DSH 754 Screws, Creepage distance and clearance

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DSH 754 0 |5 e0 r8 v2 W+ H  E

Screws, Creepage distance and clearance 5 b4 i$ k7 A2 d, |+ }3 t8 E8 d

21.19 ' I$ x' h" a: r8 n+ Z

60745-1(ed.4) ; u# t1 P7 r, X) X

7 O9 X& `/ H' a( \3 g( Z# ?$ @Standard(s):
0 A2 V9 E2 O& X$ }% \6 q  @IEC 60745-1:2006
1 s4 b% ?: I2 C& aSub-clause(s):
- ~0 A0 F  Y. ?; p9 ?# @" ~21.19
1 H$ L# {6 K0 ?) O: ?No. Year
! ^$ v! u) y$ }* w9 _8 RDSH
754
. q! B$ g  W$ ~" e/ }. |9 N0 a8 @2010
3 ^/ |% M% e* t1 ?4 m& ~Category: TOOL Developed by: ETF 1
Subject:
Screws, Creepage
distance and clearance
1 z& l7 @; {7 r; P3 {3 jKey words:
6 Z! U& u0 J, s% a" o5 g1 [& H: c- Screws
- force
- Creepage distance and
3 p# Y+ J# Y2 s- i; N6 {clearance
6 g. O* {0 x' ]% v& X1 OApproved at the 2010 CTL
0 m7 O! o% [6 h3 D$ C4 m/ MPlenary Meeting
0 [' Y* L: C& E1 \* v1 cQuestion:
1)
“Tools shall be so designed that the protection against electric shock is not affected when
screws intended for replacement from the outside during routine servicing are replaced by
screws having a greater length.”
" S8 C# @* }. |" W$ @What screw should be used? Only the screws from equipment under test or any other
/ U) d# I' m/ ^  rpossible screw?
2)
“Compliance is checked by inserting longer screws, without appreciable force, after which
creepage distances and clearances between live parts and accessible metal parts shall not
have been reduced below the values specified in 28.1”
What force is to be applied?
4 f2 ]2 E& q% M+ S/ mDecision:
1)
The screw originally used on the equipment and any other longer screw that can be found
on the equipment is to be used.
2)
4 L4 Y* p* [/ cThe force values in Table 9 shall be applied.
( ]1 q. S$ D2 s! A; z& f0 ]1 t7 j