Smart plug for server to diagnose problem

[benjii]

My server is rebooting randomly. It can be days or even over a month between reboots. The logs are completely clean. This leads me to believe the problem is either hardware (motherboard or PSU) or the power supply to the server.

Are there smart plugs out there that are accurate enough, with logging, to tell if the power draw from the wall has any wild, but brief, fluctuations?

 

[benjii]

You'll see power, current and volts logged. I can't imagine it'll be of massive use though, you'll probably just see a sudden drop when it reboots which isn't really going to tell you much.

Are they not accurate enough to tell which side drops first? The wall socket or the PSU?