Kiểm tra & Khắc phục sự cốCâu 499 / 521
Before touching conductors you believe are de-energized, what is the safest way to verify your voltage tester is trustworthy?
a.Assume it works if the battery indicator is on
b.Test only the conductors in question once
c.Shake the meter and listen for the beep
d.Prove the tester on a known-live source, test the de-energized conductors, then re-prove it on the known-live source (live-dead-live)
Giải thích
The live-dead-live method proves the tester reads voltage on a known source before and after checking the suspect conductors, confirming the meter didn't fail mid-test. A battery light (a) or a single test (b) does not prove the tester actually works, and shaking it (c) proves nothing.
Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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