

Yeah my assumption would be that it was open on both sides, otherwise it wouldn’t be deenergized. But that doesn’t mean you can’t get induced current flow. Let’s say our dead line shares a tower with a high voltage live line. Our dead line has multiple ground connections via undergrowth. The live line experiences a line to ground fault, creating high currents in its faulted phase but also a ground potential rise at the fault location. So now our dead line is experiencing possible potential differences between its many ground locations as well as induced current. This current would be inherently directed to the lower potential ground which in this case is likely via a tree branch. I don’t think it would take much current or much time for that to create a fire.
Again, I don’t think any of this is particularly likely, but I don’t think it’s out of the question either. At the very least it’s the kind of question industry should always be asking itself
If destruction be our lot, we ourselves must be it’s author and finisher