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本帖最后由 passagere 于 2017-6-29 05:25 编辑 ; Y$ V2 P" d- a/ P# y
sheleason 发表于 2017-6-27 18:12
1 S. M# W* x8 V2 `% B4 m借楼问一下。有款灯具 输入线是3线 里面连接的内置电源。灯具外壳是金属 但是外壳没有接地。6 S3 ]3 M6 G Z5 O8 ^ o i
。灯具的输入 ... # j' X5 f3 ^) Y* V2 o
按60598,地线没有连接到可接触的金属部件上时,可以作为II类灯具(同时满足II类结构要求)。II类灯具不需要做接地连续性测试。GND到地线上不传导绝缘失效时的危险电流,所以不需要做。
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6 @7 d% w& L/ a/ ]! U4 o; a7 bGND上到地线,是为了功能或者电磁兼容的作用,不是为了传播电流的。如果I类灯具,且PCB上的铜箔作为传输路径时(I类灯具上也有功能接地部分,不是接到PCB上就一定对trace有大电流传播要求),那是需要额外验证大电流通过能力的。路径为:地线——PCB trace——可能带电的金属部件时,trace才可能传播大电流。& V7 C/ ^. \$ a! d& C
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在60598里找到条款,按II类灯具判就可以了。+ D6 E6 \9 V$ j$ l0 P
1.2.23
* ~8 `) O! k3 v; V" N% q9 oclass II luminaire
) w. D9 W- Y; i6 |luminaire in which protection against electric shock does not rely on basic insulation only, but in8 ?8 L% a# S, G+ m2 [& D/ {
which additional safety precautions such as double insulation or reinforced insulation are! d' @9 \9 |, {0 k+ w n9 V
provided, there being no provision for protective earthing or reliance upon installation
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0 ]4 c' X# h$ \0 e1 }* M, {- dNote 3 to entry: If earthing is provided to assist starting, or for EMC reasons, but is not connected to an& b9 Q3 A9 [2 a6 N ?6 p" S
accessible metal part, the luminaire may still be deemed to be of class II. Accessible metal parts in compliance with
8 J2 R% t3 J/ Fthe appropriate IEC lamp specification and other metal parts not normally earthed and not normally accessible, L! e& m$ l0 u# q
during normal use are not regarded to be conductive parts which may cause an electric shock unless the tests of+ g e+ P; s! e: X8 j: U; R
Annex A show them to be live parts.
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从上面条款可以看出,功能接地的灯具,满足要求时可以判为I类灯具。具体判定位I还是II,看结构特点和那个更容易实现、简单。$ {0 A/ C4 S, c/ ]% {! n
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