320.80 AC cable ampacity
What changed in 320.80
When more than two AC cables are bundled in insulation, caulk or sealing foam, their ampacity now has to be adjusted, matching NM cable. MC and SE cable got the same rule.
Point by point
- Still required: AC cable in thermal insulation needs 90°C conductors, and its final ampacity is capped at the 60°C value in Table 310.16.
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This section across NEC® editions
2020 NEC®RevisedYou're here
When more than two AC cables are bundled in insulation, caulk or sealing foam, their ampacity now has to be adjusted, matching NM cable. MC and SE cable got the same rule.
2023 NEC®No change
This section did not change from 2020 to 2023.
2026 NEC®No change
This section did not change from 2023 to 2026.
More 2020 changes in Article 320
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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