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Question0 K, v/ T5 W- K: y( [& P4 W
1) In case of components mounted on a printed wiring board (PWB) and placed across
. s6 M+ @3 X: F8 F(bridging) insulating distances on the PWB (e.g. providing basic or even reinforced insulation),
% a+ x9 t* F+ P; K) ~how to deal with the different distance requirements for distances on the printed wiring+ L1 f# p* B; U; l
material and for distances on other plastics e.g. the housing material of the component
l$ \, R* v. a+ [(depending on the applicable material group)?
- ~7 |& G$ }8 {* h2) In case of components mounted on a printed wiring board (PWB) and placed across& q, ~3 Y" O3 [7 `8 Q
insulating distances on the PWB (e.g. providing basic or even reinforced insulation), how to/ w3 l6 ?! p# ^! L# q. ]1 H; e
deal with the different distance requirements, if the material group for PWB and for the: x t, L! W; o* h
components placed on it is not the same (e.g. PWB of material group I and relay base of
) X( B" G: L$ a! Pmaterial group IIIa)? c5 _ j' ~, t1 z! N% |2 T
Decision
& \" H: F9 r5 n5 L' z; ~1) The defined reduced values for the required creepage distances relevant to printed wiring
& u2 q) K3 p9 c, a+ Q. y6 p! i& z; lmaterial in micro-environment of pollution degrees 1 and 2 may only be applied when there0 W( Q( g0 e; Q* J1 u$ h% P
are no components bridging the investigated insulation. If components are bridging insulating* M, M5 q7 N* b; d; m, S1 `
distances on the PWB, the creepage distance requirements relating to the (component)* q- |3 T; u0 \
material representing the worst case has to be applied for the PWB also.1 b7 t: j6 a" r: m9 G
2) In case of different material groups for the PWB and the components, again the requirement- E3 \& m5 _( u3 v. B7 O- [
relating to the material representing the worst case has to be used.
3 p4 c4 ~% ?$ `% }) S! ZRemark: A component is considered to bridge insulation on the PWB, if the surface of the
8 p9 `: v' ~& ~$ |: xcomponent is located at a distance less than the value “X” (e.g. according to IEC 60664 series)* n. k6 s8 _+ Q+ O0 d- F" d
from the isolating PWB surface. See also enclosed drawing.
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! E9 A# p5 v9 u& Z' h4 f' A3 Y, F7 z, \7 I! F3 Q
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