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本帖最后由 passagere 于 2017-6-29 05:25 编辑 & @% I1 s% Z" Z l/ j
sheleason 发表于 2017-6-27 18:12
% O, Q4 r4 T+ ~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。
" H9 l8 |, t6 o5 x。灯具的输入 ... ) G( R0 T4 H% J0 m E. }
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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# P* Q" x. Z4 z' ~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。! r! @1 k/ ]' b: O
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在60598里找到条款,按II类灯具判就可以了。3 K% L, g/ V; C) Z; l$ @8 R
1.2.233 S n9 _" M" Q4 F! B( W2 Y2 m
class II luminaire
+ M0 W- z% R$ J5 l; ?2 `luminaire in which protection against electric shock does not rely on basic insulation only, but in1 }- X# @$ _" U$ W7 ~* F
which additional safety precautions such as double insulation or reinforced insulation are7 X& A4 l! K& Q$ M
provided, there being no provision for protective earthing or reliance upon installation
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- F# Z2 P) F) q$ M$ fNote 3 to entry: If earthing is provided to assist starting, or for EMC reasons, but is not connected to an
! u5 s X+ H. L! I* P+ k# Zaccessible metal part, the luminaire may still be deemed to be of class II. Accessible metal parts in compliance with' h8 z' u E3 W( z- S1 r
the appropriate IEC lamp specification and other metal parts not normally earthed and not normally accessible4 [% W% H- b) s* u. C) y8 R
during normal use are not regarded to be conductive parts which may cause an electric shock unless the tests of
) ]7 i' u/ e3 D% iAnnex A show them to be live parts.1 l) x5 ^, e0 c$ O1 B3 T& ^! I2 E
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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。$ m! O: u- ~" R0 f1 D& I3 f
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