HTT resin-encapsulated transformers are mechanically and thermally stable in terms of changing load, short-circuits and extreme climatic conditions. They are produced in accordance with Climatic Classification C2, Environmental Classification E2 and Fire Classification F1. The winding material consists of copper, the HV and LV coils are cast under vacuum. Thanks to the extremely flexible casting moulds the transformers can be adapted to a high extent to the room facilities on site. For the transport (here into a pit) extreme positions are possible.