EN60204-1:2006; +24VDC and -24VDC Wire Colours

Hello All


I have a piece of equipment that I am trying to wire up in accordance to EN60204-1:2006.


On the equipment I have AC mains (230VAC) coming in, this is then converted to +/-24VDC


According to the attached document, for AC and DC power circuits the wire colour black is used, so does this mean for my +/-24VDC, I use black for both the positive and negative?


This is strange as you would not be able to tell the difference between +24VDC and -24VDC


Could someone please clarify


Many thanks in advance