300.9 Raceways at different temperatures
What changed in 300.9
Besides sealing, an approved method like a thermal break coupling can now be used to stop condensation in raceways crossing temperature zones.
Point by point
- There's now a second way to stop condensation inside raceways that run between warm and cold areas.
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- 2 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 300.7 in the 2020 NEC®.
Sealant used in raceways that run between warm and cold areas must now be identified as compatible with the insulation and conductors it touches.
Open the 2020 page →2023 NEC®No change
This section did not change from 2020 to 2023.
2026 NEC®RevisedYou're here
Besides sealing, an approved method like a thermal break coupling can now be used to stop condensation in raceways crossing temperature zones.
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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