EN 50216-4 specifies basic accessories of transformers, such as thermometer pockets, to be used for liquid immersed transformers, earth terminals; to be used for liquid immersed and dry-type transformers, draining plugs, to be used for liquid immersed distribution transformers, filling openings, to be used for liquid immersed distribution transformers, wheel assembly, choice and distance between centres, to be used for liquid immersed and dry-type distribution transformers.