Services & DistributionQuestion 49 of 521
Conductors are connected to a transformer secondary without an OCPD at the secondary terminals. What set of rules governs their length and sizing?
a.The small-conductor rule 240.4(D)
b.The service-entrance rules of Article 230
c.There are no restrictions
d.The transformer secondary/tap rules of 240.21(C)
Explanation
Per 240.21(C), transformer secondary conductors without secondary protection must follow specific tap rules limiting length (e.g., 10 ft or 25 ft) and minimum ampacity. Article 230 covers services, and 240.4(D) covers small conductors; unrestricted runs are never permitted.
Law Reference: 2023 NEC §240.21(C)Practice all 521 questions free — no signup required.
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