Coast Guard Exams
Question 528Electricity/Electronics - QMED70% to pass

A three-phase electrical system is equipped with ground detecting lamps. If one of the lamps is dark, and remains dark when the test switch is operated, what does this indicate?

AI Explanation
The correct answer is D) the dark lamp must be replaced. If one of the ground detecting lamps is dark and remains dark when the test switch is operated, it indicates that the lamp itself is defective and needs to be replaced. The darkness of the lamp does not necessarily indicate a ground in the electrical system. The ground detecting lamps are designed to illuminate when there is no ground fault, so a dark lamp suggests an issue with the lamp itself rather than the electrical system. The other answer choices do not accurately reflect the situation described in the question.