I was trying to test a transformer with a bro-physics(tm) technique.
Basically, we connected a 120V to 24V transformer to the mains. with one cable we tested the voltage of the mains (which is typically 127Vrms in Mexico), with the other we would be testing the output of the transformer.
We supposed that by connecting the oscilloscope leads directly to both ends of the transformer we would get a good idea of how well it was actually doing it’s job. Since the transformers we get tend to be pretty bad; some were going from 120 to 40 or 50, and we wanted to be sure it was doing it’s job properly.
Instead, it exploded almost immediately after we turned on the mains . While I have no clue what happened, I suspect we tried to throw too much current at the oscilloscope and it murdered the cable in self defense. It was quite spectacular actually; though it exploding directly in front of my lab partner’s face is not ideal.