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San Marcos, CA Building Safety: Electrical Permits (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Adopted code
2025 California Electrical Code, Title 24 Part 3
Based on
2023 National Electrical Code, Chapters 1-9
Copper wire rule
Required for No. 6 or smaller conductors
Aluminum wiring
Feeder conductors only, oxidation controls required
NM cable limit
Barred above 3 stories and in most nonresidential
Undergrounding
Required for new development's service conductors

Summary

San Marcos wires its permitting to the 2025 California Electrical Code, adopted by reference under Municipal Code Section 17.12.010 and based on the 2023 National Electrical Code. The City then layers on local amendments, including a copper-wire rule for small conductors and an undergrounding mandate for new development's service lines.

The 2025 California Electrical Code, California Code of Regulations, Title 24, Part 3, based on the National Electrical Code 2023 Edition, Chapters 1 through 9, Appendices A, B, C, and G, published by the National Fire Protection Association ("NFPA"), is adopted by reference subject to the amendments contained in this Chapter.

(Ord. No. 2019-1478, Exh. A, § 1.D, 10-22-2019; Ord. No. 2022-1526, § 1.D(Exh. A), 10-25-2022; Ord. No. 2025-1575, § 1.D(Exh. B), 1-13-2026)

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 14 Update 1).

Full Breakdown

12 adopts the 2025 California Electrical Code, California Code of Regulations Title 24 Part 3, itself based on the 2023 National Electrical Code Chapters 1 through 9 and Appendices A, B, C, and G published by the National Fire Protection Association, subject to the local amendments that follow in the chapter. 3. 3(B) to mandate copper wire for any No. 6 or smaller conductor; aluminum wiring is allowed only for feeder conductors where measures prevent oxidation, and any aluminum branch-circuit conductor of No. 6 or smaller requires continuous inspection by an independent testing agency the City approves, checking proper torquing and oxidation-inhibitor installation at every termination.

12 to bar Type NM, NMC, and NMS nonmetallic sheathed cable in any building over three stories, and bars it in nonresidential buildings entirely unless the cable carries a listed insulation rating of at least 75 degrees Celsius (167 degrees Fahrenheit).

Violations & Fines

Electrical work performed without a permit, or that doesn't conform to the adopted 2025 California Electrical Code and San Marcos's local amendments, is subject to standard Building Code enforcement: the Building Official can red-tag the installation, require it to be exposed for reinspection, and order noncompliant aluminum branch wiring or undersized nonmetallic cable removed and replaced before power is connected or service is restored.

Frequently Asked Questions

What electrical code applies to construction in San Marcos?
The 2025 California Electrical Code, California Code of Regulations Title 24 Part 3, based on the 2023 National Electrical Code, applies citywide under Section 17.12.010, along with the local amendments covering wiring materials and service undergrounding in the rest of Chapter 17.12.
Can I use aluminum wiring in San Marcos?
Only for feeder conductors, and only where measures prevent oxidation of the aluminum. Copper is mandatory for any conductor No. 6 or smaller under Section 17.12.030, and any smaller aluminum branch-circuit wire needs continuous inspection by a City-approved independent testing agency for proper torquing.
Does San Marcos require underground utility lines for new construction?
Yes, when the City requires it. Section 17.12.020 requires new development, redevelopment, additions, and remodels to underground the service conductors fronting the project, covering power, cable, telephone, and fiber lines, consistent with General Plan Land Use Policy 17.3.
Is nonmetallic sheathed cable allowed in San Marcos buildings?
Not above three stories, and not in nonresidential buildings unless it carries insulation rated at least 75 degrees Celsius. Section 17.12.090 bars Type NM, NMC, and NMS cable outside those limits regardless of what the base National Electrical Code otherwise permits.

Sources & Official References

Other rules in San Marcos

All San Marcos rules

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