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Tricity 发表于 2016-6-22 11:20:26

413.3.6 The exposed-conductive-parts of the separated circuit shall not be connected either
to the protective conductor or exposed-conductive-parts of other circuits, or to earth.

6.5 Protection by electrical separation
Electrical separation is achieved where the following conditions are met:
– basic protection is provided by basic insulation between hazardous-live-parts and exposed-conductive-parts of the separated circuit; and
– fault protection is provided
• by simple separation of the separated circuit from other circuits and earth, and
• by a protective-equipotential-bonding interconnecting exposed-conductive-parts of the separated circuit where more than one item of equipment is connected to the separated circuit. This protective-equipotential-bonding system shall not be earthed.
Intentional connection of exposed-conductive-parts to a protective earthing conductor or to an earthing conductor is not permitted.

治学以诚 发表于 2016-6-22 11:35:15

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Tricity 发表于 2016-6-22 17:53:17

治学以诚 发表于 2016-6-22 12:28
因为RA=1000欧。也比C2小无限多,C2通常是兆欧起跳。
RA与C2分C1上的电压,RA分压显然近于0。


您确定您正确理解了IEC那段话的意思么?

王老的书我虽然看得很少,就看过的而言,多数内容并非是出自他个人的意见,有些其实原本就是IEC的规定,他无非是通过一些例子解释为什么IEC这么规定。

外壳不允许人为接地的原因,我个人认为还是担心有可能引入通过PE导体传递的外部故障电压。
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查看完整版本: 隔离变压器供电的设备外壳,如果通过接地极接大地了,是否有安全风险?