UPDATE (9:20 a.m.) - PG&E officials tell KSBY News the cause of the outage was a tree limb that fell onto a power line along the 1200 block of Osos Street downtown San Luis Obispo.
PG&E says there may have been sparking during contact but there was no fire.
Officials say crews will be doing additional work to the tree where the limb fell "to ensure it does not create any new hazard.
UPDATE (7:45 a.m.) - San Luis Obispo police say a temporary top sign has been placed at Osos and Higuera streets downtown San Luis Obispo where stoplights are not fulling functioning following the overnight outage.
PG&E says power to everyone has been restored. Crews are assessing the cause.
UPDATE (4:45 a.m.) - According to PG&E's website, power has been fully restored.
The power for residents and businesses in downtown San Luis Obispo was fully restored at around 1:15 a.m. Friday.
(10:30 p.m., Thursday) - A power outage in San Luis Obispo is affecting more than 1,000 customers in downtown.
The outage was reported just after 10:30 p.m. on Thursday.
According to the San Luis Obispo Police Department, the outage could be due to a transformer that went out or a downed power pole.
Police say the outage runs from Broad Street to Osos Street on Marsh and Higuera.
According to PG&E's website, power is expected to be fully restored by 1:45 a.m. Friday.
This is a developing story and will be updated when new information becomes available.