TN-C-S中的一句话

Mr.Deng

对于这个问题，尺总分析的比较透切了。

尺短寸长

扩展到相距100米以外的A、B两建筑，远不是伸臂范围的问题了。A采用TT，接地后不立即切除，无论B采用TN-C还是TN-S，PEN、N、PE导线都会把中性点对大地零点电位带入到B建筑室内来。如果检修不断N线，不断PEN线（做总等与重复接地，仍然不可以消除与大地电位零点之间的电压），检修就存在电击风险。
治学以诚 发表于 2013-6-8 07:20

                               
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411.4.1 In TN systems the integrity of the earthing of the installation depends on the reliable and effective connection of the PEN or PE conductors to earth. Where the earthing is provided from a public or other supply system, compliance with the necessary conditions external to the installation is the responsibility of the supply network operator.

411.4.3 In fixed installations, a single conductor may serve both as a protective conductor and as a neutral conductor (PEN conductor) provided that the requirements of 543.4 of IEC 60364-5-54 are satisfied. No switching or isolating device shall be inserted in the PEN conductor.

尺短寸长

NOTE 1 Examples of conditions include:
− the PEN is connected to earth at a number of points and is installed in such a way as to minimize the risk of a
break in the PEN conductor;
− RB/RE ≤ 50/(U0 – 50)
where
RB is the earth electrode resistance, in ohms, of all earth electrodes in parallel;
RE is the minimum contact resistance with earth, in ohms, of extraneous-conductive-parts not connected to a
protective conductor, through which a fault between line and earth may occur;
Uo is the nominal a.c. r.m.s. voltage to earth, in volts.
NOTE 2 In Germany compliance with condition RB/RE ≤ 50 / (Uo – 50) is compulsory for the supply network
operator.

尺短寸长

NOTE 1 Examples of conditions include:
− the PEN is connected to earth at a number of points and is installed in such a way as to minimize the risk of a break in the PEN conductor;
− RB/RE ≤ 50/(U0 – 50)
where
RB is the earth electrode resistance, in ohms, of all earth electrodes in parallel;
RE is the minimum contact resistance with earth, in ohms, of extraneous-conductive-parts not connected to a protective conductor, through which a fault between line and earth may occur;
Uo is the nominal a.c. r.m.s. voltage to earth, in volts.

NOTE 2 In Germany compliance with condition RB/RE ≤ 50 / (Uo – 50) is compulsory for the supply network operator.

尺短寸长

狗屁，你给个电路，证明一下，PEN，重复接地与不重复接地，两者之间的危险性不就完了吗
治学以诚 发表于 2013-6-9 16:59

                               
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“IEC_60364-4-41：2005”＝老诚破口大骂的 狗屁 ？

尺短寸长

老诚自己画的图，早已经证明了的。{:1_274:}

尺短寸长

德国供电公司是“狗屁”？

尺短寸长

……
如TT系统，N线接地了，就不能再允许相线接地了。
治学以诚 发表于 2013-6-9 17:13

                               
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如TT系统，N线接地了，就不能再允许相线接地了。

好的。
那么，如TN系统，N线接地了，就允许相线接地了?