Why is my mac shutting down at random?

Recently my MAC began shutting down completely. This happens at random while on or off of the charger. I have ran system checks on my hard drives and verified them etc. I have checked to see what my battery health is. I have a late model 2010 MAC. Battery cycles are at 520 and says condition is normal.

I have upgraded to Yosemite 10.10.2.

I have searched these forums and cannot identify my issue. This is my final attempt to resolve this issue and If I cannot I will have to take it to apple and allow them to find/fix the issue.