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Question. `/ ?: \* S4 T3 o, @
1) In case of components mounted on a printed wiring board (PWB) and placed across0 v" f2 S4 Q0 T* G* v% ?# f5 \
(bridging) insulating distances on the PWB (e.g. providing basic or even reinforced insulation),
( Q' A$ ^- r6 q( ^6 v; H. n7 I6 ahow to deal with the different distance requirements for distances on the printed wiring
7 |7 P$ ?( c) K* j4 [/ Amaterial and for distances on other plastics e.g. the housing material of the component
3 X; F' f: b$ i4 h* T& w% T(depending on the applicable material group)?
* z0 p1 i2 E2 f2 D2) In case of components mounted on a printed wiring board (PWB) and placed across
# y) f7 n$ p+ }insulating distances on the PWB (e.g. providing basic or even reinforced insulation), how to, l) x7 H7 q$ Z
deal with the different distance requirements, if the material group for PWB and for the2 }& v6 c( G$ e' c, k
components placed on it is not the same (e.g. PWB of material group I and relay base of
! U) w! t; B1 o. ~, t+ A& ]3 _: Ematerial group IIIa)?: A+ P0 k% D$ e P
Decision
5 u. }( R4 g4 {5 _1) The defined reduced values for the required creepage distances relevant to printed wiring
2 e! n9 z {+ P0 Q4 imaterial in micro-environment of pollution degrees 1 and 2 may only be applied when there
3 c1 O* H3 }. r& \are no components bridging the investigated insulation. If components are bridging insulating
8 l7 ?2 V' Y9 m5 S) W3 Q1 mdistances on the PWB, the creepage distance requirements relating to the (component)
6 j! M) v( n/ Pmaterial representing the worst case has to be applied for the PWB also.
7 o U4 j0 r0 @& c8 W3 l- A2) In case of different material groups for the PWB and the components, again the requirement
; H0 Q" }% Y" k: r) R/ |relating to the material representing the worst case has to be used.1 O1 D; O8 R9 r& m2 F& X6 Z% J
Remark: A component is considered to bridge insulation on the PWB, if the surface of the- y! e3 a0 d s. ~* L; m, b* o: p' T
component is located at a distance less than the value “X” (e.g. according to IEC 60664 series)5 V/ m* u/ ]4 Z; N& c
from the isolating PWB surface. See also enclosed drawing." t" b* q) i% H9 Y) M# z
) u2 s: g9 H8 O* _$ c: c
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