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Question9 Y1 q' m' E/ X7 V1 f8 {" }
1) In case of components mounted on a printed wiring board (PWB) and placed across
# N$ D1 j3 g4 U X1 Q* U6 b(bridging) insulating distances on the PWB (e.g. providing basic or even reinforced insulation),# \2 L( L1 `2 _; X( J
how to deal with the different distance requirements for distances on the printed wiring, X) Z. l! \; u( ^! i' {2 p
material and for distances on other plastics e.g. the housing material of the component: Q* Y1 o1 N5 O6 j p, c6 q+ b
(depending on the applicable material group)?3 l9 n0 X4 E% Q: K; `" k" W# i1 Y
2) In case of components mounted on a printed wiring board (PWB) and placed across
& D. E" N8 C2 S& ]: F O. u( y& ninsulating distances on the PWB (e.g. providing basic or even reinforced insulation), how to
* e' Q; c. r( R% O& A7 t! P6 ~* }deal with the different distance requirements, if the material group for PWB and for the
" R [; K: [* N% h- E$ |# Z' Mcomponents placed on it is not the same (e.g. PWB of material group I and relay base of2 \# l5 ?7 n: ?
material group IIIa)? G9 y5 R% l, R7 C2 a! R' N: A
Decision
. G& A. A, E& O8 v" u0 J$ b/ k1) The defined reduced values for the required creepage distances relevant to printed wiring9 q+ Q2 \% S) d) k! E& k! `/ }
material in micro-environment of pollution degrees 1 and 2 may only be applied when there
! z8 _8 u+ ^0 a) ]. I* \7 }) xare no components bridging the investigated insulation. If components are bridging insulating
0 e! `# |- D1 H2 Udistances on the PWB, the creepage distance requirements relating to the (component)
9 T5 J" B8 P' dmaterial representing the worst case has to be applied for the PWB also.3 x$ p) |7 O- n
2) In case of different material groups for the PWB and the components, again the requirement
5 x2 j4 S; f* K/ E& F, W9 ^+ G* Grelating to the material representing the worst case has to be used." {- u/ v, v8 s6 f; y5 y; K( j* K5 `
Remark: A component is considered to bridge insulation on the PWB, if the surface of the
: R# a' s+ U& Q5 v7 J* h4 Ycomponent is located at a distance less than the value “X” (e.g. according to IEC 60664 series)
1 b/ k: ^/ J5 z. S$ _7 J: @from the isolating PWB surface. See also enclosed drawing.
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