Almost PBC!
Red is a.c. control
Black is a.c. power
As per BS EN 60204-1.
Oh and fair cop appropriate sleeving would be OK.
It was getting late & I left out a bit, in that sleeved brown, black, grey & blue would not be compliant with 60204 as these colours are not recognised IIRC, my copy is not around now.
I just posted this as a thought provoker as 7671 is not the only standard relevant to electrical systems.
In fact 60204 does have as much if not more clout as it is a harmonised standard which is stated in the Machinery Directive as a way of compliance with its EHSR's.
BTW, I still have some B&R fixed install wiring mtls and would use them up if it were necessary, and just add a comment on the MWC/EIC that both colours are in use, and yes I would over mark them with the new colours, I do this with any old colours I come across as well as adding "the sticker" where relevant, normally I do the true origin & the circuit origin DB at which I work.
Paul