CPUC Rule 20 Programs:
Conversion of Electric Power Lines

Rule 20


To help improve community aesthetics and meet our commitment to provide clean, safe and reliable energy to our customers, we continuously make upgrades to our electric infrastructure. This includes working in partnership with local governments to underground our overhead electric power lines through the Rule 20 programs, as authorized by the California Public Utilities Commission (CPUC). Currently, more than 10,500 miles of SDG&E’s electric distribution lines, or about 60% of the regional distribution system, is underground. 

Some of the benefits of overhead-to-underground conversion include: 

  • Beautification of local neighborhoods and commercial districts 
  • Increased grid resiliency, as undergrounded power lines can remain energized during Public Safety Power Shutoffs, which are enacted as a measure of last resort to prevent wildfires during extreme fire weather conditions
  • Reduced likelihood of power outages caused by vehicles accidents that damage power poles

Because undergrounding projects are costly and tend to benefit those in the immediate vicinity the most, the CPUC limits the funding of conversions by the general ratepayer under its Rule 20 program. 

Rule 20

SDG&E construction crew install electrical conduit in a trench, intersecting a substructure, for underground electric facilities.

What is Rule 20

In 1967, the California Public Utilities Commission (CPUC) established Electric Tariff Rule 20, which defines policies and procedures for California’s investor-owned electric utilities (IOUs), including SDG&E, to convert overhead power lines and other equipment to underground facilities. Cities identify overhead lines that they wish to convert to underground and, in consultation with their investor-owned utility, determine if the conversion project qualifies. Aesthetic enhancement has been the primary focus of the program.

The Rule 20 program is currently divided into four subprograms that provide diminishing levels of ratepayer contributions to projects – Rule 20A, 20B, 20C and 20D. Rule 20D is currently only available in SDG&E’s service territory and applies specifically to undergrounding for wildfire mitigation. 

What is Rule 20A

Rule 20A is a subprogram of Rule 20 that allocates ratepayer-funded work credits to California’s communities to fund utility underground conversion projects. Rule 20A projects are nominated by cities or counties and are paid for by customers through their electric utility bill. The City of San Diego has a separate undergrounding program in partnership with SDG&E that is not funded by general ratepayer.

Rule 20

SDG&E construction crew excavate trench for electrical conduit and substructures.

Recent Changes to Rule 20

On June 3, 2021, the CPUC issued a decision that significantly revised the rules for the Rule 20 program.

The decision is officially called “Phase 1 Decision Revising Electric Rule 20 and Enhancing Program Oversight.”

This Phase 1 decision revised Electric Rule 20 as follows: (a) discontinues new work credit allocations for Electric Rule 20A projects after Dec. 31, 2022, (b) clarifies Electric Rule 20A project eligibility criteria and work credit transfer rules, and (c) enhances program oversight.

Per the Commission’s direction, SDG&E has notified each community of its existing work credit balance.

Phase 2 of the proceeding will address a number of issues not addressed in Phase 1. To complete Phase 2, the CPUC has extended the statutory deadline for 12 months after the effective date of the Phase 1 decision (June 2022).

More Information

563.29 KB
Electric Rule 20 Guidebook
Electric Rule 20 Guidebook
209.87 KB
Rule 20 Nondisclosure Agreement
Rule 20 Nondisclosure Agreement