Code Q&A: Conductor Size for Class 1 Circuits

Your most pressing National Electrical Code (NEC) questions answered

Q. What is the smallest conductor allowed by the NEC for Class 1 control and signal circuits?

A. Conductors of sizes 18 AWG and 16 AWG installed in a raceway, enclosure, or listed cable are permitted for Class 1 circuit conductors if they don’t supply a load that exceeds the ampacities specified in Table 402.5. Conductors of 14 AWG and larger must not supply loads greater than the ampacities given in 310.15 [725.49(A)]. In additio

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