TARGETED UNDERGROUNDING IN
HIGH FIRE RISK AREAS
UNDERSTANDING THE FACTS
Faced with the ongoing threat of more frequent and catastrophic wildfires, California needs more resilient infrastructure. Southern California Edison continues to strengthen its electric grid, using innovative tools, technologies, and practices to further protect customers and communities from the ongoing risks of wildfires. More than 40% of the primary distribution lines in SCE’s high fire risk areas are undergrounded. To further reduce wildfire risk cost-effectively and expeditiously, SCE continues to replace bare wire with covered conductor (coated wire). By the end of 2025, SCE expects to have hardened nearly 90% of its total distribution power lines, prioritizing its riskiest areas.
TARGETED UNDERGROUNDING AS A WILDFIRE MITIGATION MEASURE Underground systems can help reduce the risk of wildfires and increase reliability during high winds and storms by reducing the exposure of electrical infrastructure to extreme weather conditions. We are identifying the highest risk power lines to underground.
Customers will continue to see other equipment overhead, including telephone, cable and internet lines.
SCE has identified a subset of high fire risk areas as “Severe Risk Areas” where we have determined that for public safety reasons it is prudent to significantly reduce ignition risk by undergrounding, if not already hardened with covered conductor.
Targeting undergound criteria include:
• limited exit and entry points to communities • exceptionally high potential consequence (could burn > 10,000 acres within 8 hours)• high burn frequency • communities of elevated concern• high wind speeds exceeding covered conductor Public Safety Power Shutoff thresholds • operational feasibility
TARGETED UNDERGROUNDING REQUIRES EXTENSIVE PLANNING AND EARLY COMMUNITY ENGAGEMENT Undergrounding power lines take much longer to construct, are more costly, and are more difficult to maintain and repair than overhead infrastructure, particularly in mountainous and rocky terrain.
Typically, targeted undergrounding can take two to four years, and possibly longer, whereas covered conductor can be installed in less than two years. SCE will work closely with local cities and counties and engage impacted customers early in the process, especially concerning easement acquisition.
Mitigation Comparison
INITIATE
~2-3 MONTHS
• Determine scope
based on risk model
• Finalize project
timelines
• Develop detailed
scope
PLAN
~9-15 MONTHS
• Initiate early permit
application(City/County
CalTrans)
• Initiate Government
Lands
• Initiate Environmental
SCHEDULE
~9-15 MONTHS
• Perform standard
permitting and
easement processes
• Perform environmental
clearance process
• Obtain Additional
Agency Permits
EXECUTE
~5-15 MONTHS
• Excavation, trenching,
and paving
• Installation/removal of
equipment
Approximate Average
Lifetime Cost/Mile (Millions) Deployment Speed (Months) Undergrounding Undergrounding
Covered Conductor Covered Conductor
~$700,000
~$2.9M
to
~$4.5M
16-24+
25-48+
MONTHS
MONTHS
TRENCHING BACKFILLING
REMOVING
OVERHEAD
Construction Process During Execution
Undergrounding Timeline
FOR MORE INFORMATION
Visit sce.com/tug, email
[email protected], or leave
a voicemail for the project team
on its dedicated phone voicemail
box at 1-888-331-0010.
Updated: 4/3/24
ATTACHMENT #4
DPW: 850-20\ev\Council\2025\082625\SCE Underground Easement Att 4.pdf