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| DSH 754! n& W. V5 @1 z6 p. @8 ^5 L
| Screws, Creepage distance and clearance
" i8 [2 D9 W) r& g7 x( A/ m | 21.19* F* k7 ^2 T' Q$ n- B {% H
| 60745-1(ed.4)
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Standard(s):: \! P, i3 {8 R- `2 e1 O7 A
IEC 60745-1:2006& @; n1 q* L) U; H U7 A9 ^9 A1 A* L3 ]
Sub-clause(s):: k6 J, I- F- j* p: |$ w
21.19' q; k% o% I8 O4 ?. e
No. Year) b* D' e$ M0 e
DSH
2 N$ z3 Y8 S" |2 F% D) ~754
0 s7 F! u$ Q( r4 k( C0 O+ p2010
& [3 P. Q1 {; u$ ]( d) LCategory: TOOL Developed by: ETF 1
( r- c- h2 b# A TSubject:
: w, y" Y) m l+ D+ Q9 AScrews, Creepage
! B) ^9 X' B- @9 V7 \; C! u6 _distance and clearance
% g6 H1 @) A5 C8 l6 VKey words:
( L* {7 Z: W! F* V0 h3 ?# d- Screws0 n' W: o9 C# z" {% h' T
- force
3 C. E6 x% M$ k/ T- Creepage distance and
2 k7 u1 p2 Q3 b- q2 S( W" _clearance' U7 P8 A% i! r5 i/ D/ G2 d5 O
Approved at the 2010 CTL8 \5 |7 R1 K% F$ a) T2 Q7 B0 n
Plenary Meeting$ ^9 F8 [) t* X- ~) ]+ _
Question:
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' T# y0 f3 S2 b9 x4 A3 Y1 _. r) N“Tools shall be so designed that the protection against electric shock is not affected when
4 ^/ B* K( X- y% X9 y" G! I3 @screws intended for replacement from the outside during routine servicing are replaced by9 k! D4 V$ F: D8 S F/ ]
screws having a greater length.”+ W* m/ P2 a4 W$ W1 t& h3 {. s$ b
What screw should be used? Only the screws from equipment under test or any other
: ^' [" v# L& A* n1 N& @# @; upossible screw?2 z/ k6 ^ J+ L7 W! S
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“Compliance is checked by inserting longer screws, without appreciable force, after which! g0 _3 I9 g7 T1 ~$ _
creepage distances and clearances between live parts and accessible metal parts shall not; J# A) t: D/ v" T- E
have been reduced below the values specified in 28.1”" `- D/ l& e( G! S: Y1 J1 z
What force is to be applied?
" A1 t( T. r) q" Q& ?Decision:# L k+ g7 h( }% _& G; \
1)
$ V) [% Q. C) z9 o; IThe screw originally used on the equipment and any other longer screw that can be found* K/ c- Q2 O2 v! ^! c
on the equipment is to be used.; z A! W+ w0 _) F3 Z
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The force values in Table 9 shall be applied.
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