An electrical apparatus having a cooling system includes a first cover to cover a first part of the electrical apparatus to be cooled and a second cover substantially enclosing the first cover to define a surrounding space. A base plate on which the first cover is mounted defines an environmentally-sealed enclosure that houses the first part of electrical apparatus. A first circulation device causes air to circulate in the environmentally-sealed enclosure and a second circulation device causes a cooling fluid to circulate around the surrounding space. A heat transfer structure is positioned on each side of the first cover. A third cover is mounted to an opposite side of the base plate from the first cover to define a second enclosure that houses a second part of the electrical apparatus to be cooled. A heat exchange structure is positioned within the second enclosure. The second circulation device is arranged to drive cooling fluid both through the heat exchange structure and through the surrounding space.