Charlie Tracy and a team of Oregon Trail Electric Cooperative employees spent much of Wednesday, July 7, trying to solve an electrical mystery.

But the investigation has so far proved fruitless.

And Tracy, who is the director of engineering for OTEC, concedes that the mystery might continue to stymie the cooperative’s sleuths.

“Given where we are, it’s unlikely that we’ll know what caused (the outage),” Tracy said on Thursday afternoon.

The outage, which lasted for about two hours on Wednesday morning, affected around 8,000 OTEC members, including all of Baker City, Baker Valley, Haines and North Powder.

Although a precise solution remains elusive, here’s what Tracy and other OTEC officials know:

The power went out when a circuit breaker opened at the Quartz substation, near the landfill off Highway 30 a few miles southeast of Baker City.

That breaker, like the ones in the electrical panel in homes and businesses, is a safety measure, designed to cut the flow of power when there’s a short circuit.

The outage had such a widespread effect because the Quartz substation, which is owned by Idaho Power Company, is along the transmission line that serves all of Baker Valley, Tracy said.

That line brings power generated at Idaho Power’s dams on the Snake River, and from wind farms in eastern Baker County.

Restoring power to a room in your home is usually a simple matter of flipping a plastic lever on the breaker box.

The process isn’t dramatically different at a substation, Tracy said — but the potential danger is many factors greater due to the much higher voltage.

Public and employee safety is the highest priority for OTEC, he said, so workers didn’t reset the substation breaker, thus restoring power, until they had investigated to ensure that doing so doesn’t pose a hazard.

For instance, if a power line is down, and then reenergized, it could harm people or start a wildfire, Tracy said.

With Wednesday’s outage, OTEC officials could isolate the problem — what engineers call a fault — but only to a certain degree.

Tracy said only a fault on a transmission line would have tripped the substation circuit breaker. Damage to a neighborhood feeder line, for instance, would not have had that effect because of the way the power distribution system is designed.

OTEC, which has monitoring equipment on its lines, also could determine that the fault happened “downstream” of the substation — between it and the rest of the distribution system that extends through Baker City to North Powder — rather than “upstream,” or between the Idaho Power dams and the substation.

But even with that level of detail, Tracy said OTEC workers had approximately 10 miles of transmission line to examine for possible faults before it was deemed safe to reenergize the lines.

“We need to be sure there’s no hazard,” he said.

Because OTEC employees could determine that certain areas were safe, and not the source of the fault, power was restored to some parts of the valley sooner than others, Tracy said.

Although the exact cause, and location, of the fault is unknown, Tracy said it had to be a “transient” issue — which is to say, a temporary one.

Had the fault resulted from a failed insulator or other equipment, or from an accident such as car crashing into a pole, OTEC employees would have found the problem during their patrols.

And even if they hadn’t, if the fault had remained, the circuit breaker would have opened again when the lines were reenergized.

Tracy said faults don’t have to be obvious things such as a tree toppling across a transmission line.

A length of baling twine can wrap around a line and cause a short circuit. The electricity would in effect “vaporize” the twine, though, leaving no evidence of what happened, he said.

Regardless, Tracy said OTEC’s system is designed to make outages rare — and widespread outages even more so.

He said the workers who were investigating the outage Wednesday morning, although thorough in their patrols, were also working as quickly as possible.

“We are keenly are of the hardship even a two-hour outage causes our members,” he said. “We are aware that the clock is ticking.”