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这个结构要保证两个条件,即IP和接地符合标准要求。6 y- k' n9 e! L, [* `* j5 c5 t, K
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对于接地问题,首先要做防松措施,保证接地连续性,还要检测接地电阻值有没有超出标准要求0.5欧姆。
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如图片结构,想利用灯体大身与封盖之间的螺丝做接地连续,但又要保证能符合IP要求,按标准要求,接地用途的部件是不能用于其它目的。+ P8 [" Z& D4 Z2 @% p
(是不是出于成本考虑,不使用单独的接地螺丝和接地线)
2 i' [5 p1 j+ | H# T- t0 v如中间衬垫了非铜金属的又是在维修期间必须拆装的,潜在接地连续性及低电阻性将不能保证。5 z+ F2 w% G6 F. y$ V
The earthing connections shall be of low resistance.
2 Z5 }% W4 O9 B1 h: J6 L0 q; kSelf-tapping screws may be used to provide earthing continuity, provided they comply with the requirements given in 4.12.1.
/ e: v( z+ w% \$ _# w( c6 h' H- F7.2.8 Either the screw or the other part of the earth terminal shall be made of brass or other non-rusting metal or a material with a non-rusting surface and the contact surfaces shall be bare metal." u `/ l% R1 o
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