My colleague and I were at the Ryvita Plant in Poole, installing an American made Mass flow meter.
The design of the power supply part of the PCB was such that it was as easy as anything to short the L and N terminals (not so easy in the UK manufactured version) and that, inadvertently, was what we then did.
There is nothing so embarrassing as the sudden hush of an entire factory shutting down as various mains breakers tripped out and the silence then filled next with the sound of rushing feet heading our way as the plant manager came to see what had shut-down his plant.
The next day when we arrived we found their electrician had been busy and installed our own personal circuit breaker so that if we repeated our misadventure only our bit of kit would be affected.
Mistakes in the home environment are far less embarrassing.
Incidentally, Ryvita is a healthy diet option.... but my colleague (from Manchester) was impressed by the works canteen (something that appears to be disappearing from the British working scene) where breakfast was all things cooked in deep fat fryers.... including black pudding, sausages, bacon, mushrooms etc. The sight of all these staples swimming in fat was almost too much for him.