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Project TL6975

SDG&E has received initial approval to run a new 12-mile transmission line (called TL6975) from San Marcos to Escondido.  A 2.8 mile segment involves additional/NEW power line poles installed 30 feet east of the poles that currently run through our communities.

The CPUC has posted their initial approval to SDG&E's application for Project TL6975. The public comment period will end on May 30th at 5pm.
For the latest information go to the CPUC's website or go to


San Diego Gas & Electric Co. San Marcos-Escondido Transmission Line (TL 6975) 69kV Project

(Application No. A.17-11-010)


Welcome to the California Public Utilities Commission (CPUC) website for the California Environmental Quality Act (CEQA) review of San Diego Gas and Electric's (SDG&E’s) San Marcos to Escondido Transmission Line (TL 6975) 69kV Project (proposed Project). An application for this project was submitted to the CPUC on November 15, 2017 (Application A.17-11-010). This site provides access to public documents and information relevant to the CEQA environmental review process.



SDG&E, in its CPUC application (A.17-11-010), filed on November 15, 2017, requests a Permit to Construct (PTC) the San Marcos-Escondido TL 6975 69kV Project.

The proposed project is subject to CEQA review because the CPUC has been presented with a discretionary action to approve or deny SDG&E’s PTC application. Before making a decision about SDG&E’s application, the CPUC is required to analyze potential environmental impacts associated with the project and present the findings in an environmental document for public review and comment. This website provides access to public documents and information relevant to the CEQA review process.


Project Overview


The proposed Project (see Location Map ) would occur in the cities of Carlsbad, Escondido, Vista and San Marcos, and in unincorporated  San Diego County, California.  Two auxiliary staging yards located in the city of San Diego are proposed for Project use. The proposed Project components at each location are summarized (by segment) below:

  • Segment 1 Rebuild (San Marcos Substation-Melrose Tap). Rebuild approximately 1.8 miles of an existing 69kV circuit (TL 680C) to create a double circuit from San Marcos Substation to Melrose Tap. Construction at San Marcos Substation including installation of a new circuit breaker par, seven piers, and an A-frame for the new line. Along Segment 1, all wood pole structures would be replaced with steel poles; porcelain insulators would be replaced with polymer insulators.

  • Segment 2 New Build (Melrose Tap-Meadowlark Junction).  Construct 2.8 miles of new single-circuit 69kV overhead power line on new steel poles in the existing SDG&E transmission corridor from Melrose Tap to Meadowlark Junction adjacent to existing TL 13811/13835 power line, approximately 50-feet east of the centerline of the existing structures.

  • Segment 3 Reconductoring/Re-energizing (Meadowlark Junction-Harmony Grove Rd to Escondido Substation). Transition new line (described under Segment 2, above) and reconductor approximately 7.4 miles of power line; remove and replace existing copper conductors with new 636 ACSS/AW conductors and existing porcelain insulators with polymer insulators; construction at the existing Escondido Substation to accommodate new circuit.


The proposed Project would include a combination of new overhead single-circuit electric power line structures, rebuild of existing structures from single circuit to double circuit, and the reconductoring and re-energizing of existing conductors.  The majority of the new build and reconductored portions of the power line would occur within existing rights-of-way (ROW)s. A portion of the Project (Segment 1 rebuild) would require the widening of existing ROW.  

The purpose of this proposed Project is to ensure the reliability of the transmission system, meet the State of California’s policy goals, accommodate load growth, and improve system efficiency in SDG&E’s service territory. SDG&E has identified the following objectives:

  1. Eliminate North American Electric Reliability Corporation (NERC) Category P0 (Cat A) and Category P1 (Cat B) violations on existing TL 684 (Escondido to San Marcos) and TL 680C (San Marcos- Melrose Tap) and;

  2. Meet mandatory NERC reliability criteria in the Escondido Area Load Pocket and alleviate the existing 69 kV congestion at the Escondido/ San Marcos Substations.   


Application and Proponent’s Environmental Assessment

On November 15, 2017, SDG&E filed an application (A.17-11-010) for a PTC which included a Proponent’s Environmental Assessment (PEA) for the proposed Project pursuant to Rule 2.4 of the CPUC's Rules of Practice and Procedure."

Go to the CPUC website for further information and related documents at


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