My wife and family are spending the week on the Outer Banks. The other (southern) end of the barrier island has been evacuated due to a power outage.
A crew building (repairing?) a bridge sunk a piling in exactly the wrong spot, cutting power. Nobody was hurt.
Just as a visual, would there have some earth-shattering kaboom? A flash of lightening or nothing at all?
I suppose we were lucky nobody was hurt. Would such an event be as dangerous as it sounds?
Poking around on google, a lot of articles are calling it a transmission line. However, another reference I found related to power and the Outer Banks said that all transmission lines were overhead, but said that there are several hundred miles of underground distribution lines in that area. Most reporters and people who don’t real with power systems aren’t going to understand the difference between a transmission line and a distribution line, so I can’t really fault the reporting too much for that. It does make it difficult for me to tell exactly what happened, though.
Transmission lines carry power from one area to another. They typically run at very high voltages, commonly in the 50 to 150 thousand volt range, though some are a lot higher than that. The transmission line will end at a substation, and from there, distribution lines will carry the power out to the surrounding area.
Distribution lines are much lower in voltage, typically somewhere between 3,000 and 10,000 volts, though many of the newer ones go up to about 20,000 volts or so (and some a bit higher).
Transmission lines are almost always overhead, and the wires are not insulated. Distribution lines are commonly overhead, but many are buried. The overhead wires may or may not be insulated. Small transformers attached to distribution lines typically will feed three or four homes per transformer. In overhead distribution systems, the transformer will be on the pole. In underground distribution systems, the transformer will be in a large box on the ground.
Pole mounted transformer:
Transformer for underground lines:
https://www.pacificpower.net/content/dam/pacific_power/image/Contractors_and_Suppliers/Line_Ext_Estimator/t2.jpg
I’m guessing that they took out a fairly high voltage distribution line.
Either way, whether they hit an underground transmission line or a distribution line, there definitely would have been a big flash and, if you were reasonably close to it, it certainly would have been an earth-shattering kaboom.
Most of the faults in this video are overhead, but it should give you an idea of the amount of power involved.
Here’s another video to give you an idea of the power involved:
If they were driving a piling at the time, chances are the fault was underground and under water, so from the surface you wouldn’t have seen much.
Sometimes there’s one big kaboom, and sometimes it’s more of a long, drawn-out affair with lots of arcing and excitement.
It is every bit as dangerous as it sounds, and then some.
Sadly, the timing of the event was awful. It’s the middle of their high season, and they’ve had to evacuate all tourists from Ocracoke Island, which, of course, is accessible solely by ferry. 
I have great interest in the goings on on Hatteras Island. My vacations the last 20+ years are in Avon NC. I’ll be there Oct 1 this yeaer for a week.
My understanding is the construction company working on replacing the Bonner Bridge on the Northern part of the Island cut an encased line under water while they were driving pilings.
Not just Ocracoke but as of this morning they issued mandatory evacuation of Hatteras Island which has 3-5 times the tourist population of Ocracoke.
Thank you all. My family has arrived safely after a gridlock of a drive as the entire population of the resort area changes over on Saturday at noon. Fifteen people and three large dogs in a house with nine bedrooms, nine and a half baths, and remarkably two dishwashers.
Makes me glad I’m in Saudi Arabia.