You should not be using brown & grey in a panel anyway for phase conductors really, as these colours are not recognised in 60204.
From 60204
13.2.4 Identification by colour
Where colour-coding is used for identification of conductors (other than the protective
conductor (see 13.2.2) and the neutral conductor (see 13.2.3)), the following colours may be
used:
BLACK, BROWN, RED, ORANGE, YELLOW, GREEN, BLUE (including LIGHT BLUE),
VIOLET, GREY, WHITE, PINK, TURQUOISE.
NOTE This list of colours is derived from IEC 60757.
I was thinking more about this section!
Where colour-coding is used for identification of conductors, it is recommended that they be
colour-coded as follows:
– BLACK: a.c. and d.c. power circuits;
– RED: a.c. control circuits;
– BLUE: d.c. control circuits;
– ORANGE: excepted circuits in accordance with 5.3.5.
Exceptions: to the above are permitted where:
– insulation is used that is not available in the colours recommended; or
– multiconductor cable is used, but not the bicolour combination GREEN-AND-YELLOW.