Did naval gun foundries generate their own power?

Did heavy-gun foundries maintain independent power supplies to protect production from an external outage?

Yes. Their enormous heat and power demands encouraged vertically integrated works that generated their own power and handled much of their own supporting infrastructure.

A naval gun factory was closer to an industrial complex than a single machining shop. Forging and finishing very large weapons required sustained energy, heavy material handling, and reliable internal services. These works often produced their own power and connected directly to railways carrying coal and other inputs. Battleship armament depended on the industrial and transport systems that made large-caliber production possible.