Red Seal Electrician Practice
Electrical mathQuestion 1033 of 1506

A balanced Y-connected source has 277 V across each winding. What is the line voltage?

  1. 277 V
  2. 480 V
  3. 160 V
  4. 554 V
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Correct answer: 480 V

Line voltage in a Y is the winding voltage times the square root of 3: 277 V × 1.732 = 480 V.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 7.5: Three-phase Y and Delta Configurations

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Questions last reviewed: 18 October 2026