Had the guys who came in to clean a carpet do that, despite the red colour of the socket, the label on it, the fact they had to use a hammer to put the plug into the polarised socket ( breaking it in the process), and the regular AC power socket right next to it. Not good for the UPS to get an extra 20A load from the carpet cleaner, it tripped out and all the computers including the server went dead. The trip probably was the cause for the one power supply in the server dying a week later. At least I am good at cold starting the network...... Good thing as well I use only 5A breakers on all the UPS feeds, as they trip showing where to look for who plugged something in.