[einpoklum]

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/

[fgfarben]

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.

[einpoklum]

I wonder if crushing is more of a phenomenon when you have a lever you're encouraged to push down to a flush position, rather than a screw you tighten and have tactile feedback regarding the difficult of tightening further.

[orangewindies]

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.

[einpoklum]

I guess that's theoretically possible, but - I've not known this to happen anywhere in my lifetime, and I've not seem use of ferrules in wire terminals anywhere.