ASTM D495-22
Standard Test Method for High-Voltage, Low-Current, Dry Arc Resistance of Solid Electrical Insulation

Standard No.

ASTM D495-22

Release Date

2022

Published By

American Society for Testing and Materials (ASTM)

Latest

ASTM D495-22

Scope

1.1 This test method covers, in a preliminary fashion, the differentiation of similar materials’ resistance to the action of a high-voltage, low-current arc close to the surface of insulation, when a conducting path is formed causing the material to become conducting due to the localized thermal and chemical decomposition and erosion. 1.2 The usefulness of this test method is very severely limited by many restrictions and qualifications, some of which are described in the following paragraphs and in Section 5. Generally, this test method shall not be used in material specifications. Whenever possible, alternative test methods shall be used, and their development is encouraged. 1.3 This test method will not, in general, permit conclusions to be drawn concerning the relative arc resistance rankings of materials that are potentially subjected to other types of arcs: for example, high voltage at high currents, and low voltage at low or high currents (promoted by surges or by conducting contaminants). 1.4 The test method is intended, because of its convenience and the short time required for testing, for preliminary screening of material, for detecting the effects of changes in formulation, and for quality control testing after correlation has been established with other types of simulated service arc tests and field experience. Because this test method is usually conducted under clean and dry laboratory conditions rarely encountered in practice, it is possible that the prediction of a material’s relative performance in typical applications and in varying “clean to dirty” environments will be substantially altered (Note 1). Caution is urged against drawing strong conclusions without corroborating support of simulated service tests and field testing. Rather, this test method is useful for preliminary evaluation of changes in structure and composition without the complicating influence of environmental conditions, especially dirt and moisture. NOTE 1—By changing some of the circuit conditions described herein it has been found possible to rearrange markedly the order of arc resistance of a group of organic insulating materials consisting of vulcanized fiber and of molded phenolic and amino plastics, some containing organic, and some inorganic, filler. 1.5 While this test method uses dry, uncontaminated specimen surfaces, Test Method D2132, Test Methods D2303, and Test Method D3638 employ wet, contaminated specimen surfaces. Their use is recommended for engineering purposes and to assist in establishing some degree of significance to this test method for quality control purposes.2 1.6 This test method is not applicable to materials that do not produce conductive paths under the action of an electric arc, or that melt or form fluid residues that float conductive residues out of the active test area thereby preventing formation of a conductive path. 1.7 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see 6.1.14, 6.1.19, Section 7, and 10.1.1. NOTE 2—Due to the deficiencies covered in Section 1, Committee D09 has proposed that without significant proposed improvements this standard be withdrawn in 2027 during its next 5 year review. This notice is provided so that referencing standards can transition. 1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the 1 This test method is under the jurisdiction of ASTM Committee D09 on Electrical and Electronic Insulating Materials and is the direct responsibility of Subcommittee D09.12 on Electrical Tests. Current edition approved Jan. 15, 2022. Published January 2022. Originally approved in 1938. Last previous edition approved in 2014 as D495 – 14. DOI: 10.1520/D0495-22. 2 Also helpful is Test Method D2302 for Wet Tracking Resistance of Electrical Insulating Materials with Controlled Water-to-Metal Discharges. This test method was withdrawn and last appeared in the 1982 Annual Book of ASTM Standards, Part 39. *A Summary of Changes section appears at the end of this standard Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. 1 Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

ASTM D495-22 Referenced Document

• ASTM D1711 Standard Terminology Relating to Electrical Insulation
• ASTM D2132 Standard Test Method for Dust-and-Fog Tracking and Erosion Resistance of Electrical Insulating Materials
• ASTM D2303 Standard Test Methods for Liquid-Contaminant, Inclined-Plane Tracking and Erosion of Insulating Materials
• ASTM D3638 Standard Test Method for Comparative Tracking Index of Electrical Insulating Materials
• ASTM D6054 Standard Practice for Conditioning Electrical Insulating Materials for Testing

ASTM D495-22 history

• 2022 ASTM D495-22 Standard Test Method for High-Voltage, Low-Current, Dry Arc Resistance of Solid Electrical Insulation
• 2014 ASTM D495-14 Standard Test Method for High-Voltage, Low-Current, Dry Arc Resistance of Solid Electrical Insulation
• 1999 ASTM D495-99(2004) Standard Test Method for High-Voltage, Low-Current, Dry Arc Resistance of Solid Electrical Insulation
• 1999 ASTM D495-99(2000) Standard Test Method for High-Voltage, Low-Current, Dry Arc Resistance of Solid Electrical Insulation
• 1999 ASTM D495-99 Standard Test Method for High-Voltage, Low-Current, Dry Arc Resistance of Solid Electrical Insulation