And yes Cooper, that's my question exactly. This went from a nasty arc to a devestaing fire. Isn't the job of an overcurrent device specifically to avoid fires and protect the installation? This is obviously a massive failure all the way around.
Any linemen in here know why this happened, and what was supposed to happen when the line fell?
Service conductors essentially have no overcurrent protection. On my street we have 3 transformers feeding a 120/240 "bus" that serves about 10 houses. If overall demand is low you could see virtually all of that power in one SE fault. I doubt you could ever blow a primary fuse.
As spectacular as that arc fire looked, the fact that it was continuing to arc instead of blowing up was indicative of it being a high resistance ground fault. That would explain why the SCPD did not clear it; it wasn't pulling sufficient current to blow the fuses or trip the breaker. That video makes a great argument for arcing ground fault detection devices.