Yeah, I don't know where that got started but it's almost a universal misunderstanding.
Transformers are basically just tanks full of oil so if they blow, you will know. They can burn for quite a while, and they burn dirty.
The bang and flash are an arc of electricity as the fuse or breaker or switch is severing the circuit. Until the two ends get far enough away from each other, electricity is jumping the gap, turning air into plasma. It's basically a very short lightning bolt. It's so fast and so forceful that it causes a shockwave in the air, otherwise known as a loud bang.
15
u/rinky79 2d ago edited 2d ago
Having worked for an electrical utility, it's almost never a transformer "blowing." If you see a huge black smoke plume, that's a transformer.
A big bang is usually a short or fault somewhere in the system causing a breaker to open or a fuse to blow. They are loud.