【Daily Topic】【Electrical Edition 20160927】
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This post was last edited by hesonchang214 on 2016-9-28 09:02. Reward for participation: 2 Wealth. Reward for correct answer: 9 Wealth. Regarding the metal shielding layer of single-phase power cables, it must be directly grounded. As for the normal induced voltage at any point on the metal shielding layer that is not grounded, the specified requirements are ( ). A. When no safety measures are in place to prevent arbitrary contact with the metal shielding layer, the voltage shall not exceed 50V. B. The grounding resistance value must meet the requirements for the protection and proper functioning of electrical installations, and it must remain effective over the long term. C. Protective measures must be taken to prevent damage to other metal components caused by electrochemical erosion. D. It must be able to withstand grounding fault currents and current leaks to ground, especially without suffering any damage due to heat, thermal mechanical stress, or electrical mechanical stress. Correct answers: AC
A. It must not be greater than 50V when no safety measures are in place to prevent arbitrary contact with the metal shielding layer. C. Protective measures must be taken to avoid damage to other metal components caused by electrocorrosion