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Question
1 f8 e8 d4 d# R% A! Y1) In case of components mounted on a printed wiring board (PWB) and placed across [& ?5 | \' K* C
(bridging) insulating distances on the PWB (e.g. providing basic or even reinforced insulation),
& a& H: M( M+ t- n: s% i2 Xhow to deal with the different distance requirements for distances on the printed wiring9 X. _ x/ j, ^( o* q
material and for distances on other plastics e.g. the housing material of the component
4 M6 v8 Y+ O" r4 o0 N3 V! w7 C(depending on the applicable material group)?
. |4 g; l6 l* u4 I n, p2) In case of components mounted on a printed wiring board (PWB) and placed across# a" K) O* T( q3 Y2 V/ i3 F5 j
insulating distances on the PWB (e.g. providing basic or even reinforced insulation), how to; ]. t3 _/ v0 A p# {4 r* _' ]% F
deal with the different distance requirements, if the material group for PWB and for the1 o+ \0 }7 h5 ]1 u: @% x$ K8 ~
components placed on it is not the same (e.g. PWB of material group I and relay base of
6 d" h4 ~8 l7 W5 k& g6 Tmaterial group IIIa)?
3 G ~/ `" x3 y' ]9 sDecision4 [% Y/ `" d3 _4 `2 B* ~
1) The defined reduced values for the required creepage distances relevant to printed wiring% _2 {, M/ a# a# [* X% @7 q- n# T, ~
material in micro-environment of pollution degrees 1 and 2 may only be applied when there- P' B; n8 m. q. U( A+ l7 s
are no components bridging the investigated insulation. If components are bridging insulating
- E3 s2 {6 G, ~distances on the PWB, the creepage distance requirements relating to the (component)4 }+ m1 ^- B& u" n1 u
material representing the worst case has to be applied for the PWB also. j% ]1 p% K! |" m% D7 ]6 d% o ^
2) In case of different material groups for the PWB and the components, again the requirement
- ]% N% b& s* A( Mrelating to the material representing the worst case has to be used.3 C, a. U: j2 s( c! \" g) C2 `7 N
Remark: A component is considered to bridge insulation on the PWB, if the surface of the: x: K+ U! b9 k
component is located at a distance less than the value “X” (e.g. according to IEC 60664 series)* W$ N6 J( F9 P9 G* ~+ T
from the isolating PWB surface. See also enclosed drawing.; ?4 e' I* m, l0 s# H0 _) B
9 m6 `) S6 c# N4 A1 p/ A
4 {& S8 [1 c" K( B* L. j2 X8 c7 Q9 ]
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