国内专家提问IEC专家(中文版).doc

PROBLEMS IEC 60364 - 4 – 41 GB16895.21 Protective equipotential bonding 保护等电位联结 According to IEC61140 5.2.5 and IEC 60364-4-41 411.1, shall protective equipotential bonding be provided for outdoor TN and TT system with automatic disconnection of supply? 根据IEC61140 （GB/T17045）5.2.5及IEC 60364-4-41 （GB16895.21）411.1，应为带有自动断电保护的户外TN和TT系统，提供保护等电位联结吗？ What kind of earthing systems commonly used for external lightings (including street lighting) in foreign countries? 在国外，外部照明（包括路灯）一般使用哪类接地系统？ The permissible maximum disconnection time 5 s or 1 s for circuits defined by IEC 60364-4-41 411.3.2.3 and 411.3.2.4, in case of without protective equipotential bonding, can it ensure the protection against electric shock? IEC 60364-4-41（GB16895.21） 411.3.2.3 和411.3.2.4规定，允许最大断电时间5 s 或1 s，在没有保护等电位联结的情况下，能确保防电击吗？ Wherever the steel reinforcement of concrete structures to be considered as external conductive parts, shall it be welded or it may be wrapped is allowable for protective equipotential bonding purpose? What about for down conductor of lightning protection system? 将混凝土结构加强钢筋作为外部可导电部分考虑的任何情况下，应将其作为保护等电位联结进行焊接或缠绕吗？防雷系统的引下导体是怎样的？ For building floors without steel reinforcement, shall it to be provided additional protective equipotential bonding? (e.g. mesh) 没有钢筋的建筑楼层，应提供附加保护等电位联结吗？（比如：金属网） Fault loop impedance ZS 故障回路阻抗ZS Fault loop impedance ZS of LV system is calculated by fundamental sequence impedance or by zero sequence impedance? 低压系统的故障回路阻抗，是按基本阻抗还是按0区阻抗计算？ TT system 解释：根据IEC 60364-4-41（GB16895.21）411.5.1，由相同的保护电器予以保护所有外露导电部分，应通过保护导体连接至他们的公共接地极。 Clarify: In outdoor or wet locations, RA ≤ UL./IDn, conventional touch voltage UL ≤ 25 V. 澄清：户内或潮湿场所，RA ≤ UL./IDn, 转换为接触电压UL ≤ 25 V. IT system Explain: Why isolation device shall be provided for neutral conductor of IT system with isolated neutral? 解释：为何中性线隔离的IT系统，仍然要在中性线上安装隔离电器？several ten kΩ or 0.5 MΩ) 绝缘监测电器（IMD）的绝缘电阻的典型动作值范围是多少？– 4 – 42 GB16895.2 Protection against thermal effects 热效应保护 Explanation: clause 422.3.9 for