This type of event is rare. The line itself can actually burn. You're talking about an extremely intense hot fire.
EPB officials were still trying to figure out Tuesday what caused a 46,000-volt transmission line to catch fire and knock out power Monday night to 15,188 customers in South Chattanooga, East Ridge and North Georgia.
The fire occurred on a transmission line off 37th Street in Chattanooga, EPB spokesman John Pless said.
"This type of event is rare," Pless said. "The line itself can actually burn. You're talking about an extremely intense hot fire."
Carrie Saynes, who lives off 34th Street, said, "The whole sky lit up like a bluish-green color and you could hear a very loud buzzing sound."
That jibes, Pless said, with a fire on a high-voltage line, which gives off a "greenish, bluish glow - especially at night."
It's hard to figure out what caused the transmission line fire, he said, because the intense fire destroyed much of the physical evidence. Strong winds or lightning from the storm earlier Monday could be to blame, he said.
EPB employees monitor the power system from EPB's control room."It could have been that an insulator was broken on that wire," Pless said.
EPB's "smart grid," or high-tech electrical distribution system, allows operators to look back at events to see what went wrong, Pless said, sort of like the "black box" flight recorder that helps investigators understand a plane crash.
"The smart grid is providing lots of data that we can go back and investigate," he said.
Most of the 15,188 residents, about 9 percent of EPB's roughly 175,000 customers, had their power back on in an hour, Pless said.
Another complication was someone had dumped concrete and cement on the path to the transmission pole, Pless said, and EPB had to call in a bulldozer crew and spend several hours clearing a path to the damage and repairing it.
(Staff writer Ellis Smith contributed to this report.)
Contact staff writer Tim Omarzu at tomarzu@timesfreepress.com or www.facebook.com/tim.omarzu or twitter.com/TimOmarzu or 423-757-6651.