22-03-2025, 05:50 PM
It looks like a sub grid switching frame so its likely to be an oil filled switch that ignited. I used to help build supergrid transformers at Ferranti's many many moons ago, transformer oil is insipid, it has a low vapour flash point, OK as long as its contained, but as they discovered, let it loose and it will flare up.
Boater Sam.
