【Weekly Topic】【Electrical Edition 20170112】
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This post was last edited by yuchenchf on 2017-1-18 at 12:41. Reward for participation: 2 Wealth. **Correct reward: 9 points. Which of the following statements is correct? ( ). A. In the TN-C-S system, the protective wire and the neutral wire are not allowed to be connected to each other again starting from the separation point. B. Metal mesh from snake pipes, insulation pipes, thin-walled steel pipes, or their outer covers can be used as grounding wires or protective wires. C. Grounding system: The neutral point of a generator or transformer is either not connected to the grounding device (insulated from the ground), or it is connected to the grounding device through devices with high resistance or high reactance; in the event of a single-phase ground fault, the short-circuit current is very small, hence this system is also known as a low-current grounding system. D. The grounding and safety design of electrical equipment should be determined reasonably based on the characteristics of the project, its scale, development plans, geological conditions, as well as operational and maintenance aspects. AD
The correct statements are (AD). A. In the TN-C-S system, the protective wire and the neutral wire are not allowed to be connected to each other again starting from the separation point. B. Metal mesh of snake tubes, insulation tubes, thin-walled steel pipes, or their outer covers can be used as grounding wires or protective wires. C. Grounding system: The neutral point of a generator or transformer is either not connected to the grounding device (insulated from the ground), or it is connected to the grounding device through specialized devices with high resistance or high reactance; in the event of a single-phase ground fault, the short-circuit current is very small, hence this system is also known as a low-current grounding system. D. The grounding and safety design of electrical equipment should be determined based on the characteristics, scale, development plans of the project, geological conditions, as well as operational and maintenance aspects