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本帖最后由 passagere 于 2017-6-29 05:25 编辑 ! N# m' r( @3 l3 d
sheleason 发表于 2017-6-27 18:12 - c* E4 |' k; }2 }1 a, |0 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。$ |6 P, ^# |! S1 r! E {3 D) A+ E
。灯具的输入 ... ) A: Y% u; g# y1 v$ E3 O0 s
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。' ^8 y9 M3 @/ x5 W5 p, L% Q& n3 y8 h
A) d2 B/ g: Q- y7 d1 J0 z在60598里找到条款,按II类灯具判就可以了。
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; e/ N1 U- u4 x: @2 c( R zclass II luminaire
e7 l- w( k- M- n. [* Cluminaire in which protection against electric shock does not rely on basic insulation only, but in
2 ^3 r g; t, Hwhich additional safety precautions such as double insulation or reinforced insulation are+ D! m0 D* t" p! K. j+ s
provided, there being no provision for protective earthing or reliance upon installation: V8 |0 d. G8 ?; N% r! ^- E7 M' c# f
conditions) K+ o& u# j, Q* j7 l/ U0 k' I
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Note 3 to entry: If earthing is provided to assist starting, or for EMC reasons, but is not connected to an7 M% J# o m- {& a1 V
accessible metal part, the luminaire may still be deemed to be of class II. Accessible metal parts in compliance with
6 d$ R: o. O: H; Gthe appropriate IEC lamp specification and other metal parts not normally earthed and not normally accessible/ J6 X" v) H8 D
during normal use are not regarded to be conductive parts which may cause an electric shock unless the tests of. _$ @0 g F% [* U- V7 j
Annex A show them to be live parts.) h/ _6 k/ N" |6 @
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# z4 d3 k* J% P9 t+ j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。9 k7 F! P y/ ^0 I& `8 ^
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