美国CLASS 1 CLASS 2 CLASS 3简单说明

bill.z · 发表于 2007-12-17 23:10

NFPA 70：national electric code  2002edition 725里介绍如下：
Class 1 Circuit. The portion of the wiring system between the load side of the overcurrent device or power-limited supply and the connected equipment. The voltage and power limitations of the source are in accordance with 725.21.
Class 2 Circuit.  The portion of the wiring system between the load side of a Class 2 power source and the connected equipment. Due to its power limitations, a Class 2 circuit considers safety from a fire initiation standpoint and provides acceptable protection from electric shock.
Class 3 Circuit.  The portion of the wiring system between the load side of a Class 3 power source and the connected equipment. Due to its power limitations, a Class 3 circuit considers safety from a fire initiation standpoint. Since higher levels of voltage and current than for Class 2 are permitted, additional safeguards are specified to provide protection from an electric shock hazard that could be encountered.
725.21 class 1circuit classifications and power source requirements.
Class 1 circuits shall be classified as either class 1 power-limited circuits where they comply with the power limitations of 725.21(A) or as class 1 remote-control and signaling circuits where they are used for remote control or signaling purposes and comply with the power limitations of 725.21(B).
(A) class 1 power-limited circuits.  These circuits shall be supplied from a source that has a rated output of not more than 30 volts and 1000 volt-amperes.
(1) class 1 transformers.  Transformers used to supply power-limited class 1 circuits shall comply with article 450
(2) other class 1 power sources.
(B) Cass 1 remote-control and signaling circuits.  These circuits shall not exceed 600volts the power output of the source shall not be required to be limited

bill.z · 发表于 2009-11-24 18:53

此标准内还有哪些大家有兴趣的,请说明....

bill.z · 发表于 2009-12-9 18:58

如何评价CLASS 2的ADAPTOR?请帮忙解答,我看了标准好象很范,有点难确定;

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