【Daily Topic】【Electrical Edition 20160917】
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Participation reward: 2 Wealth. Reward for correct answer: 9 Wealth. Metal cable trays, as well as their supports and the metal cable conduits used for introducing or leading cables, must be reliably grounded (PE) or connected to the neutral conductor (PEN), and must comply with the provisions in ( ). A. The total length of metal cable trays and their supports shall be connected to the grounding (PE) or neutral (PEN) main conductors at no fewer than two points. B. Copper grounding wires shall be strung across both ends of the connection plates between ungalvanized cable trays; the minimum allowable cross-sectional area of such grounding wires is 10 mm². C. No grounding wires need to be strung across both ends of the connection plates between galvanized cable trays, but there shall be no fewer than two connection bolts with anti-loosening nuts or washers at each end of the connection plates. D. The connection plates between galvanized cable trays shall be welded together. Correct answers: AC
A. The metal cable tray and its supports must be connected to the grounding (PE) or neutral (PEN) main conductors at no fewer than two points along their entire length. C. The ends of the connection plates between galvanized cable trays shall not be bridged with grounding wires; however, there must be at least two connection bolts at each end of the connection plates, equipped with locknuts or anti-loosening washers