These are terminal blocks for transformers, assembled with 8 poles together, featuring 20A type (TEV158) and 40A type (TEV308).
(The image is TEV158.)
Regarding the specifications not listed in the below chart, please check them at: KASUGA Terminal Block Product Search. Datasheets can be referred to from the retrieval page and CAD files can also be downloaded from the link in the result page.