A transformer includes an outer cabinet and an inner tank. The outer cabinet includes a base configured to be installed below ground level, a housing wall configured to be installed at least partially below ground level, and a sill coupled to the housing wall and configured to be installed above ground level. The sill includes a top access opening between an interior space of the outer cabinet and an exterior of the outer cabinet. The inner tank is disposed on the base at least partially below ground level and includes an active part including a transformer circuit. The inner tank includes a plurality of terminals electrically coupled to the active part, each terminal extending from the inner tank into the interior space of the outer cabinet along a respective terminal axis that passes through the top access opening at a respective upward angle with respect to ground level.