I recently experienced the error "RAC0182 The iDRAC firmware was rebooted with the following reason: AC" that forced three out of four nodes on my PE servers to reboot at the same time. During the time this error occurred, no one was anywhere near the PE server. I found a similar article on dell support https://www.dell.com/support/article/id/en/idbsd1/sln309655/dell-poweredge-idrac9-rac0182-the-idrac-firmware-was-rebooted?lang=en

However, the problem mentioned in this article was for watchdogs while my problem was AC. In addition my iDRAC firmware version is well above the version mentioned in the article when this particular incident occurred. I am struggling to find out what caused this event to happening.