October 11, 2012 at 6:11 PM
Storm after long dry spell may trigger power outages
We already know that bright, outside light called the sun will disappear when inevitable overcast skies and rain return to Seattle as soon as tomorrow. But Seattle City Light says electric light inside your home could suddenly disappear along with it — at least initially.
That’s because rain after long dry spells such as the one Seattle had this summer can trigger power outages in a few ways, according to Pawel Krupa, City Light systems control director. One way is dust that piles up on overhead power lines during dry weather can cause electricity leakage or short circuits when they get wet.
“You might hear a buzzing sound when this starts to happen,” Krupa said in a release. “That sound is the coating of the insulators burning off. When the coating is gone, a short circuit happens, creating an outage.”
Dry weather makes underground electrical systems more problematic too, he said. Underground lines are insulated and designed to float in water and become more fragile in dry weather.
“If the insulation on an underground cable cracks, any water in the vault will cause a short,” Krupa said.
Dry weather also makes trees and their branches more brittle and more likely to down power-lines in a storm.
“Even though City Light will do more than 625 miles of power line trimming this year, we can’t protect against every falling tree,” said Brent Schmidt, manager of the utility’s Vegetation Management program in the release. “We would like to know when there are conflicts between trees and wires, especially if there is any arcing or sparking.”
Customers who need help or more information taking care of potentially brittle trees can call City Light at 386-1733 or check out its website. They’re also encouraged to prepare for outages by having emergency kits handy and reviewing safety tips such as not going anywhere near a downed power line.
Eventually heavier rains will wash away the dirt and dust, though, and the risk for power outages will go down, according to the utility.
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The Today File is a general news blog featuring real-time coverage of Seattle and the Northwest. It is reported by the news staff of The Seattle Times and edited by Assistant Metro Editor Nick Provenza.
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