Red Seal Electrician Practice
Meters and troubleshootingQuestion 1024 of 1506

Why can a voltmeter or an ammeter not show the phase rotation of a live three-phase system?

  1. They are not accurate enough for use on a three-phase supply
  2. They read only DC values and cannot read AC at all
  3. Magnitudes are the same in either sequence
  4. They change the phase sequence when they are connected
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Correct answer: Magnitudes are the same in either sequence

A special instrument, such as a lamp-and-capacitor detector, is needed.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 7.3: Phase Rotation

Practice meters and troubleshooting

Questions last reviewed: 18 October 2026