501.10 Class I wiring methods
What changed in 501.10
TC-ER-HL is allowed in more places, Type P cable was added, and more corrosion-resistant options were added. Class II got similar changes.
Point by point
- Class I, Division 1 wiring methods gained two cable types, TC-ER-HL and Type P, listed as 501.10(A)(1)(6) and (7).
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- 4 more points on exactly what changed
- The 2017 rule next to the 2020 rule, side by side
- What to do and check on the job
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This section across NEC® editions
2020 NEC®RevisedYou're here
TC-ER-HL is allowed in more places, Type P cable was added, and more corrosion-resistant options were added. Class II got similar changes.
2023 NEC®Revised
Threaded RMC and IMC with a supplemental corrosion-protection coating are now named as acceptable Class I, Division 1 wiring methods.
Open the 2023 page →2026 NEC®Revised
Class I, Division 1 and 2 wiring methods are now organized into tables.
Open the 2026 page →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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