I have a question about those wire ferrules they said they were using:
I occasionally connect wires to terminals, but - I've never used ferrules: I just self-twist the thin strands, push the thing in, and use the lever or tightening screw depending on the terminal's mechanism.
Why would I use a ferrule? Or perhaps, under what circumstances is that advised?
PS - Link to the ferrules they mentioned: https://www.amazon.com/gp/product/B07R6QQ7MW/
The wire will crush over time and the connection will become looser. That will increase the resistance of the connection and in high current applications will cause heating. If you're really unlucky it will cause a fire.
Ferrules often have insulating shells around the base which are good strain relief.
Ferrules also evenly distribute the clamping force and prevent crushing of the strands.
Ferrules solve the problem of having to align the threads every time you re-post them in a terminal block.