Which of the following conditions will cause a ground fault circuit interrupter (GFCI) to disconnect AC power?
The correct answer is B: Current flowing from one or more of the hot wires directly to ground. The condition that will cause a ground fault circuit interrupter (GFCI) to disconnect AC power is current flowing from one or more of the hot wires directly to ground. GFCIs detect current imbalance (current going to ground instead of returning through neutral) and trip. For amateur radio operators, this is critical electrical safety. Understanding this helps ensure safe electrical operation.
Exam Tip
GFCI trips = current flowing from hot wires directly to ground. Think 'G'FCI = 'G'round 'F'ault 'C'urrent 'I'mbalance. GFCIs detect current imbalance (current going to ground instead of returning through neutral) and trip. Not hot to neutral (normal), not overvoltage - just current to ground.
Memory Aid
"GFCI trips = current flowing from hot wires directly to ground. Think 'G'FCI = 'G'round 'F'ault. GFCIs detect current imbalance (current going to ground instead of returning through neutral) and trip. Critical electrical safety protection."
Real-World Application
A GFCI: It monitors current flow. If current flows from a hot wire directly to ground (instead of returning through neutral), the GFCI detects the imbalance and trips, disconnecting AC power. This protects against electric shock - if you touch a hot wire, current flows through you to ground, and the GFCI trips. Current to ground causes GFCI to trip.
National Electrical CodeKey Concepts
Why Other Options Are Wrong
Option A: Incorrect. Current flowing from hot to neutral is normal operation - GFCI doesn't trip on normal current flow. Hot to neutral is normal.
Option C: Incorrect. Overvoltage on hot wires doesn't cause GFCI to trip - GFCIs detect current imbalance, not overvoltage. Overvoltage isn't detected.
Option D: Incorrect. Since A and C are not correct, 'all of the above' cannot be correct. Only current to ground causes GFCI to trip.
题目解析
The correct answer is B: Current flowing from one or more of the hot wires directly to ground. The condition that will cause a ground fault circuit interrupter (GFCI) to disconnect AC power is current flowing from one or more of the hot wires directly to ground. GFCIs detect current imbalance (current going to ground instead of returning through neutral) and trip. For amateur radio operators, this is critical electrical safety. Understanding this helps ensure safe electrical operation.
考试技巧
GFCI trips = current flowing from hot wires directly to ground. Think 'G'FCI = 'G'round 'F'ault 'C'urrent 'I'mbalance. GFCIs detect current imbalance (current going to ground instead of returning through neutral) and trip. Not hot to neutral (normal), not overvoltage - just current to ground.
记忆口诀
GFCI trips = current flowing from hot wires directly to ground. Think 'G'FCI = 'G'round 'F'ault. GFCIs detect current imbalance (current going to ground instead of returning through neutral) and trip. Critical electrical safety protection.
实际应用示例
A GFCI: It monitors current flow. If current flows from a hot wire directly to ground (instead of returning through neutral), the GFCI detects the imbalance and trips, disconnecting AC power. This protects against electric shock - if you touch a hot wire, current flows through you to ground, and the GFCI trips. Current to ground causes GFCI to trip.
错误选项分析
Option A: Incorrect. Current flowing from hot to neutral is normal operation - GFCI doesn't trip on normal current flow. Hot to neutral is normal. Option C: Incorrect. Overvoltage on hot wires doesn't cause GFCI to trip - GFCIs detect current imbalance, not overvoltage. Overvoltage isn't detected. Option D: Incorrect. Since A and C are not correct, 'all of the above' cannot be correct. Only current to ground causes GFCI to trip.
知识点
Ground fault circuit interrupter, GFCI, Current to ground, AC power disconnection
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.