The breaker and bus had leaked out so much smoke that they actually melted and quit working. See, it's the conductor that carries the smoke from one device to another. It starts at a power plant where the stuff is burned to produce smoke. The smoke we see coming from the stacks is excess that the system doesn't need. The smoke is then sent down the conductors to transformers.
Transformers are big and require lots of smoke to work properly.
That's why the conductors are so big.