I designed this in Tinkercad with my limited skills…. it is for a 2x12 12v terminal block that I am using to distribute power to LED strip lights on a 3x4 Ikea Kallax shelf. Uses 2x M3x6 threaded inserts and 2x M3x16 screws… Its not a perfect design but works for the intended purpose of covering most of the terminal block.

things to note:

the bottom plate is thin and the heat inserts may bulge a tiny bit

the clearance on the narrow side is minimal, so the soldering iron may touch the wall when pushing the inserts into the hole

the screws dont really hold down the terminal block, only the lid… the so the block may rattle a slight bit… can be solved by an M3 nut or by adding standoff posts to the lid.