Nearly 650 customers in downtown Santa Barbara were left without power Thursday due to an equipment failure, according to the Southern California Edison Co.

An underground component failed in the 1200 block of Chapala Street shortly after noon, said company spokeswoman Patricia Bartoli-Wible.

Crews were dispatched to the scene and were trying to isolate the problem, Bartoli-Wible said, adding that about half the affected customers were back on online within 15 minutes.

Numerous business in the downtown corridor were affected, as were homes and traffic signals in the area.

Among those affected was Santa Barbara City Fire Station 1 on Carrillo Street, the department’s headquarters, which is equipped with an emergency power generator that allowed the facility to remain in operation.

Fire officials were urging motorists to be patient and use caution in the downtown area where intersections were without operational traffic signals.

Bartoli-Wible said she did not know when all customers would have power restored, but said she expected it “very shortly.”

As of 4:30 p.m., 35 customers in the area of Chapala, Victoria Street, and Anapamu Street remained without power, she said, adding that crews would be working into the night till all power is restored.

An unrelated planned outage was affecting a small number of customers in the area of Patterson Avenue and Perejo Drive in Goleta, Bartoli-Wible said.

— Noozhawk executive editor Tom Bolton can be reached at tbolton@noozhawk.com. Follow Noozhawk on Twitter: @noozhawk, @NoozhawkNews and @NoozhawkBiz. Connect with Noozhawk on Facebook.