Electrician Red Seal · Question
A new 120 V receptacle in a commercial office is installed but fails to provide power to a desk lamp. The circuit breaker is ON. Using a voltmeter, the electrician measures 0 V between the hot (line) and neutral terminals of the receptacle. When measuring between the hot terminal and a known good ground, they also read 0 V. However, a voltage of 120 V is measured between the neutral terminal and the known good ground. What does this indicate?
Measuring 0 V between hot and neutral, and 0 V between hot and ground, but 120 V between neutral and ground, strongly indicates an open hot (line) conductor. Th
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Question: A new 120 V receptacle in a commercial office is installed but fails to provide power to a desk lamp. The circuit breaker is ON. Using a voltmeter, the electrician measures 0 V between the hot (line) and neutral terminals of the receptacle. When measuring between the hot terminal and a known good ground, they also read 0 V. However, a voltage of 120 V is measured between the neutral terminal and the known good ground. What does this indicate?
Answer options:
- An open neutral conductor ✅ An open hot (line) conductor
- A short circuit between hot and neutral
- A reversed polarity at the receptacle
Correct answer: An open hot (line) conductor
Explanation: Measuring 0 V between hot and neutral, and 0 V between hot and ground, but 120 V between neutral and ground, strongly indicates an open hot (line) conductor. The neutral is completing the circuit through the voltmeter back to the grounded service neutral, showing the 120 V potential, but the hot connection to the receptacle is interrupted, preventing any voltage from reaching the hot terminal.
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