小米 发表于 2012-9-14 13:16

DSH 280 Use of taptile screw to provide earthing continuity


http://decisions.iecee.org/icons/ecblank.gif DSH 280

Use of taptile screw to provide earthing continuity
28.3
60335-1(ed.3)


Standard: IEC 60335-1, Ed. 3.0 Sub clause: 28.3 Sheet n. 280
Page 1(2)
Subject: Use of taptile screw to
provide earthing continuity
Key words:
- taptile screw
- earthing
Decision n. 20
taken
at 36th meeting/1999
Question: A taptile screw is a screw providing self tapping during screwing.
Is this type of screw considered as a thread cutting or space thread screw regarding
requirements of sub clause 28.3 (at least two screw are necessary to provide
earthing continuity) or is considered as a machine screw (only one screw is
sufficient)?
(See drawing on page 2).
Decision: Only one taptile screw is enough to provide earthing continuity, if the screw has
the same thread than a machine screw and if the shape is round.


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