【Weekly Topic】【Electrical Edition 20170111】
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Participation reward: 2 Wealth. **Correct rewards: 9 points. The metal shielding of single-phase power cables must be directly grounded. The normal induced voltage at any point on the metal shielding that is not grounded must comply with the following requirements: ( ). A. When no safety measures are in place to prevent unauthorized contact with the metal shielding, this voltage must 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 due to electrochemical corrosion. D. The system must be able to withstand grounding fault currents and current leaks to ground, especially without being damaged by heat, thermal mechanical stress, or electrical mechanical stress. Standards: A, C
A. When no safety measures are in place to prevent arbitrary contact with the metal shielding layer, the voltage shall not exceed 50V. C. Protective measures must be taken to avoid damage to other metal components caused by electrocorrosion
B. The ground resistance value must meet the requirements for the protection and proper functioning of electrical installations, and it must remain effective over the long term
The metal shielding of AC single-phase power cables must be directly grounded. The normal induced voltage at any point on the metal shielding that is not grounded must comply with the following requirements (AC). A. When no safety measures are in place to prevent arbitrary contact with the metal shielding, this voltage must not exceed 50 V. 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. The shielding must be able to withstand grounding fault currents and current leaks to ground, especially without being damaged by heat, thermal mechanical stress, or electrical mechanical stress
The metal shielding of single-phase power cables for alternating current must be directly grounded. The normal induced voltage at any point on the metal shielding that is not grounded must comply with the following requirements: (AC). A. When no safety measures are in place to prevent unauthorized contact with the metal shielding, this voltage must not exceed 50 V. 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 due to electrochemical corrosion. D. The shielding must be able to withstand grounding fault currents and current leaks to ground, especially without being damaged by heat, thermal mechanical stress, or electrical mechanical stress