Not me personally, but I was training (and
supposed to be supervising) a new tech on installing a new Motorola mobile radio in the trunk of a brand new police car. Note our shop had an indoor garage just for installing and troubleshooting radios in emergency response vehicles.
I pointed out the ideal location for the 4 mounting holes on the trunk floor, ensured he had the right size drill bit and had the template sitting right, then went back to my bench while he drilled the holes and mounted the mounting bracket. We then went on to run the harness, control head, antenna, etc. Tested the system, and turned it back over to the PD motor pool.
Two days later, we got a call from the PD motor pool chief. It seems on the next patrol shift, they filled the car with fuel and immediately started to smell gas fumes, big time in the car and quickly returned it to motor pool. Their mechanics inspected the fuel system, pump, filler tube, and fuel lines - all good. So they ended up dropping the fuel tank where they immediately discovered 4 holes drilled into the tank that exactly matched the 4 holes in the trunk floor!
It seems my trainee drilled through the trunk floor just fine, but kept going and hit resistance when hitting the fuel tank top. Note the tank was located a good inch below the trunk bottom. But instead of stopping after going through the trunk floor, he kept on drilling until he drilled through the top of the tank too - then did that 3 more times.
Note the radio's mounting bracket screws, which he had with him, where just 1/2 inch long.
Why a spark from the drill didn't blow up the car, our shop, and everyone around, I don't know. Someone was watching over us that day. So my stupidity for assuming my trainee would know to stop drilling after he poked through the trunk floor. That never happened again.
***
For me personally, I was about 8 or 9 years old and already interested in electronics. I found an old radio somewhere that looked like it had been dropped more than once. But I wanted to see if it still worked. So I plugged it in, played with the knobs, slapped it around a bit and, no. It was dead.
I decided it was not worth keeping and to just throw it away. But first, I wanted to keep the power cord because... well... "
I might need it someday!"
I went and got one of my dad's
dikes and snipped the cord. That is when I quickly discovered I forgot the other end of the cord was still plugged into the wall. Lucky for me, I squeezed hard and fast to cut the cord so the circuit opened
nearly as quick as the
short I created. A valuable lesson learned I still vividly recall to this day
every time I'm about to cut a wire, to ensure I am not about to make the same stupid mistake.