LLigetfa
DIYer, not in the trades
On one of the systems I setup, the generator was running really rough and as a result the UPS kept rejecting it which dumped the load, then the generator would smooth out and the UPS would accept it but immediately run rough and reject it again. I called the mechanic to change the spark plugs on it (the Briggs and Stratton engine ate plugs like crazy). The mechanic not wanting to believe me that it was the plugs started fiddling around with it and took it to wide open throttle. The UPS did not take kindly to that and got damaged. It did not take out any servers or networking equipment despite damage to the inverter but on my office outlets that were wired to the UPS, I could no longer use a battery charger powered by that UPS.