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本帖最后由 passagere 于 2017-6-29 05:25 编辑
, a! T f. U, D4 S5 H+ k& T2 ]0 P" [sheleason 发表于 2017-6-27 18:12 7 t; g! j% ]& D$ u6 f
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。/ v% A. g- `2 s& C- I' `: F$ N& T
。灯具的输入 ...
, L, B7 [% c' q u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。* r' D( ^9 _0 W1 I' b
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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。3 f: g) n y2 U5 m" p
! b# x5 Q" Y* _) m, q9 P- K在60598里找到条款,按II类灯具判就可以了。
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b/ @# _& k. J) _$ B3 iclass II luminaire
; \, }, V( V3 m: B1 ?; R2 Bluminaire in which protection against electric shock does not rely on basic insulation only, but in
R2 Q9 ~- {! P/ _6 {5 pwhich additional safety precautions such as double insulation or reinforced insulation are
. m) Y# U5 _ u# \/ M* t- T4 n7 Oprovided, there being no provision for protective earthing or reliance upon installation
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$ k( \, a9 ^" u' N" C' oNote 3 to entry: If earthing is provided to assist starting, or for EMC reasons, but is not connected to an; J, M( |- U4 z+ D9 y2 O
accessible metal part, the luminaire may still be deemed to be of class II. Accessible metal parts in compliance with
; m3 I$ e1 W0 Y& h& Uthe appropriate IEC lamp specification and other metal parts not normally earthed and not normally accessible
+ s: F) L t9 v- Qduring normal use are not regarded to be conductive parts which may cause an electric shock unless the tests of
3 S; b% U* X2 f G9 L2 BAnnex A show them to be live parts.9 l* _: f! R! }8 `
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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。
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