Mix of old and new colours for singles for same circuit

[timhoward]

New one for me...
Commercial building (museum), 3 phase board
16A MCB, 3 x 2.5mm singles run in 20mm conduit, ending up at an FCU. All fine.
The singles are red, blue, and yellow/green.
Red is used for L1, Blue is used for N

My gut reaction is that this is just too confusing and needs sorting.
Tiny niggling doubt is that technically each wire is a permitted colour for it's use. I can't see anything in regs about consistency of old/new colours on the same circuit.
Any thoughts one way or the other? I'm leaning heavily on "this is not ok" regs or not.

 

[pc1966]

That would trouble me. Taken as a pair it is wrong by both standards, so I would personally say they should be sleeved at both ends in some consistent manner (realistically brown and blue sleeving so it is clearer that the blue really is neutral in new colours).

 

[ImpededLoop]

In the old days (pre 2004) it was common to find single phase circuits wired in SWA with red as line, yellow as cpc and blue as neutral. The fact its singles in conduit makes no real difference. As has been said, sleeve the red as brown or the blue to black and all is good.

 

[timhoward]

I don’t know why sleeving didn’t cross my mind! Thanks all