Buried distribution type transformers

This paper describes the preliminary tests, design, and insulation of distribution transformers located underground, instead of overhead on poles, and in direct contact with the earth, in contrast with those located in expensive underground vaults. The preliminary tests indicating the feasibility of such a method of installation are outlined. The special transformer case used, including such details as the water and air-tight inner cover with pressure seal, is described. Buried oil cut-outs of special type where required are also described. The ease of replacing defective transformer coils is also indicated.