450.2 Interconnected transformers
What changed in 450.2
The old "transformer" definition in 450.2 was replaced with an enforceable rule about individual and interconnected transformers.
Point by point
- 450.2 no longer defines the word transformer; a general definition now sits in Article 100.
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- 3 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 old "transformer" definition in 450.2 was replaced with an enforceable rule about individual and interconnected transformers.
2026 NEC®No change
This section did not change from 2023 to 2026.
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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