A portable device has an electric motor connected to a housing with a female electrical socket, an electrical power cable with a male plug and an electrical safety device. The safety device has a first element borne by the male plug and a second element located within the housing. The second element has a locking element to lock an activation element for activating the motor in a deactivated position. The first element of the male plug is configured to engage with the locking element to free the activation element to activate the motor.