90.5 Mandatory and permissive rules
What changed in 90.5
The explanatory material rules now say that when the code points to another standard without naming an edition, the latest edition applies.
Point by point
- When the code refers to another standard without naming an edition, the latest edition of that standard applies.
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- 2 more points on exactly what changed
- The 2020 rule next to the 2023 rule, side by side
- Why it changed
- What to do and check on the job
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This section across NEC® editions
2020 NEC®No change
This section did not change from 2017 to 2020.
2023 NEC®RevisedYou're here
The explanatory material rules now say that when the code points to another standard without naming an edition, the latest edition applies.
2026 NEC®Revised
Referenced standards must show their dates again, two annexes were dropped, and a new annex previews the planned new layout for the next edition.
Open the 2026 page →More 2023 changes in Article 90
This is a plain-English summary, not the NEC®'s exact wording. Always check the full section in the NEC® edition your area has adopted, plus any local amendments.
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