IEEE Std C37.20.7:2001 pdf free download

IEEE Std C37.20.7:2001 pdf free download.lEEE Guide for Testing Medium-Voltage Metal-Enclosed Switchgear for Internal Arcing Faults.
a) The test should be carried out on a compartment(s) not previously subjected to internal arcing.
b) The mounting arrangements of the test specimen should he as prescribed by the mann fact urer,
c) The configuration of each vertical section should be as follows:
1) The vertical section(s) should be fully equipped. Mockups of internal components may be substituted, provided that they have the same volume and are of similar material as (he original items.
2) The compartments within the vertical section should be representative of the minimum volume utilized for the maximum size component and the maximum unhraced wall surface utilized by the design. The sample should contain the maximum number of openings designed for equipment ventilation and the minimum number of openings designed for arc fault pressure relief.
3) All ventilation openings utilized for equipment cooling and designed to close during an overpressure event must be open and functional prior to starting the test.
4) If the equipment is intended for use with control devices, such as relays and meters, mounted on exposed doors or covers, a representative sample of these devices should be present on the test specimen, When this is not practical. the compartment directly behind the mounting point should be evaluated to verify that any abnormal pressure developed during the test will not cause the mounted devices to he displaced or allow exposure to the arc. Indicators should be placed inside this compartment to verify that the etl’ects of the fault do not enter into the compartment.
5) Any openings created in the equipment as a result of manufacturing, assembly, or modification. which have an intentional covering. plug. or similar device. may have that device installed. Openings that do not have intentional coverings cannot be blocked in any way for this test.
d) The test specimen should be grounded at the normal ground point(s) or to the test supply neutral through an adequate conductor.
e) The arc should be initiated in a way that is representative of fliults that could occur under service conditions. Sec 7.1 for typical locations for fault initiation.