When performing our vegetation management duties as required by law, we do our best to preserve the trees on your property. In some cases, however, problem trees or improperly planted trees pose too high a risk to public safety and electric system reliability and must be removed. If we don't comply with regulations, we put the public at risk, increase the possibility of outages and face hefty fines.
These are the regulations we follow:
General Order 95, issued by the California Public Utilities Commission (CPUC), requires a year-round clearance below power lines of a minimum 18 inches. New fire safety regulations require a minimum clearance of four feet year-round for high-voltage power lines in the CPUC-designated High Fire-Threat Districts.
PRC 4292 is administered by the California Department of Forestry and Fire Protection (CAL FIRE). It requires that we maintain a firebreak of at least 10 feet in radius of a utility pole. Tree limbs within the 10-foot radius of the pole must be removed up to eight feet above ground. From eight feet to conductor height requires removal of dead, diseased or dying limbs and foliage. This applies in the State Responsibility Area during designated fire season.
The fuel breaks are created around specific powerline poles that have pieces of equipment identified as non-exempt by CAL FIRE. Fuel breaks help protect our electric powerline poles from potential fire hazards.
PRC 4293, administered by CAL FIRE, requires a 4-foot minimum clearance be maintained for power lines between 2,400 and 72,000 volts, and a 10-foot clearance for conductors 110,000 volts and above. PRC 4293 also requires the removal of dead, diseased, defective and dying trees that could fall into the lines. This applies in the State Responsibility Area during designated fire season.
Following the Governor's January 2014 Drought State of Emergency Proclamation, the CPUC issued Resolution ESRB-4. The resolution directs utilities to take practicable measures necessary to reduce the likelihood of fires. Those measures include increasing vegetation inspections; removing hazardous, dead and sick trees and other vegetation near electric power lines and poles; sharing resources with CAL FIRE to staff lookouts adjacent to the utilities' property; and clearing access roads under power lines for fire truck access.
NERC FAC 003-4 is a Federal Energy Regulatory Commission (FERC)-approved standard implemented to eliminate transmission outages and resulting blackouts due to vegetation contact. The standard applies to all utilities across the United States and directs them to manage vegetation clearances between trees and power lines to ensure the reliable operation of the transmission system.
The standard applies to transmission line voltages carrying 200,000 volts and higher and certain lower voltages transmission lines identified as critical by the Western Electric Coordinating Council (WECC).