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Earthing
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香港接地系統有用 TT，TN-C，TN-S，TN-C-S，IT等，如村屋等小電流用戶用 TT，大樓與工業等大電流用戶用 TN-S，TN-C 與 TN-C-S 係電力公司配電時用既，IT 係高壓電既接地系統，爲了防止太大既短路電流在發電端既中線接地須加一個高阻坑電阻，也可以用液體電阻。 註解： 第一個字眼 T = 將發電端既中線直接接地。 I = 將發電端既中線經過高阻坑電阻接地。 第二個字眼 T = 將用戶端既電器用具既鐡殼直接接地，與發電端接地冇直接關係，短路電流低。 N = 將用戶端既電器用具既鐡殼直接與發電端既接地接埋一齊，短路電流高。 第三與第四個字眼 C = 中線與接地線同一導線。 S = 中線與接地線分開導線。 The first letter indicates the type of supply earthing. T - indicates that one or more points of the Supply are directly earthed (for example, the earthed neutral at the transformer). I - indicates either that the supply system is not earthed at all, or that the earthing includes a deliberately-inserted impedance, the purpose of which is to limit fault current. This method is not used for public supplies in the UK. The second letter indicates the earthing arrangement in the installation. T - all exposed conductive metalwork is connected directly to earth. N - all exposed conductive metalwork is connected directly to an earthed supply conductor provided by the Electricity Supply Company. The third and fourth letters indicate the arrangement of the earthed supply conductor system. S - neutral and earth conductor systems are quite separate. C - neutral and earth are combined into a single conductor. 請參考下圖： 圖片參考：http://www.tlc-direct.co.uk/Figures/5.4b.gif 圖片參考：http://www.tlc-direct.co.uk/Figures/5.5b.gif 圖片參考：http://www.tlc-direct.co.uk/Figures/5.6b.gif 2009-02-05 07:53:30 補充： 更正 短路電流低改爲 = 接地故障短路電流低
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Earthing
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此文章來自奇摩知識+如有不便請留言告知
什麼是 IT,TT,TN-C,TN-S,TN-C-S 接地系統? 彼此有何不同?香港係咪TT??最佳解答:
香港接地系統有用 TT，TN-C，TN-S，TN-C-S，IT等，如村屋等小電流用戶用 TT，大樓與工業等大電流用戶用 TN-S，TN-C 與 TN-C-S 係電力公司配電時用既，IT 係高壓電既接地系統，爲了防止太大既短路電流在發電端既中線接地須加一個高阻坑電阻，也可以用液體電阻。 註解： 第一個字眼 T = 將發電端既中線直接接地。 I = 將發電端既中線經過高阻坑電阻接地。 第二個字眼 T = 將用戶端既電器用具既鐡殼直接接地，與發電端接地冇直接關係，短路電流低。 N = 將用戶端既電器用具既鐡殼直接與發電端既接地接埋一齊，短路電流高。 第三與第四個字眼 C = 中線與接地線同一導線。 S = 中線與接地線分開導線。 The first letter indicates the type of supply earthing. T - indicates that one or more points of the Supply are directly earthed (for example, the earthed neutral at the transformer). I - indicates either that the supply system is not earthed at all, or that the earthing includes a deliberately-inserted impedance, the purpose of which is to limit fault current. This method is not used for public supplies in the UK. The second letter indicates the earthing arrangement in the installation. T - all exposed conductive metalwork is connected directly to earth. N - all exposed conductive metalwork is connected directly to an earthed supply conductor provided by the Electricity Supply Company. The third and fourth letters indicate the arrangement of the earthed supply conductor system. S - neutral and earth conductor systems are quite separate. C - neutral and earth are combined into a single conductor. 請參考下圖： 圖片參考：http://www.tlc-direct.co.uk/Figures/5.4b.gif 圖片參考：http://www.tlc-direct.co.uk/Figures/5.5b.gif 圖片參考：http://www.tlc-direct.co.uk/Figures/5.6b.gif 2009-02-05 07:53:30 補充： 更正 短路電流低改爲 = 接地故障短路電流低
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