When wiring face plates for a ring main with 2.5mm wire is it advisable, sensible or unnecessary to double over the wire where it gets tightened to the connections?

 

I ask because I seem to remember my previous electrician saying he always liked to double over any wires up to and including 2.5mm to provide a better contact.

My current electrician isn't doing that so I am wondering if I should ask him to.

 

Any thoughts?

If I've one or two 2.5s going into a face plate terminal I double them up. If 3 I tend to leave them as they are.

 

I strip back nom 18mm and bend over to 9mm. 

 

Not all terminals mind are made equal in terms of size i.e amount you can get in. Ditto the quality of terminal and how likely they are to strip or have the head shear off!