I have an Acer VN7-791g that will randomly shut down anywhere from 5 minutes to an hour. I've tested everything I can think of and think I may have a bad motherboard at this point. I've reinstalled windows, replaced ram and hard drive. It does this with or without the charger connected. I dont believe its heat related, it will shut down when sitting on the desktop. I've also ran cpu and gpu benchmarks and the cpu temp will spike to around 93c but doesnt shut down. I dont get any windows errors or logs, the computer just instantly powers off to a black screen. Event viewer just shows an unexpected shut down.
If it is getting to 93 and you aren't say doing some serious gaming at the time, then it is overheating. You didn't say which is getting to that temp, but that is high for anything that isn't really using the system like gaming. If that is the case, while it may not shut down immediately, it is likely causing issues that will cause it to turn of. Damage to the GPU/CPU/Motherboard, etc., will cause this.
I would suggest having it looked at. Either by the manufacturer, if it under warranty, or by a local tech if it isn't.
The cpu will spike to around 93 when running a stress test in CPU-Z. Normally it's sitting around 40-50C. I think I will try some new thermal paste. The laptop is probably 4-5 years old so it wouldn't hurt to reapply. Maybe some other component is overheating, possible the VRMs? It does seem like either power delivery or something is getting too hot. If the thermal paste doesn't help then the laptop will just be scrapped for parts. A used motherboard is $300+ so not worth replacing.
I would definitely get some monitoring software (there are lots of free ones) and see what is what temperature wise. Just remember it might take a few trial and error installs with the different software. Not all of them work with all laptops.