300.6 Protection from physical damage
What changed in 300.6
The roof decking rule now covers every roof deck type and all wiring methods, and the bushing on 4 AWG and larger can go on after the pull.
Point by point
- Roof deck spacing now applies to every type of roof deck, not just metal-corrugated decking.
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- 3 more points on exactly what changed
- The 2023 rule next to the 2026 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®Revised
Found at 300.4 in the 2020 NEC®.
Where 4 AWG and larger conductors enter an enclosure from a raceway, a listed smooth-edged metal fitting now counts as protection, not just an insulating fitting.
Open the 2020 page →2023 NEC®Revised
Found at 300.4 in the 2023 NEC®.
Under metal roof decking, a new concrete exception was added and the RMC/IMC exception now depends on the fittings. Protective fittings for 4 AWG and larger go on before the pull.
Open the 2023 page →2026 NEC®RevisedYou're here
The roof decking rule now covers every roof deck type and all wiring methods, and the bushing on 4 AWG and larger can go on after the pull.
More 2026 changes in Article 300
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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