The City of Sitka is sending residents who have damage claims resulting from a recent power surge directly to the contractor’s insurance company.
At least 50 homes experienced appliance failures — mostly heat pumps — after a utility contractor snapped a guy wire over a week ago, creating a short between the city’s high voltage transmission lines and lower-voltage distribution lines.
Sitka utility director Bryan Bertacchi says electric grids in Alaska experience faults all the time — usually from downed tree branches, rodents or birds — and they’re cleared before customers are aware of any problem.
But the recent fault in Sitka was a different animal altogether.
“In this case it was a steel cable of large diameter,” Bertacchi said, adding that the fault was very brief. “Probably less than half a second that the fault occured before the protection worked to clear it. But still, significant high voltage levels likely to a lot of the community.”
The guy wire was broken by a utility contractor involved in an extensive water and sewer replacement under DeGroff St., at the intersection of Sawmill Creek Road. The latter is Sitka’s utility corridor, carrying the 69,000-volt transmission lines from Sitka’s hydroelectric projects into town. Below the three transmission lines is the local distribution line.
When the guy-wire snapped, it connected the high- and low-voltage lines, briefly sending an estimated 3-6 times more voltage to customers than normal, and apparently creating a show.
“And I think folks that were nearby saw quite a shower of sparks,” Bertacchi said.
Power was out for about four hours after the fault. Once electricity was restored, people began to notice problems.
Sitka municipal administrator Keith Brady says that city hall has logged calls from 48 residents so far whose home appliances may have been damaged by the surge. He says much depends on what was turned on at the time of the fault.
One appliance seemed especially susceptible to problems.
“You know, outside of water heaters, stoves, coffee makers, microwaves, the big livability problem we have is the heat pumps,” Brady said. “So it sounds like we have a lot of heat pump damage around town, and we want to make sure that people can live in their homes in the winter. We want to make sure that this gets moved as quickly as possible.”
Utility companies are generally not liable for “Acts of God” that damage property, but a contractor backing into support pole doesn’t fall under that exclusion. City Hall is directing all claims toward the contractor’s insurance company, Alaska Adjusters, LLC. A claim number has been established for damage connected to the incident.
And it wasn’t just homeowners. The surge took out “a very large surge arrestor” at Sitka’s Marine Street Substation, which is going to require a scheduled overnight power outage to replace. Also, Sitka has over 20 sewage lift stations — many with older pumps that don’t fire up even under normal conditions.
In addition to yeoman work by electric linemen to restore power, Sitka public works director Michael Harmon says his crews used portable pumps to keep Sitka’s sewage flowing in the right direction over the four-hour outage.
“If we would have had rains — we were very blessed that it was dry — we would have had to overflow sewer into the ocean in this event,” Harmon said.
The city at the moment can only speculate about why the outage was hard on heat pumps — and why only some of them. The geographic distribution of failures doesn’t really provide a clue. Bertacchi suspects it might have to do with which of Sitka’s three-phase transmission wires was first contacted by the broken guy-wire, although it ended up wrapped around all three.
At first, people thought it was just the DeGroff area downtown that was affected — but Bertacchi says that was not the case. And he also says this surge would have been difficult to protect against.
“My heat pump on my house failed on the north end of town,” Bertacchi said, “and I have a whole-house surge suppressor on my main panel. And I’ve never had a surge problem through any lightning strikes with that. But in this particular instance my own heat pumps failed.”
Bertacchi said he is filing a claim himself.
Sitka community affairs director Maegan Bosak says anyone planning to file an insurance claim from the surge should be prepared to document the damage.