Proper labeling, sad to say a lot don't. Annealled 16 AWG, NEVER trust 18 AWG on mining.
My mining career has only been 8 going on 9 months. I built up to the point of needing server psu's and these came with it.
Thankfully my only issue was with a faulty v007 riser.
Beware AWG 18's on especially new gpus, voltage ratings are on best case scenario and they will begin to malform based on heat alone.