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2029 Future PI: 240.4(H)

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wwhitney

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Berkeley, CA
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Since I missed the 2026 PI deadline. Cheers, Wayne

240.4 Protection of Conductors.

Conductors, other than flexible cords, flexible cables, and fixture wires, shall be protected against overcurrent in accordance with their ampacities specified in 310.14, unless otherwise permitted or required in 240.4(A) through (H).
. . .
(H) Dwelling Unit Service and Feeder Conductors.
Dwelling unit service and feeder conductors shall be permitted to be protected against overcurrent at the ampacity values in 310.12 at the service or feeder ratings specified in 310.12.

Statement of Problem and Substantiation for Public Input

310.12 does not specify ampacity values; rather it assigns a higher "service rating" or "feeder rating" to certain conductors for single phase dwelling unit supplies. As such, the language in 240.4(H) needs to specify that overcurrent protection may be in accordance with this service or feeder rating, rather than with the conductor ampacity.
 
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