ELLIS — Midwest Energy crews still are attempting to determine what caused a power outage in the Ellis/Yocemento area Monday night.

According to Midwest spokesman Mike Morley, a breaker opened at the Knoll substation north of Hays at 7:06 p.m., cutting power to 1,487 customers.

Upon arrival, crews patrolled the line between the substation and Ellis, but found no problems.

“Determining it was safe to restore electricity, crews began bringing folks back on in groups to avoid potential overloads,” Morley said Tuesday morning.

The first group was restored at approximately 8 p.m. and all customers were back online by 8:30 p.m.

“With no damage to the line and no lightning storms in that area, we’re still working to determine why the breakers opened,” Morley said.