Thousands of commuters in San Francisco's Richmond District experienced overcrowded Muni buses and long waits this morning, when a garbage truck accidentally ripped down overhead wires at a busy intersection.

The accident occurred at around 6:15 a.m., when a garbage truck with a cherry picker arm struck the wires at Presidio Avenue and California Street, cutting off electricity to the area and throwing live wires to the ground, said Muni spokeswoman Maggie Lynch. No injuries were reported.

The intersection is a major artery for Muni, because it is only two blocks away from a bus yard, and the wires that were torn down serve several lines, including the 1-California, 3-Jackson and 4-Sutter.

"It had a pretty severe impact on service," Lynch said. "We won't be able to energize that area for a couple of days. We have to pull the rest of it down in order to rebuild it."

Muni replaced its usual two dozen trolleys with 16 buses to get commuters to work, and routed buses around the intersection, Lynch said. An estimated 30, 000-40,000 commuters were affected, Lynch said.

Work crews will be working around the clock to replace the wiring, but there was no estimate when the job would be completed.

The driver of the garbage truck provided identification information to Muni supervisors, and Lynch said it was likely that Muni would seek reimbursement for the costs of repairs.

"I would imagine that we'll be speaking with the company," Lynch said.