An electrical device for connecting to a high-voltage power grid has a boiler, which is filled with an insulating fluid and in which a magnetizable core and at least one winding, which surrounds a section of the core, are arranged, and a cooling system which includes at least one radiator which is arranged outside the boiler and is connected thereto via the radiator in order to circulate the insulating fluid, wherein the radiator has at least two heat exchange elements which are connected in parallel with one another. In order to enable a cold start to be accelerated and to be carried out even at relatively low temperatures only one of the heat exchange elements has a heat-conducting connection, as a heated heat exchange element, to a heat source which generates heat when the operation of the electrical device is started.