IEEE C37.21-2017 pdf download

IEEE C37.21-2017 pdf download.IEEE Standard for Control Switchboards.
6. Tests
6.1 General
This clause establishes physical and electrical conditions for tests. No statement in this clause is to be construed as modifying the test requirements for devices included in the switchboard assemblies. Tests are classified as design tests, production tests, and field dielectric tests, as specified in 6.2 through 6.4.
6.2 Design tests
Design tests as applicable shall be made in accordance with 6.2. 1 through 6.2.5.
6.2.1 Surge withstand capability (SWC) test
The SWC test is a standard design test of a relay system and in particular a static relay system. The intent of the SWC test is to prove that a given relay system will not misoperate or be damaged when subjected to high-voltage transients.
The components, which make up a static relay system, will vary depending on system design requirements. Therefore, the user and manufacturer shall determine what constitutes the relay system to be tested. For details of the test recommended, see IEEE Std C37.90.2.
6.2.2 Rain test for outdoor control switchboard
Referto IEEE Std C37.l00.l.
6.2.3 Flame resistance test
Sheet, molded, or cast insulating material used in a control switchboard shall not be classified as flame resistant unless they have a minimum average ignition time of 60 s and a maximum average burning time of 500 s when tested in accordance with method II ofASTM D229. As an alternate to the test required in the previous sentence, the materials shall meet the requirements in the clause on classification of insulating materials in IEEE StdC37.13.
6.2.4 Rod entry test
This test shall be made by attempting to insert a straight rod having diameter of 12.7 mm, except that, if the distance between the openings and the nearest live part is greater than 10 cm, the opening may permit the entry of a straight rod having a diameter greater than 12.7 mm, but does not permit the entry of a straight rod having a diameter greater than 19.0 mm.
The enclosure is considered to have met the requirements of this test if the appropriate rod has not entered the enclosure or is restricted by a barrier from intnis ion into the enclosure interior.
6.2.5 Coating (paint) qualification test
The coating qualification test applies to all switchboards incorporating external ferrous parts. Nonferrous switchboards with no external ferrous parts need not be tested.
The coating qualification test shall be performed to ensure the adequacy of finishes to inhibit the buildup of rust on ferrous metal materials used for switchboards.
6.2.5.1 Test specimens
Representative test panels of a 7.5 cm x 15Cm minimum size that can be accommodated by the test chamber shall he provided. Each specimen shall he uniformly processed in the standard production paint finishing system. At least four panels shall be selected for the test. The test specimens shall he of standard-gauge ferrous metal equivalent to that used for the enclosure. The specimens shall be allowed to age for a minimum of 7 d before being tested.
6.2.5.2 Test apparatus
The test apparatus shall consist of a fog chamber, salt solution reservoir, compressed air supply, provisions for heating, and means of control. The conditions in the salt spray chamber, including the positioning of the specimens, content of the salt solution, and temperature and pressure to be maintained, shall be as defined in
ASTM BI 17.
6.2.5.3 Preparation of test specimens
Two of the test panels shall be suitably scribed for testing in accordance with ASTM D 1654.
6.2.5.4 Exposure to test specimens
All test specimens shall be tested in the salt spray chamber for a period of 600 h continuously, except for short daily interruptions necessary to inspect the test specimen or replenish the solution in the reservoir.
6.2.5.5 Procedure
After completion of the exposure period, the scribed specimens shall he processed in accordance with method 2 (knife) as defined in ASTM Dl 654.
6.2.5.6 Evaluation
The scribed specimens shall then be evaluated for creepage from the scribe mark in accordance with Rating Table 1 ofASTM D 1654. The nonscribed specimens shall be evaluated for degree of blistering in accordance with ASTM D7l4.
6.2.5.7 Performance
The scrihed specimens shall he judged to have met the requirements of the test if their rating number is five orhigher as determined byASTM D1654. The nonscribed specimens shall bejudged to have met the requirements of the test if their blistering size is six or higher, and their frequency designation is F or M as determined byASTM D714.