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Thursday, January 27, 2022
Question:
Greetings,
What is minimal breaker amp size allowed in new homes?
Mark Brown
A
Answer:
Hi Mark,
Section 210.11 addresses required branch circuits and number of branch circuits. It indicates that branch circuits for lighting and for appliances, including motor-operated appliances, shall be provided to supply the loads calculated in accordance with 220.10. In addition, branch circuits shall be provided for specific loads not covered by 220.10 where required elsewhere in this Code and for dwelling unit loads as specified in 210.11(C). The minimum number of branch circuits shall be determined from the total calculated load and the size or rating of the circuits used. In all installations, the number of circuits shall be sufficient to supply the load served. In no case shall the load on any circuit exceed the maximum specified by 220.18. That said, 15-ampere circuit breakers are usually the smallest circuit breakers installed in dwelling units, but as far as we are aware, there is no minimum size indicated, so smaller breakers could be installed depending on how the load was divided up after calculations based on square footage were done. Also, fuses could be used and sized to protect the branch circuit, which is less common, but still could be installed to meet the minimum requirements in the NEC.