NEC 90.13: after 2023

What NEC 90.13 Sets Up

Article 90 is the front matter of the Code. It tells you what the NEC covers, how to read it, and how its rules get enforced. When the 2023 cycle reorganized and expanded Article 90, the stated goal was to make the introduction match the way the rest of the Code is actually structured and used in the field.

Section 90.13 sits inside that introductory framework. If you came up on the 2017 or 2020 books, you will not find it there. Anything past 90.9 in older editions is new territory, and the renumbering upstream means a quick cross-reference is worth doing before you quote chapter and verse to an AHJ.

The practical takeaway: Article 90 is no longer just 90.1 through 90.9. Know where your jurisdiction is in the adoption cycle before you argue a section number.

Adoption Status Drives Everything

The NEC is only enforceable where it is adopted. Per NEC 90.4, the authority having jurisdiction decides interpretation, approvals, and special permission. A section added in the 2023 cycle means nothing on a job governed by the 2020 book.

Before you cite 90.13 on a plan review comment or a correction notice, confirm two things: which edition the state or municipality has adopted, and whether any local amendments strike or modify Article 90 language. Several states adopt the NEC with amendments that remove or rewrite introductory sections.

Tip: Keep a printed or saved screenshot of the adoption ordinance for every jurisdiction you work in. When an inspector quotes the wrong edition, you want the document, not the argument.

Scope and What the Code Does Not Cover

NEC 90.2 lays out what the Code covers and, more importantly, what it does not. Utility-owned equipment on the line side of the service point, installations in ships and railway rolling stock, and certain mining and communications utility work are outside the scope. The post-2023 edits sharpened some of that language, including clarifications around large-scale PV, energy storage, and microgrids.

This matters on the ground when you hit the service point on a commercial job, or when you are tying into a utility-owned transformer pad. The Code stops where the utility's jurisdiction starts. Do not try to enforce Chapter 3 wiring methods on conductors the utility owns.

• Confirm the service point location on the utility's drawing or with the lineman.
• For PV and ESS, check 90.2(A) and (B) alongside Article 690 and Article 706.
• For medium voltage above the service point, the utility's construction standard governs, not the NEC.

Mandatory vs Permissive Language

NEC 90.5 is the section every electrician should have memorized. "Shall" is mandatory. "Shall be permitted" or "shall not be required" is permissive. Informational notes and Annexes are not enforceable unless specifically adopted.

When you read any section added or revised in the 2023 cycle, including the 90.10 and later additions, slow down on the verbs. A rule that says "shall be permitted to" gives you an option, not an obligation. Inspectors sometimes cite informational notes as if they were requirements. They are not, per 90.5(C).

Tip: If an inspector writes a correction based on an informational note, ask them politely to cite the mandatory rule the note is clarifying. Nine times out of ten, the actual rule is narrower than the note reads.

Code Arrangement and How to Navigate It

NEC 90.3 describes the structure: Chapters 1 through 4 apply generally, Chapters 5, 6, and 7 modify or supplement the general chapters for special occupancies, equipment, and conditions, Chapter 8 (communications) stands alone, and Chapter 9 is tables. Article 90 updates in 2023 did not change this arrangement but reinforced how special rules override general ones.

For a working electrician, that hierarchy is the fastest way to resolve apparent conflicts. A hospital corridor receptacle is governed by Article 517 first, then by 210 and 406 where 517 is silent. A hazardous location fitting is governed by Article 500 series, not the general raceway rules.

1. Start in Chapters 1 to 4 for the baseline requirement.
2. Check the Chapter 5, 6, or 7 article that matches your occupancy or equipment.
3. Apply the special rule where it modifies or adds to the general rule.
4. Use Chapter 9 tables for conductor fill, ampacity adjustments, and conduit sizing.

Field Application Checklist

The updates around NEC 90.13 and the surrounding 2023 additions are about clarity, not new installation requirements you will trip over in the field. The real risk is citing them in a jurisdiction that has not adopted the 2023 edition, or misreading permissive language as mandatory.

Before you hang your hat on any Article 90 section number post-2023, run this quick check:

• Which NEC edition is adopted here? Confirm with the building department website or the AHJ directly.
• Are there local amendments to Article 90 or to the specific article you are working under?
• Is the language mandatory ("shall") or permissive ("shall be permitted")?
• Does a Chapter 5, 6, or 7 article modify the general rule for this occupancy or equipment?
• Is the equipment on the load side of the service point, or is it utility-owned?

Article 90 does not tell you how to bend pipe or size a feeder. It tells you which rules apply and how to read them. Get that part right and the rest of the book gets easier to defend on the job.