In theory, it would be Good Practice to have a system in place that sees mains cables regularly (define "regularly"!) examined for condition, and tested for electrical safety and integrity (insulation, continuity).
However (and as we have seen), this only makes sense if such tests can be documented, which also means that the cables need to be readily indentifiable. That way results can be recorded on our favourite database, spreadsheet, log-book etc.
But how to do this? And how to do it without spending (wasting) endless man-hours that most likely would have been more gainfully expended elsewhere?
We have seen mention of:-
1) Colour-coded cables
2) Individual labelling
I have given this aspect (labelling, recording) a fair amount of thought, and have yet to come up with anything definitive; other than, if you have the resources to tag and record, then by all means do it - but (on the other hand) if you don't, then concentrate instead on the "quality assurance" measures
outlined in the above post.
And, if pressed by Senior Management or Quality Audit Inspectors (or whomever), simply issue a blanket statement along the lines of "a rolling programme of examination and testing of all detachable mains cables is in place"!