UL250 关于电气间隙
& Q$ N! E8 U# V6.1.6 An insulating liner or barrier of fiber or similar material, employed where spacings would otherwise
+ W$ w( [" G. y, J( ~! \/ sbe less than the required values, shall be no less than 0.71 mm (0.028 inch) thick and shall be so located
: H1 |& Q2 n& d! f4 d7 nor of such material that it will not be subject to deterioration as a result of arcing., Z1 e% ], t( O3 }: e( B& P
Exception No. 1: Fiber no less than 0.3 mm (0.013 inch) thick may be used in conjunction with an air
2 h& {4 m# N/ Dspacing of no less than 50 percent of the spacing required for air alone.
3 g, W. d4 b& [. O' EException No. 2: Material having a lesser thickness may be used if it has equivalent insulating,
! P+ F6 Z7 }* Q/ u" \mechanical, and flammability properties when compared with materials in thicknesses specified above.1 W3 R( q& D _- O" l1 b* O( i
其中提到的0.71mm为绝缘厚度,但是没有提到是什么情况下。7 G# {+ l" u6 Z. D+ k; F7 s. }( @
请大家指导。 |