system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why do Power Transformers explode?
gpt
Power transformers run at fairly high voltages. The voltage is so high it can actually throw lightning around inside, so they put oil inside the box to keep the electricity going where it needs to, since oil can hold back higher voltages before it throws lightning. 

Unfortunately, in some worst case scenarios, the oil can't hold back all of the voltage, so it gets ignited by the lightning in the box. Then it builds up pressure that the box can't hold. In the end you get a giant fireball, and lots of people lose power.