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本帖最后由 passagere 于 2017-6-29 05:25 编辑 , E2 e7 U, B" c
sheleason 发表于 2017-6-27 18:12
0 r W6 T0 k- ^8 J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。7 G2 C, Q! R# F3 \" C- r$ Q
。灯具的输入 ...
+ j; J* }7 u& o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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9 c5 ?+ v/ B' Y% j( E+ _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。$ x7 c- @+ H; l
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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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+ |1 f" ~2 M, L9 Eclass II luminaire
3 z8 l8 w- {9 V( p ]luminaire in which protection against electric shock does not rely on basic insulation only, but in
. w! c/ e, u b; I! x' \1 ywhich additional safety precautions such as double insulation or reinforced insulation are
+ ]( L/ Y& O+ |+ u* l6 C" L; ?provided, there being no provision for protective earthing or reliance upon installation
+ Y0 K) u! r* Sconditions+ Q8 f2 V/ B$ k5 r0 O; ?
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7 j4 P& h- h s- y9 {Note 3 to entry: If earthing is provided to assist starting, or for EMC reasons, but is not connected to an
5 D6 b! H% o d2 J& A; {0 x, P; Uaccessible metal part, the luminaire may still be deemed to be of class II. Accessible metal parts in compliance with
L! P- F5 K9 i0 s6 y, V: _the appropriate IEC lamp specification and other metal parts not normally earthed and not normally accessible
/ i4 Y5 K- I1 Kduring normal use are not regarded to be conductive parts which may cause an electric shock unless the tests of
& m% f( r. }; i8 b2 C" l, {+ IAnnex A show them to be live parts.
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% c0 `; k5 {6 n& {3 t: N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。0 O9 L& b( v; F6 w( f, P% A
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