UL250 关于电气间隙
! [4 z0 Q1 q; I, Z' k$ @6.1.6 An insulating liner or barrier of fiber or similar material, employed where spacings would otherwise
* Y( t6 J8 K c8 ]9 O7 Fbe less than the required values, shall be no less than 0.71 mm (0.028 inch) thick and shall be so located0 I. D' r( P7 |0 B" D3 ?. C/ |6 I9 _
or of such material that it will not be subject to deterioration as a result of arcing.' f- w) L$ s0 I1 `
Exception No. 1: Fiber no less than 0.3 mm (0.013 inch) thick may be used in conjunction with an air
; V: x+ i0 S/ A5 ~5 Qspacing of no less than 50 percent of the spacing required for air alone.
* [/ w1 g, G% OException No. 2: Material having a lesser thickness may be used if it has equivalent insulating,& {( L6 j/ J9 X
mechanical, and flammability properties when compared with materials in thicknesses specified above.
) f: ]+ b2 D+ }6 k其中提到的0.71mm为绝缘厚度,但是没有提到是什么情况下。
6 m- h+ p& h# J请大家指导。 |