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本帖最后由 passagere 于 2017-6-29 05:25 编辑 - n, R$ f! B3 y0 ^6 t$ i0 Z
sheleason 发表于 2017-6-27 18:12
! @* h) S5 l! Z, 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。& e$ B$ A2 t0 b$ v
。灯具的输入 ...
* k2 k6 [0 C; D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。1 B; T: m7 I7 Y# t6 N/ _
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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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在60598里找到条款,按II类灯具判就可以了。
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& C5 W6 n* @$ Qclass II luminaire1 h( k6 G/ ]8 s4 i1 O
luminaire in which protection against electric shock does not rely on basic insulation only, but in
* O2 ]6 ?) L6 K- Q7 Zwhich additional safety precautions such as double insulation or reinforced insulation are0 M9 I: M0 k0 \0 M3 q$ ~6 k: L3 ~: q
provided, there being no provision for protective earthing or reliance upon installation
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Note 3 to entry: If earthing is provided to assist starting, or for EMC reasons, but is not connected to an; H: [3 ` d B U) ?
accessible metal part, the luminaire may still be deemed to be of class II. Accessible metal parts in compliance with
1 j; u8 ~$ f& F3 o7 [- Tthe appropriate IEC lamp specification and other metal parts not normally earthed and not normally accessible
$ x; { k& U. B- Z* a0 Y- Cduring normal use are not regarded to be conductive parts which may cause an electric shock unless the tests of: \, h. J3 A7 i7 Y4 X ^7 f
Annex A show them to be live parts.
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: B% P0 q$ B* e6 r' S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。7 x9 g8 i& y F
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