DSH 717 Creepage and clearance determination, groove, recess, corner, bridging o

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IEC60335试验指甲

DSH 717 " w  f7 T5 e9 P

Creepage and clearance determination, groove, recess, corner, bridging of distance X

4.2, 6.2

60664-1(ed.1.2) & 60065-1(ed.2) & All equipment standards based on these

# ]! _. ]5 Q6 t( l3 ]1 G- N" AStandard(s): No. Year
; |+ _9 S% [( _& `2 b, U4 nIEC 60664-1/2002 ed1.2
IEC 60664-1/2007 ed2.0
All equipment standards
7 p$ ]4 ]. {& o' {* a& d* Y. Sbased on these
1 U, j, Z$ f: m# Y- u5 NDSH
3 J) [6 }4 O/ v. l9 d- W( w; O0717
# u: ]9 l- b) J, b6 h) x" y9 s6 t) q2008
Categories:
+ p4 v: l6 Z, C4 ]Various, General
Subclause(s):
* y/ M: k) ^) K- x6 E* w0 ^( D- V4.2
6.2
0 n  e8 i1 n9 o/ u! IDeveloped by:
WG2 - WG4
Subject:
Creepage and clearance
9 E) R: {3 d' @) ]* c, Z7 vdetermination, groove,
6 C' Y. T5 \8 K- wrecess, corner, bridging
of distance X
Key words:
- Creepage
- Clearance
% y  ?. ?8 I( E) K2 K- a% Y- Groove
- Recess
- Corner
- Bridging of distance
X
& \* }$ v& f$ L% XDecision approved at the
2009 CTL Plenary
# f8 M1 E: x# Z. L6 C( \" hMeeting
% y6 _" a# V. w) @' \Questions:
1) How shall the examples given in IEC 60664 be interpreted for intermediate situations?
2) How shall the example given below be judged correctly, based on the examples given in
' g9 \& Q! V/ F/ G1 d2 fIEC 60664-1 and based on the assumption that X = 1 mm?
0,8mm
2 mm
PCB
- \. v# b" r0 I% OPCB-Track (ending on the
edge of the cut-out
7 ]  x0 B( [3 `# G3) When shall the sentence:
“If the associated clearance is less than 3 mm, the minimum dimension X may be reduced to
one third of this clearance.” be applied?
Does this sentence refer to the actual clearance measured or to the minimum clearance
required?
) K8 z, e- O! P4 k& B0 n% I; hDecisions:
+ k9 l4 i* I/ |Ad 1)
3 Y( p8 v, w' P8 j! {( xAn intermediate situation not covered directly by the Standard shall be determined by
: K3 G' w2 }) n8 [; h1 Zconsidering it as an extension of the most appropriate example from the Standard. An example
of the methodology is given in the Explanatory Notes to Question 2."
1 m+ B, {; E  B2 PAd 2)
; E5 M  ]0 \& |The example shall be judged without any bridging of the corner in the cut-out

creepage = 2,8 mm, no shortcut applicable.
- a. ~2 Q% G9 E6 lAd 3)
1 |# m) f% T4 v4 J! |The sentence shall always be applied whenever the required clearance is less than
3 mm and the allowed reduction of the minimum dimension X shall be referred to 1/3 of the
required minimum clearance.
; V$ ^  A" U: |( W7 R$ G  l" D