The beauty about the tunnel terminals used on the newer outlets is the ability to fit up to four 2.5mm2 wires into one terminal. Older outlets could take maybe 2 2.5mm2 wires easily.
As seen in my travels the other day, an outlet for a pump around 50 metres from the board was done in 6mm2 wire, the outlet took this wire with no problems which may be a task on an outlet with screw terminals (I'll try it later, I have some 6mm2 offcuts and some "CIRCLE F" 125V 15A switched outlets in the shed, let you all know how I get on with this experiment)
The 6/32 screws are still in use here to mount outlets, some people try to use M3.5 with not too much luck...
The colour coding for the screw tunnels is red for Active, Green for Earth and the nuetral has no colour coding ( most, if not all outlet mechanisms are black in colour). This is done with small coloured dots or more recently as ink applied to the entrance to the cable tunnels.
The 84mm mounting centres do match the American spacings to witin a millimetre sometimes closer. In my shed I have Circle F brand outlets mounted onto Clipsal mounting blocks.
