The accident occurred on Risa Road off of Mt. Diablo Boulevard.
PG&E spokeswoman Tamar Sarkissian said the truck snagged a telecommunications line and brought down the pole and some PG&E wires, resulting in a power outage that affected 51 PG&E customers.
Lafayette police alerted residents about the situation via phone and email shortly after 9 a.m., saying there was a "severe electrical hazard" on Risa Road because of a downed high-voltage power line.
Police advised residents to stay indoors.
Sarkissian said, however, that because of a built-in safety mechanism, there was no danger to the public.
"The fuse blew the moment that line made contact with the ground and it was immediately de-energized," she said.
However, she said, residents should steer clear of fallen power lines.
"If you see a downed line, always assume it's live," Sarkissian said. "Keep yourself and others away, and call 911."
She said it could take several hours to restore power to the customers affected by the outage.