NEC 90.13: informational notes

What NEC 90.13 Covers

NEC 90.13 addresses informational notes, the explanatory text printed throughout the Code. These notes clarify intent, point to related articles, or reference outside standards like NFPA 70E or UL listings. They are not requirements.

The distinction matters on every job. A requirement can fail your inspection. An informational note cannot. Knowing the difference keeps you from over-building and, just as important, from under-building when you mistake a note for a rule.

Article 90 is the rulebook for the rulebook. Before you flip to 210, 250, or 310, understand how the Code talks to you. 90.13 tells you what informational notes are, how they behave, and why they sit alongside enforceable text.

Not Enforceable: The Key Distinction

Informational notes are explanatory only. NEC 90.5(C) spells this out directly: explanatory material, including informational notes, is not enforceable as a requirement of the Code. If an AHJ red-tags a job citing only an informational note, push back and ask for the mandatory rule.

Mandatory rules use "shall" or "shall not." Permissive rules use "shall be permitted" or "shall not be required." Informational notes use plain language and sit in smaller, italicized type under the rule they explain. Learn this visual cue and you will save time every inspection.

Field tip: If an inspector quotes a note, ask which numbered subsection contains the "shall." If they can't produce one, the note alone can't hold up the permit.

How to Spot Them in the Code Book

Informational notes are printed directly below the section they clarify. They are labeled "Informational Note" in bold, followed by the explanatory text in a smaller or italicized typeface. Some sections have multiple notes, numbered "Informational Note No. 1," "Informational Note No. 2," and so on.

Pocket editions and digital references preserve this formatting. In Ask BONBON and most code apps, notes are tagged separately so you can filter them out when you only want the enforceable language.

• Labeled "Informational Note" in bold
• Set in smaller or italic type
• Sits directly below the rule it explains
• Never contains "shall" or "shall not"
• Often points to another article or external standard

Common Examples You Will See

Informational notes show up across every chapter. A note under NEC 210.8 may reference ground-fault protection testing procedures in UL 943. A note under NEC 250.4 explains the performance intent behind grounding and bonding. A note under NEC 310.15 may direct you to ampacity calculation examples in Annex B.

Notes also commonly point to NFPA 70E for arc-flash and worker safety, NFPA 79 for industrial machinery, and NFPA 72 for fire alarm signaling. These external documents are themselves enforceable only when adopted by another code or contract, not by their mention in a note.

1. Cross-references to other NEC articles (for example, a note under 406.12 pointing to 210.52)
2. Pointers to NFPA standards (70E, 72, 79, 110)
3. Pointers to UL, ANSI, or IEEE product standards
4. Clarification of intent when language could be misread
5. Example calculations or typical applications

How to Use Them in the Field

Read the notes. They are the fastest way to understand why a rule exists and where adjacent requirements live. When you are troubleshooting or designing, notes often point you to the exact article you need next.

Use notes to build your argument. If you are explaining a design choice to a GC, a customer, or a plan reviewer, citing both the mandatory rule and its informational note shows you understand intent, not just letter. That matters during negotiation over gray-area installations.

Do not quote a note as the reason for a code violation. If a helper or apprentice writes up a deficiency based only on note text, correct it. The callout should cite the "shall" language in the parent section or subsection.

Field tip: When a plan reviewer pushes a comment that references a note, rewrite the response to cite the mandatory rule the note sits under. Review cycles get shorter fast.

Don't Confuse Notes With Exceptions

Exceptions are enforceable. They modify the parent rule and carry the same weight as the rule itself. An exception to NEC 250.32(B) changes how you handle grounded conductors to separate buildings. Miss the exception and you either over-install or violate the Code.

Informational notes do not modify rules. They explain them. The formatting is different: exceptions are labeled "Exception:" in bold and printed in the same weight as the rule. Notes are labeled "Informational Note" and printed lighter.

• Exception: enforceable modifier, equal weight to the rule
• Informational Note: explanatory only, not enforceable
• Both sit under the parent section, but only one can fail your inspection

Bottom Line

Informational notes guide your understanding. They do not dictate your install. Learn the visual cues, read them for context, and cite them when explaining intent. When a violation is on the line, pull the mandatory language from the numbered section and leave the note text as supporting material.

Every minute you spend getting comfortable with Article 90 pays off across the rest of the book. The Code is a tool. 90.13 tells you which markings on that tool are blades and which are labels.