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本帖最后由 passagere 于 2017-6-29 05:25 编辑 2 S5 x- P, A. {
sheleason 发表于 2017-6-27 18:12 ! r' x. P, [( P* m# h8 R
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。) g% o1 e+ R$ _) z M6 J0 u0 @$ |
。灯具的输入 ...
6 P+ x! w; n# f; T) L; t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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; _$ k# T& {& q( b5 i0 C6 C2 [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。% S' W4 j9 `: _% n$ v' ~8 U7 I$ `/ v
; u3 g, A( f# _* K6 b( J, e& A" C& D在60598里找到条款,按II类灯具判就可以了。) ?6 O/ ~2 Z2 _
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) G4 N1 k+ T: x, q; O% i4 ]1 I Rclass II luminaire
. N' d- f. G0 E6 vluminaire in which protection against electric shock does not rely on basic insulation only, but in7 [; w% n& S N- W
which additional safety precautions such as double insulation or reinforced insulation are
- o2 F9 O& D: n$ c5 `7 Oprovided, there being no provision for protective earthing or reliance upon installation
D+ m- n/ ~8 t* [7 i- Wconditions
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+ K1 }0 i) T* C e3 T- jNote 3 to entry: If earthing is provided to assist starting, or for EMC reasons, but is not connected to an* p$ G% h; L6 z+ o! m
accessible metal part, the luminaire may still be deemed to be of class II. Accessible metal parts in compliance with/ `$ k. y" M# T! l! l
the appropriate IEC lamp specification and other metal parts not normally earthed and not normally accessible) _0 j, R' c8 Q( q0 v# I
during normal use are not regarded to be conductive parts which may cause an electric shock unless the tests of
7 M6 ]' f1 \- C9 U4 _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。
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