[Thread resurrection]
I have previously been an advocate of crimping mains cables, both solid and stranded, provided the correct tool is used. Now I need to add to that.
Do NOT trust the insulated crimps from unknown manufacturers, as supplied by many otherwise excellent electrical wholesalers until you have taken one from the pack, and snipped off the plastic to see that it is adequate (preferably after purchase ). I found some today that had an excessive amount of the metal in the middle section removed, by my guesstimation, down to maybe 2.0 sq mm, or maybe less, and very soft squishy copper at that. Being that these crimps are rated for 12 AWG wire which is around 3.06 sq mm CSA, I consider this a dangerous defect.
Fortunately I was warned by the fact that my Amp crimp tool just crimped them as if they were mere plastic, indeed, one broke in the middle, with the plastic holding the broken parts in place.
A severe potential fire risk there, that would not have been caused by the usual suspects with crimps [poor crimping] but by what I consider to be a manufacturing defect.
Suffice to say, strip connector got used instead, thank $DEITY I found it before energizing the 32 amp circuit they were on.
Hope this forewarns someone and saves someone losing everything.