That admittedly was kind of my thought at the time. As he explained to me, often the underground cable will short out due to water ingress (it had rained a lot in the previous few hours), and pumping 300+A through that water could often drive the water off, and resolve the short.

It took a bit of persuading to get him to believe me about the smell of burning plastic and suspiciously dry area of pavement just down the road. Once he believed me, a crew came in, dug the thing up, replaced a section of cable, and relaid tarmac, in a surprisingly short time.