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Question0 @& }; H0 E9 l# ]: I) s0 y
1) In case of components mounted on a printed wiring board (PWB) and placed across- d! j1 }* l0 m
(bridging) insulating distances on the PWB (e.g. providing basic or even reinforced insulation),
7 T0 n8 z$ W6 w6 T/ e4 d8 `; `/ rhow to deal with the different distance requirements for distances on the printed wiring
1 E/ g0 K R: Y5 U; k. Smaterial and for distances on other plastics e.g. the housing material of the component- K/ v8 ^9 F6 t2 G- B9 ^
(depending on the applicable material group)?
1 N. \3 q0 I) E) {" P" j2) In case of components mounted on a printed wiring board (PWB) and placed across8 M7 ~. e0 {3 M9 H! K
insulating distances on the PWB (e.g. providing basic or even reinforced insulation), how to3 }8 ]( r. P/ z+ U; M$ h5 `
deal with the different distance requirements, if the material group for PWB and for the
. W! @: d, |7 v7 k3 R t9 |$ o2 K" fcomponents placed on it is not the same (e.g. PWB of material group I and relay base of
1 B' H2 X( a1 b, \8 H: _ rmaterial group IIIa)?& R- k: \$ k! g8 `1 p5 ~
Decision
4 x- W& @4 g1 n$ w* H* t5 [1) The defined reduced values for the required creepage distances relevant to printed wiring
+ X8 \1 V" f t6 l6 Vmaterial in micro-environment of pollution degrees 1 and 2 may only be applied when there
- a6 m2 s# e, o/ A2 V, jare no components bridging the investigated insulation. If components are bridging insulating
3 u6 @- P6 p6 O: q, jdistances on the PWB, the creepage distance requirements relating to the (component)) d( O, q* A5 w$ Q
material representing the worst case has to be applied for the PWB also.
% v8 u7 ]/ A- n: q2) In case of different material groups for the PWB and the components, again the requirement
/ X) \% F! ] l' Z0 v- T7 S, ?relating to the material representing the worst case has to be used.0 V- f/ S! G7 [' [9 J& x% E
Remark: A component is considered to bridge insulation on the PWB, if the surface of the# P, O- [0 b9 ^! K6 E& }/ }5 ~
component is located at a distance less than the value “X” (e.g. according to IEC 60664 series)" X; v) B. C+ X) @
from the isolating PWB surface. See also enclosed drawing.9 k+ K6 [7 ] h
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