DSH 261 Requiremwents for parts providing earth continuity
http://decisions.iecee.org/icons/ecblank.gif DSH 261
Requiremwents for parts providing earth continuity
27, 28.3, 28.4
60335-1(ed.3)
Standard: IEC60335-1, Ed. 3 Sub clauses: 27, 28.3, 28.4
Sheet n. 261
Subject: Requirements for parts providing earth continuity
Key words:
- resistance to corrosion
- space threaded screw
Decision n. 17 taken at 35th meeting/1998
Questions:
1. Clause 27.4 requires that parts providing earth continuity shall have adequate resistance
to corrosion. In particular, steel parts are required to have at least 5μm electroplating
On what basis are laboratories stating compliance for this requirement?
2. In the instance where a space threaded screw is used to provide earthing provision for a
motor frame (for instance), is the use of a space threaded screw without the use of a spring
washer a satisfactory earthing method for unpainted surfaces, considering the requirements
of clauses 28.3 and 28.4, with the example of figure below ?
Decisions:
1 – The adequate thickness of electroplated coating for steel part providing earth continuity
is checked as indicated in note 4, using ISO2178 or ISO1463. The manufacturer declaration
of compliance is also accepted.
2- The construction presented is not acceptable. The use of space threaded screws is only
acceptable if two space-threaded screw are used (§28.3). In this case, no spring washer is
required (§28.4). The use of only one space-threaded screw with spring washer is not in
accordance with the standard.
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