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发表于 2013-5-31 15:05:25
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文章中提出水泥封装接地体的做法,在NEC中,这是辅助接地手段,不能作为主接地极使用。
即可以有,也可以无 ...
治学以诚 发表于 2013-5-24 10:56
王老说的,水泥封装接地体的做法也没错啊,IEC条文和附录就是这样的。顺着文章留的页码。。。王老文章里说的哪里有错呢???
IEC 60364-5-54:2011 Part 5-54:Selection and erection of electrical equipment – Earthing arrangements and protective conductors
542.2.3 The following are examples of earth electrodes which may be used:
– concrete-embedded foundation earth electrode;
NOTE For more information see Annex C.
– soil-embedded foundation earth electrode;
– metallic electrode embedded directly in soil vertically or horizontally (e.g. rods, wires, tapes, pipes or plates);
– metal sheath and other metal coverings of cables according to local conditions or
requirements;
– other suitable underground metalwork (e.g. pipes) according to local conditions or
requirements;
– welded metal reinforcement of concrete (except pre-stressed concrete) embedded in the earth.
附录C
Annex C
The production of a concrete-embedded foundation earth electrode during the erection of the
building may be an economical solution to obtain a good earth electrode of long standing
because
– it does not necessitate additional excavation works,
– it is erected at a depth which is normally free from negative influences resulting from
seasonal weather conditions,
– it provides a good contact with the soil,
– it extends over practically all of the building’s foundation surface and results in the
minimum earth electrode impedance which can be obtained with this surface,
– it provides an optimal earthing arrangement for lightning protection system purposes, and
– from the beginning of the erection of the building, it can be used as an earth electrode for the electrical installation of the construction site.
Besides its earthing effect, the concrete-embedded foundation earth electrode provides a good basis for the main protective bonding. |
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