davezawadi (David Stone): 
 

The Earth colour is not G/Y because that throws up all kinds of moulding difficulties, and means a complex second set of expensive dies and a double (2 shot) moulding machine. It doesn't matter does it and this is not cable insulation so out of scope for BS7671?

It's not out of scope for BS EN 60445 though, which in this case aligns with BS 7671 … 

I am much more concerned that wires are not tightly fixed as I said above.

Agreed, that is concerning. I've not seen this with properly fitted screwless connectors I've used … but I've not had hands-on with this particular product.

You need to study creep somewhat Graham, it is not a normal temperature phenomenon in copper, only perhaps if the wire gets very hot (hundreds of degrees), and usually work hardening will limit any small change due to the screw pressure (which is very high hopefully). 

I'm happy with experience which tells me, better than trying to break down the particular element of theory in play, that screw terminals for copper conductors need tightening after a few years, regardless of whether they were tightened properly in the first place. Yes, copper has a much better resistance to creep than aluminium, but I know it still happens. It might not actually be “creep” proper, but other mechanical stresses coming to play all at the same time, and the fact that the copper is not evenly stressed - I say that because properly made crimp connections seem to fare far better.

davezawadi (David Stone): 
 

The Earth colour is not G/Y because that throws up all kinds of moulding difficulties, and means a complex second set of expensive dies and a double (2 shot) moulding machine. It doesn't matter does it and this is not cable insulation so out of scope for BS7671?

It's not out of scope for BS EN 60445 though, which in this case aligns with BS 7671 … 

I am much more concerned that wires are not tightly fixed as I said above.

Agreed, that is concerning. I've not seen this with properly fitted screwless connectors I've used … but I've not had hands-on with this particular product.

You need to study creep somewhat Graham, it is not a normal temperature phenomenon in copper, only perhaps if the wire gets very hot (hundreds of degrees), and usually work hardening will limit any small change due to the screw pressure (which is very high hopefully). 

I'm happy with experience which tells me, better than trying to break down the particular element of theory in play, that screw terminals for copper conductors need tightening after a few years, regardless of whether they were tightened properly in the first place. Yes, copper has a much better resistance to creep than aluminium, but I know it still happens. It might not actually be “creep” proper, but other mechanical stresses coming to play all at the same time, and the fact that the copper is not evenly stressed - I say that because properly made crimp connections seem to fare far better.