Actually somewhat typical for tight bends, I expect to see it. Some of what you'd be showing is thinning of insulation on the back of the bend, which always affects photo-infrared viewers showing as hot spots. It is also typical for some strands to be damaged by extremely tight bends because of the methods used to obtain them.
Is your cable in fact correctly sized (to obtain a lower operating temperature)? I'm doubtful. What factors were used in determining it's size? Remember that cable sizing is based to some degree on conductor temperature, which is why higher temperature rated insulation on cables show higher ampacity on sizing tables.
Running load amperes should be measured and compared to ampacity charts for the size (circular mils or gage). This is a simple way to determine the expected operating temperature for the wiring. Especially if you have moderate to extended startup time, the additional heating from that additional startup current will not just disappear when the current drops. Time between startups and unloaded time are all factors.
You also mention small space in the "cubicle". This is also another factor which contributes to higher temperatures. Is the MCC placed for good ventilation and cooling? Do the cables run high in the MCC? Heat from all other cabling, thermal units in other starters, transformers, VS drives,etc will contribute and rise to the top of the MCC.
LOTS of considerations. 50' C isn't very hot at all in my experience. Perhaps it ought to be, but it's not likely with all efforts being put into minimizing costs particularly as opposed to heating.
flash
Me wrong? I'm just fine-tuning my sarcasm!
