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| DSH 380
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| Affect of solder resist on Comparative Tracking Index (CTI) of Printed Wiring Boards- Y Y/ G" W- H" v6 d- A
| 2.9.3, Table 6, Condition 3+ A& s6 v2 A1 n; k9 S
| 60950(ed.2) & 60950(ed.3)
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Standard:+ Y% Y& m' F# s& z/ B
IEC 60950, 2nd and 3rd Ed.
2 K) H k+ G0 W4 G5 x2 q# v9 i, OSub clause:
5 s* u/ [" I5 k- R# D2.9.3, Table 6, condition 3$ a( \, `2 w/ l$ F
Sheet n. 380. k! z8 _1 Z. O
Page 1 (1)
7 u6 j& z: F: J% J) V& I. YSubject:4 q1 W M: {" d1 v4 ~
Affect of solder resist on$ N2 n9 E! {7 x2 N
Comparative Tracking Index (CTI)# w7 o( g; E8 g) s7 D* c1 w
of Printed Wiring Boards' s+ ?% S8 B8 u% G# f
Key words:
, s( T' i7 c7 O' V# Q ^! f2 L-comparative tracking index, H: `4 [- P% I0 |' Q
-CTI
4 J' J9 u4 u$ z8 x* E2 [-printed wiring boards# E% _+ K# j3 R; l2 z
-PWB
! [& d: K$ P+ q0 A E" \: v-solder resist
7 K+ \- _6 X/ `3 l( qDecision confirmed' D9 O- z1 x1 y' q
at CTL 38th meeting
: }0 S4 A% c! |; d% lQuestion:
& m- E) @+ V; P2 r! e9 YThe measured Comparative Tracking Index (CTI) for a printed wiring board with solder
5 H& f) n. S8 A* presist present can be different than that for the printed wiring board without the solder resist.4 s4 M* _1 D8 O; `! Q+ B" j
The creepage distances required in the standard depends upon the CTI for the printed wiring
+ q/ d6 m4 r: Yboard.
4 E7 Z, v% N: jShould the presence of solder resist on a printed wiring board be considered in determining
. {* f- {7 h2 n; g/ kthe CTI when determining the creepage distances requirements to be applied?% ]& e3 C! {: F! s9 h
Note – Clause 2.9.5 does not apply to this question because the assembled printed wiring; @* Y- _2 y2 d1 g
board is not covered with a conformal coating.% X$ G& W, O6 H8 ?' _/ Q/ K; {
Decision:( Z9 _7 F! |% ~. ?/ {3 l
Yes.# q0 X) e6 O/ V$ Q
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