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本帖最后由 passagere 于 2017-6-29 05:25 编辑 # z0 K) v: |- a; U2 u& a
sheleason 发表于 2017-6-27 18:12 - d2 J0 N; O9 a
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。; J6 u t( a8 y0 b$ ^
。灯具的输入 ... - a2 ]7 n9 y/ ~/ M( j ?1 g
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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GND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。
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3 w$ P! ?) E0 Y4 C0 O在60598里找到条款,按II类灯具判就可以了。, P4 H B9 u+ I4 F: t0 W
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class II luminaire
' [6 m" l- \: U$ nluminaire in which protection against electric shock does not rely on basic insulation only, but in! u7 T7 t: c9 _* Z+ U
which additional safety precautions such as double insulation or reinforced insulation are
) ^& T( Z! ^/ x+ C3 kprovided, there being no provision for protective earthing or reliance upon installation3 w3 K5 e) f6 f
conditions
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! q0 r5 x7 \3 S7 l+ p8 PNote 3 to entry: If earthing is provided to assist starting, or for EMC reasons, but is not connected to an# p# C4 } o9 _) p3 t2 q: P$ d
accessible metal part, the luminaire may still be deemed to be of class II. Accessible metal parts in compliance with" q- h; G; R( Q% u
the appropriate IEC lamp specification and other metal parts not normally earthed and not normally accessible1 {1 _& a* b* t' Z" y, z/ y
during normal use are not regarded to be conductive parts which may cause an electric shock unless the tests of+ z& ~1 \" X. C: G
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。/ W: c6 ?5 Z3 W2 Q! k! n
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