This is a common fuse hardware. Every transformator poles have 3 pieces from it. It is the most common type. The newer types are alike, but they use plastic Insulators. This fuse is 16 A, 20 kV, The Insulators are noname. We hunted it at two days ago. Every transformer has a 3 phase switch on the last pole, the transformer pole has the varistor (high voltage protection), fuse and the 3 phase oil transformer. The European norm write: everywhere must be the 3 phases.

[IFONA]