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在UL线路板说明(见下网址)) B4 d, W; K. M; s# l; }8 s1 ~
http://database.ul.com/cgi-bin/X ... 4637&sequence=16 y6 c) t8 i) g1 V' I
看到:
3 S6 R" n" `* N9. Voltage Rating — No voltage rating is assigned. The suitability of the base material as insulation between live-metal parts and dead-metal parts shall be determined in the end product. * z: p3 T! ?* R5 S% i& N
10. Minimum Spacing — Minimum required spacing between conductors of different potential and between these conductors and dead-metal parts. Cupping, twisting, bowing and/or warping of the board has not been investigated.
+ a, H% R% v- c7 }11. Minimum Dielectric Thickness — Minimum required dielectric/insulation thickness (distance through) between conductor layers has not been investigated regarding dielectric strength requirements in the end-product design.
- z( b& v8 i: {5 Z2 {. G可见,有关防电击的要求,如额定电压、安全距离、最小的夹层绝缘厚度要求,并未在线路板认证中进行评估。+ h( W# N e5 g) P
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UL接受非隔离电源,很可能是因为额定电压低(只有120V)。我记得UL的不接地灯具也只打1250V的耐压。 |
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