Voltage indication device (2), attachable to a medium-voltage separable plug having a rear insert comprising a coupling electrode. The voltage indication device comprises a body (241) and a voltage detector (251) having a ground contact (361), a voltage contact (261) for electrical connection to the coupling electrode; and an indicator for visually indicating presence of the medium voltage in the separable plug. The body comprises an elastically expandable support portion (406) for resiliently supporting the voltage detector (251).