UL250 关于电气间隙4 T! w" V- |0 q4 }% C
6.1.6 An insulating liner or barrier of fiber or similar material, employed where spacings would otherwise
% ~5 b7 H" W& ]' obe less than the required values, shall be no less than 0.71 mm (0.028 inch) thick and shall be so located; F* a" E+ Q* [
or of such material that it will not be subject to deterioration as a result of arcing." Q0 Y) s1 F+ }% z; a. E) R" M
Exception No. 1: Fiber no less than 0.3 mm (0.013 inch) thick may be used in conjunction with an air
& a0 O$ j" w, i8 {& @% Q5 X6 wspacing of no less than 50 percent of the spacing required for air alone.; W, Q; z$ M7 X. y
Exception No. 2: Material having a lesser thickness may be used if it has equivalent insulating,) g1 [4 t: p5 U+ p7 X
mechanical, and flammability properties when compared with materials in thicknesses specified above.1 A! L9 Y2 ~9 C5 X" @/ x2 z' P
其中提到的0.71mm为绝缘厚度,但是没有提到是什么情况下。" W; `5 K) K* c2 P1 x8 B
请大家指导。 |