AJJewsbury: 
 

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.

Some DIN rail earth terminals look like they've been single-shot moulded using a mix of yellow and green plastic - result is more of a smear of blotches rather than any kind of neat stripe and to my mind they look absolutely terrible - but presumably comply with standards.. Give me a plain colour and use symbol marking to identify the terminals any day.

   - Andy.

plain yellow would be permissible on this premise in BS 7671, but not in BS EN 60445.

What BS EN 60445 actually says is “The single colours GREEN and YELLOW are only permitted where confusion with the colouring of the conductors in accordance with 6.3.2 to 6.3.6 is not likely to occur.” 

Which is another way of saying what BS 7671 says regarding green alone.

In this case, there is clearly confusion as green is used for the function.

Colours may be applied to terminals or conductors for identification according to BS EN 60445 (Table A.1 of that standard).

I perfectly agree that the earth terminal is marked with the graphical symbol  for protective conductor, but the terminal is also identified incorrectly as “E” not “PE” on some products: BS 1363-2 only specifies the graphical symbol, so I don't know where “E” comes from.

AJJewsbury: 
 

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.

Some DIN rail earth terminals look like they've been single-shot moulded using a mix of yellow and green plastic - result is more of a smear of blotches rather than any kind of neat stripe and to my mind they look absolutely terrible - but presumably comply with standards.. Give me a plain colour and use symbol marking to identify the terminals any day.

   - Andy.

plain yellow would be permissible on this premise in BS 7671, but not in BS EN 60445.

What BS EN 60445 actually says is “The single colours GREEN and YELLOW are only permitted where confusion with the colouring of the conductors in accordance with 6.3.2 to 6.3.6 is not likely to occur.” 

Which is another way of saying what BS 7671 says regarding green alone.

In this case, there is clearly confusion as green is used for the function.

Colours may be applied to terminals or conductors for identification according to BS EN 60445 (Table A.1 of that standard).

I perfectly agree that the earth terminal is marked with the graphical symbol  for protective conductor, but the terminal is also identified incorrectly as “E” not “PE” on some products: BS 1363-2 only specifies the graphical symbol, so I don't know where “E” comes from.