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Question
/ n& S) B: K4 f0 G1) In case of components mounted on a printed wiring board (PWB) and placed across# S5 d8 a$ v$ b2 z( d. K
(bridging) insulating distances on the PWB (e.g. providing basic or even reinforced insulation),9 a1 g% ~2 W3 ^; S' i6 I
how to deal with the different distance requirements for distances on the printed wiring
! o1 x& t J( h! zmaterial and for distances on other plastics e.g. the housing material of the component g9 i+ D4 n$ M! X
(depending on the applicable material group)?
' @# D8 c% d3 n' j1 c! Y& T5 C2) In case of components mounted on a printed wiring board (PWB) and placed across
0 a: a& [' ~" g9 K2 C+ Uinsulating distances on the PWB (e.g. providing basic or even reinforced insulation), how to5 x" [: p0 G( f$ C6 M
deal with the different distance requirements, if the material group for PWB and for the9 k2 ^. R7 a# [* l
components placed on it is not the same (e.g. PWB of material group I and relay base of2 \! z; _# m, i/ C5 }
material group IIIa)?" W/ }2 t5 W' j# \- o
Decision) H6 ^, F) p5 E/ U6 R& X1 D4 {
1) The defined reduced values for the required creepage distances relevant to printed wiring/ {% ?9 @/ e& g9 U s4 l/ q" m
material in micro-environment of pollution degrees 1 and 2 may only be applied when there
4 p$ a$ X# i; J5 nare no components bridging the investigated insulation. If components are bridging insulating
! c; \- |7 ]$ L4 s: B2 v3 `distances on the PWB, the creepage distance requirements relating to the (component)! [* L4 O6 N4 \
material representing the worst case has to be applied for the PWB also.
! Q* i0 u" N& T# p& O7 n2) In case of different material groups for the PWB and the components, again the requirement! I" a# C, v/ }1 n# r' F# S
relating to the material representing the worst case has to be used.
$ T* g4 G8 }% L& L4 p/ fRemark: A component is considered to bridge insulation on the PWB, if the surface of the- L- {5 V1 h z
component is located at a distance less than the value “X” (e.g. according to IEC 60664 series)
7 w- n4 L- V/ m4 d" xfrom the isolating PWB surface. See also enclosed drawing.4 G+ D B: s/ ]
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