Pierce County power outage tied to routine test

The substation impacted by today's power outage in Pierce County. (Courtesy: Tacoma Power Staff)
The substation impacted by today's power outage in Pierce County. (Courtesy: Tacoma Power Staff)

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Thousands of homes and businesses in Pierce County went dark Wednesday morning when the power unexpectedly went out. Around 55,000 Tacoma Public Utilities and Peninsula Light customers were affected.

While an investigation into the cause is ongoing, officials with TPU said they can trace the outage to a routine test of the transmission systems. 

TPU crews were testing the ability of equipment to reliably detect faults in the system, said Joseph Wilson, the deputy general manager for power delivery at the utility. The test resulted in equipment not being tested to de-energize portions of the utility’s network. That included the transmission line that goes across the Narrows, which feeds Peninsula Light Co. customers. 

“We are very regretful that so many customers were impacted,” Wilson said. “We truly try to serve our customers with reliable power and regret that this was the outcome of today’s test.”

A more comprehensive investigation into why the outage occurred could take at least a week, Wilson said.

“We still have some more testing to do, so we need to understand what happened,” Wilson said. 

Power for TPU customers was back on in less than an hour and once TPU power was restored, Peninsula Light crews worked to get power back to its customers.