Kiểm tra & Khắc phục sự cốCâu 484 / 521
Before performing a continuity test on a cable with an ohmmeter, what condition must exist?
a.The circuit must be de-energized (no voltage present)
b.The circuit must be energized at full load
c.The conductor must be under 120 V
d.The neutral must be bonded to a driven ground rod
Giải thích
An ohmmeter/continuity function supplies its own small test voltage; applying it to a live circuit gives false readings and can damage the meter or injure you. The conductor must be de-energized and isolated. Energizing (b, c) defeats the test, and grounding a rod (d) is unrelated.
Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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