NEC 2026 Compatible

What is the rated primary current for a 45 kVA, 480V primary, 3-phase transformer?

Journeyman LevelšŸ“‹ NEC 450.3(B)Transformers
Circuit Diagram
Single-Phase Transformer ā€” NEC 450.3 OCPD Primary 450.3(B) ā‰¤125% 480V Primary Neutral 120V 120V Secondary 240V SEC PNL 120/240V Turns Ratio 4:1 (480:120) OCPD Sizing ā€” NEC 450.3(B): Primary only protection (no secondary OCPD): Primary OCPD ā‰¤ 125% of primary FLA Primary + secondary protection: Primary ā‰¤ 250% | Secondary ā‰¤ 125% I_primary = kVA Ɨ 1000 / V_primary | I_secondary = kVA Ɨ 1000 / V_secondary
A

54.1 amperes

B

62.5 amperes

C

93.8 amperes

D

108.3 amperes

Explanation & Direct Citation

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