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EN60950-1:20065 P7 ]. N1 Z/ {" Z1 N! E
4.2.7 Stress relief test
1 ~; x# L! d7 B l3 a* {& oENCLOSURES of moulded or formed thermoplastic materials shall be so constructed that any) j9 j+ ^; |6 b |) C6 ?
shrinkage or distortion of the material due to release of internal stresses caused by the8 `5 t3 O; j5 J" K; V4 H5 I1 K
moulding or forming operation does not result in the exposure of hazardous parts or in the
5 W5 K9 M1 W; J" r a$ {" A% T; Dreduction of CLEARANCES or CREEPAGE DISTANCES below the values specified in 2.10 (or
+ U) u) c& O8 F7 U& m- W' f4 fAnnex G).
* V4 G9 `3 V% t, eCompliance is checked by the test procedure described below or by the inspection of the
' V: R7 G4 S ^0 d2 X4 f9 `construction and the available data where appropriate.5 \) J0 \9 E4 d W5 `8 g
One sample consisting of the complete equipment, or of the complete ENCLOSURE together0 {. n a: j8 |, N e: H
with any supporting framework, is placed in a circulating air oven (according to4 |8 |! N: }* Q4 e
IEC 60216-4-1) at a temperature 10 K higher than the maximum temperature observed on the
' R8 q% P$ v, I! DENCLOSURE during the test of 4.5.2, but not less than 70 ° C, for a period of 7 h, then permitted5 j/ ]! I8 W# |+ R0 ?
to cool to room temperature.0 _# n0 x0 A1 F
With the concurrence of the manufacturer, it is permitted to increase the above time duration.
3 ~$ a6 J, [' g" qFor large equipment where it is impractical to condition a complete ENCLOSURE, it is permitted
5 B- s" i- Q! S% ~+ w8 xto use a portion of the ENCLOSURE representative of the complete assembly with regard to0 i3 S, y" m. F a
thickness and shape, including any mechanical support members., e c) b: S0 K1 Z
NOTE Relative humidity need not be maintained at a specific value during this test.4 a. }5 y+ y; Y' b1 Q6 f, X+ n
If the above test is conducted, the compliance criteria of 4.2.1 apply. |
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