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EN60950-1:2006# R0 J6 I( Q1 s4 I
4.2.7 Stress relief test
3 A& S0 Z7 i7 U8 {- eENCLOSURES of moulded or formed thermoplastic materials shall be so constructed that any! i7 }! S( ~7 x7 ?0 d
shrinkage or distortion of the material due to release of internal stresses caused by the
2 Z) Y3 R! \, E I4 Xmoulding or forming operation does not result in the exposure of hazardous parts or in the$ {' ~ X# R; J7 _
reduction of CLEARANCES or CREEPAGE DISTANCES below the values specified in 2.10 (or D0 h7 B- Y7 C( z$ D
Annex G).
/ d5 b/ w7 X J+ v5 j. l9 OCompliance is checked by the test procedure described below or by the inspection of the
6 t, \# E4 R* |# H6 }. X/ vconstruction and the available data where appropriate.) G1 O4 T9 x5 d- R7 s
One sample consisting of the complete equipment, or of the complete ENCLOSURE together
+ x/ ?/ b6 g$ awith any supporting framework, is placed in a circulating air oven (according to
9 |& g3 q. ?! f4 tIEC 60216-4-1) at a temperature 10 K higher than the maximum temperature observed on the# N& n% u' S% ?4 H) f; p
ENCLOSURE during the test of 4.5.2, but not less than 70 ° C, for a period of 7 h, then permitted
1 j, C8 q- S# n/ N8 [. O bto cool to room temperature.7 M7 v9 Y; e j4 v
With the concurrence of the manufacturer, it is permitted to increase the above time duration.
, V. B6 V- y0 T% b; x z9 @5 v0 YFor large equipment where it is impractical to condition a complete ENCLOSURE, it is permitted
9 F4 P/ E# h! d T/ X5 k3 Uto use a portion of the ENCLOSURE representative of the complete assembly with regard to- t* w1 L9 v/ }$ t* u4 O% F7 c; x
thickness and shape, including any mechanical support members.8 ^9 p+ O; G; q9 f
NOTE Relative humidity need not be maintained at a specific value during this test.) S% z5 P/ z& y% K+ n! m* x
If the above test is conducted, the compliance criteria of 4.2.1 apply. |
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