 SDG&E implemented their system restoration plan and cautioned its customers to expect a prolonged outage.The outage appears to have been caused by the actions of an employee at APS's North Gila substation in Arizona, and it is unknown why safeguards did not keep the outage limited to the Yuma area.By Friday morning on the 9th, power had been restored to all 1.4 million SDG&E customers.