400.22 Grounded-Conductor Identification(C) ... For jacketed cords furnished with appliances, one conductor having its insulation colored light blue, with the other conductors having their insulation of a readily distinguishable color other than white or gray.
I see blue and yellow 120v circuits in many non-permit pipe jobs. My guess is Europians doing the work and no one told them we use white and grey. No one told them you shouldn't put #14's on a 30a breaker.
We're in for a lot of confusion with the new adoption of European colors here as well. Just look at some of threads where we've discussed this in the non-U.S. area.
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No one told them you shouldn't put #14's on a 30a breaker.
That's part of the hidden "in wall" electric heating system!