) along a longitudinal direction thereof. Due to the conductive layer (4) the coil is grounded and partial discharges and bearing currents are reduced.