Equipment & SystemsQuestion 287 of 521
NEC 450.9 requires that transformer ventilation openings be arranged so that they:
a.Are always fitted with fans
b.Face downward only
c.Are not blocked by walls or obstructions, allowing required airflow to dissipate heat
d.Are sealed to keep out dust
Explanation
NEC 450.9 requires ventilation so transformers can dissipate full-load losses without exceeding temperature ratings; openings must not be blocked by walls or obstructions. Forced ventilation is not always required, and sealing openings would defeat cooling.
Law Reference: 2023 NEC §450.9Practice all 521 questions free — no signup required.
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