ASTM B942-21

Standard Guide for Specification and Quality Assurance for the Electrical Contact Performance of Crimped Wire Terminations

SIGNIFICANCE AND USE
4.1 The purpose of this guide is to provide end-product manufacturers and other users with technical information and methods recommended towards the achievement of successful application of crimped wire terminals.  
4.2 For any given use, there is generally a choice of terminal types available, employing different mechanical design, materials, and installation tooling. Although terminals available to choose from may be similarly rated, typically according to wire sizes and combinations, their electrical contact performance in the end product may vary substantially. For many applications, the end-product reliability and user safety is substantially influenced by the choice of terminal and the quality of the completed termination. This guidance document contains specialized information on selection, assembly, and quality control of crimped wire terminals, covering aspects considered to be necessary to achieve reliable long-term operation in the intended application. This information is not generally found in commercial literature or textbooks. The methods discussed utilize connection resistance as the primary measure of termination quality, and change of connection resistance with time as the measure of termination deterioration. The methods are based on a foundation of modern electrical contact theory and practice.
SCOPE
1.1 This guide contains practices for specifying and evaluating the electrical contact performance of crimped-type terminations with solid or stranded conductors.  
1.2 This guide provides information relevant to the electrical contact performance of a crimped wire termination. It does not cover other aspects of selection and use of crimped terminals.  
1.3 The methods discussed in this guide apply only to the wire termination, which is the electrical contact interface between the conductor(s) and the terminal. Other aspects important to terminal evaluation, such as the properties and performance of electrical insulation, the effectiveness of strain relief features, and the quality of contact between the terminal and other electrical circuit elements, are not included.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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 become familiar with all hazards including those identified in the appropriate Safety Data Sheet (SDS) for this product/material as provided by the manufacturer, to establish appropriate safety, health, and environmental practices, and determine the applicability of regulatory limitations prior to use.  
1.6 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.

General Information

• Status: Published
• Publication Date: 31-Mar-2021
• ICS: 29.120.20 - Connecting devices
• Technical Committee: B02 - Nonferrous Metals and Alloys
• Drafting Committee: B02.05 - Precious Metals and Electrical Contact Materials and Test Methods

Standards Content (Sample)

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.
Designation: B942 − 21
Standard Guide for
Specification and Quality Assurance for the Electrical
1
Contact Performance of Crimped Wire Terminations
This standard is issued under the fixed designation B942; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This guide contains practices for specifying and evalu-
B539 Test Methods for Measuring Resistance of Electrical
ating the electrical contact performance of crimped-type ter-
Connections (Static Contacts)
minations with solid or stranded conductors.
B542 Terminology Relating to Electrical Contacts and Their
1.2 This guide provides information relevant to the electri-
Use
cal contact performance of a crimped wire termination. It does
B827 Practice for Conducting Mixed Flowing Gas (MFG)
not cover other aspects of selection and use of crimped
Environmental Tests
terminals.
B845 Guide for Mixed Flowing Gas (MFG) Tests for Elec-
trical Contacts
1.3 The methods discussed in this guide apply only to the
B913 Test Method for Evaluation of Crimped Electrical
wire termination, which is the electrical contact interface
Connections to 16-Gauge and Smaller Diameter Stranded
between the conductor(s) and the terminal. Other aspects
and Solid Conductors
important to terminal evaluation, such as the properties and
E122 Practice for Calculating Sample Size to Estimate, With
performance of electrical insulation, the effectiveness of strain
Specified Precision, the Average for a Characteristic of a
relief features, and the quality of contact between the terminal
Lot or Process
and other electrical circuit elements, are not included.
3
2.2 Other References:
1.4 The values stated in SI units are to be regarded as
UL 486-A Wire connectors and Soldering Lugs for Use With
standard. No other units of measurement are included in this
Copper Conductors
standard.
UL-310 Electrical Quick-Connect Terminals
1.5 This standard does not purport to address all of the
3. Terminology
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to become familiar 3.1 Many terms related to electrical contacts used in this
with all hazards including those identified in the appropriate guide are defined in Terminology B542.
Safety Data Sheet (SDS) for this product/material as provided
3.2 Definitions of Terms Specific to This Standard:
by the manufacturer, to establish appropriate safety, health,
3.2.1 connection resistance, n—the electrical resistance at-
and environmental practices, and determine the applicability
tributable to a wire termination over and above that of an
of regulatory limitations prior to use.
identical solid metallic structure without pressure contact
1.6 This international standard was developed in accor-
interfaces. For crimped terminations that are the subject of this
dance with internationally recognized principles on standard-
guide, the connection resistance results from the resistance of
ization established in the Decision on Principles for the
a multitude of contact regions having both film and constriction
Development of International Standards, Guides and Recom- resistance, plus, where stranded wire is involved, an additional
mendations issued by the World Trade Organization Technical amount due to unequal current distribution among the wire
Barriers to Trade (TBT) Committee. strands at the termination.
1 2
This guide is under the jurisdiction of ASTM Committee B02 on Nonferrous For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Metals and Alloys and is the direct responsibility of Subcommittee B02.05 on contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Precious Metals and Electrical Contact Materials and Test Methods. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved April 1, 2021. Published April 2021. Originally the ASTM website.
3
approved in 2005. Last previous edition approved in 2015 as B942 – 10 (2015). Available from Underwriters Laboratories (UL), UL Headquarters, 333 Pfing-
DOI: 10.1520/B0942-21. sten Road, Northbrook, IL, 60062, http://www.ul.com.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
B942 − 21
3.2.2 crimp, v—to establish an electrical and mechanical maintain that cont
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: B942 − 10 (Reapproved 2015) B942 − 21
Standard Guide for
Specification and Quality Assurance for the Electrical
1
Contact Performance of Crimped Wire Terminations
This standard is issued under the fixed designation B942; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This guide contains practices for specifying and evaluating the electrical contact performance of crimped-type terminations
with solid or stranded conductors.
1.2 This guide provides information relevant to the electrical contact performance of a crimped wire termination. It does not cover
other aspects of selection and use of crimped terminals.
1.3 The methods discussed in this guide apply only to the wire termination, which is the electrical contact interface between the
conductor(s) and the terminal. Other aspects important to terminal evaluation, such as the properties and performance of electrical
insulation, the effectiveness of strain relief features, and the quality of contact between the terminal and other electrical circuit
elements, are not included.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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 become familiar with all hazards including those identified in the appropriate Safety Data Sheet
(SDS) for this product/material as provided by the manufacturer, to establish appropriate safety safety, health, and healthenvi-
ronmental practices, and determine the applicability of regulatory limitations prior to use.
1.6 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.
2. Referenced Documents
2
2.1 ASTM Standards:
B539 Test Methods for Measuring Resistance of Electrical Connections (Static Contacts)
B542 Terminology Relating to Electrical Contacts and Their Use
B827 Practice for Conducting Mixed Flowing Gas (MFG) Environmental Tests
B845 Guide for Mixed Flowing Gas (MFG) Tests for Electrical Contacts
3
B868 Practice for Contact Performance Classification of Electrical Connection Systems (Withdrawn 2017)
1
This guide is under the jurisdiction of ASTM Committee B02 on Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee B02.11 on Electrical
Contact Test Methods.
Current edition approved Oct. 1, 2015April 1, 2021. Published October 2015April 2021. Originally approved in 2005. Last previous edition approved in 20102015 as
ɛ1
B972B942 – 10 (2015). 10 . DOI: 10.1520/B0942-10R15.10.1520/B0942-21.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
B942 − 21
B913 Test Method for Evaluation of Crimped Electrical Connections to 16-Gauge and Smaller Diameter Stranded and Solid
Conductors
E122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or
Process
3
2.2 Other References:
UL 486-A Wire connectors and Soldering Lugs for Use With Copper Conductors
UL-310 Electrical Quick-Connect Terminals
3. Terminology
3.1 Many terms related to electrical contacts used in this guide are defined in Terminology B542.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 connection resistance, n—the electrical resistance attributable to a wire termination over and above that of an identical solid
metallic structure without pressure contact interfaces. For crimped terminations that are the subject of this guide, the connection
resistance results from the resistance of a multitude of contact regions having both film and constriction resistance, plus, where
stranded wire is involved, an additional amount due
...