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本帖最后由 passagere 于 2017-6-29 05:25 编辑 1 J! R- X" r2 ~2 K, R0 F6 c6 R
sheleason 发表于 2017-6-27 18:12
$ j* T1 Y# v& I/ {4 W/ S- K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。: D& D% i v+ c7 _: a
。灯具的输入 ...
: N+ Z1 A$ \& ^! S/ G' H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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在60598里找到条款,按II类灯具判就可以了。
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class II luminaire, y. C' L6 j8 n: G
luminaire in which protection against electric shock does not rely on basic insulation only, but in" h6 M; \$ S( K, a) p9 K N: G
which additional safety precautions such as double insulation or reinforced insulation are
! E5 ]# m+ H9 K0 e0 Oprovided, there being no provision for protective earthing or reliance upon installation& }1 `& k! b% J# g" r
conditions
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9 C( F- L* X, ]3 d. qNote 3 to entry: If earthing is provided to assist starting, or for EMC reasons, but is not connected to an! h9 y6 X) J/ A$ R) w
accessible metal part, the luminaire may still be deemed to be of class II. Accessible metal parts in compliance with3 Q9 R% M0 k3 U) r% ~. A& ~
the appropriate IEC lamp specification and other metal parts not normally earthed and not normally accessible+ P0 |4 g0 N3 d: r: |1 @( \
during normal use are not regarded to be conductive parts which may cause an electric shock unless the tests of
! k9 P1 s ^) u, [; w6 {Annex A show them to be live parts.3 C; e' j! t6 a2 H" e$ L
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8 L% x0 l/ ]. e) g* M9 j$ k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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