Kiểm tra & Khắc phục sự cốCâu 485 / 521
A plug-in receptacle tester shows its 'hot/neutral reversed' indication at a 120 V outlet. What does this mean and what is the fix?
a.The equipment ground is open; drive a new ground rod
b.The receptacle is fine; the tester is faulty
c.The hot and neutral conductors are swapped at the receptacle terminals; reconnect the ungrounded (hot) conductor to the brass screw and the neutral to the silver screw
d.The voltage is too high; install a buck transformer
Giải thích
Reversed polarity means the ungrounded (hot) conductor is landed on the neutral (silver) terminal and vice-versa, leaving the device energized through the neutral side. Correct it by moving the hot to the brass screw and neutral to the silver screw. It is a wiring error, not an open ground (a) or over-voltage (d).
Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
- You will take voltage measurements at the line terminals of a 240 V main service panel. What minimum measurement category (CAT) rating should your meter and leads carry for this location?
- A 120 V branch circuit supplies a load drawing 1,500 W. What current does the load draw?
- Before performing a continuity test on a cable with an ohmmeter, what condition must exist?
- On a 120/240 V multiwire branch circuit, the shared neutral becomes open. What symptom is most characteristic?
- You test a 480 V motor with a 500 V megohmmeter and read 0.4 megohms. Using the common one-megohm-per-kilovolt-plus-one-megohm minimum guideline, is the insulation acceptable?
- Which instrument lets you measure the current in a single energized conductor without disconnecting or breaking into the circuit?
Cập nhật gần nhất: · quy trình kiểm tra
Đội Ngũ Biên Tập PrepPass · Đối chiếu với California CSLB C-10 Electrical Trade Examination · Quy trình kiểm tra