Design and Critical Process Requirements

IPC-D-620-2013

This is the IPC-D-620_Jan2013 variant selected by the 7-31K committee at APEX 2013 (02/20/2013) to serve as the requirement document.

It retains the Performance Classification (1-2-3) but modifies the original draft’s QA requirement format (N/A/P/D) to an Applicable / Not Applicable format (A/N), and brings in a new Appendix A (CLASS 3/A Military / Space).

IPC-D-620

DESIGN AND CRITICAL PROCESS REQUIREMENTS

FOR

CABLE AND WIRING HARNESSES

7-31h/7-31k Wire Harness Design Task Group

Working Draft: IPC-D-620_2013

Includes eEdits from IPC Fall 2013 meeting (10/17/2013)

Includes working edits from IPC APEX 2014 meeting (03/26/2014)

03/1811/12/2013

09/02/2014 – SMTAI14

FOREWORD

This standard is intended to provide information on the design requirements for cable and wiring harness design, to the extent that they can be applied to the broad spectrum of cable and wiring harness design.

It is therefore crucial that decisions concerning the choice of product classification, wiring technology, connectorization requirements, and performance and reliability requirements be made as early as possible.

IPC-D-620 is supplemented by Appendices A-E and a handbook (IPC-HDBK-620), which provide the engineering rationale and technical guidance on cable and wiring harness design. The USER needs, as a minimum, the Design Requirements document (IPC-D-620), and the engineering description of the final product.

As wiring and connector technology changes, specific requirements will be updated or new requirements added to the document set.

The IPC invites input on the effectiveness of the documentation and encourages USER response through completion of ‘‘Suggestions for Improvement’’ forms located at the end of each document

TABLE OF CONTENTS

1. purpose 7

1.1 scope 7

1.2 performance / product classification 7

1.3 definition of requirements 7

1.3.1 requirement format (a/n) 8

1.3.2 line drawings and illustrations 8

1.4 measurement units and applications 8

1.5 definition of terms 8

1.6 engineering documentation 9

1.7 order of precedence 9

1.7.1 conflict 9

1.7.2 clause references 9

1.8 appendices 9

1.9 approval of departures from standards and requirements 9

2. applicable documents 11

2.1 aerospace 11

2.2 commercial 11

2.3 federal 12

2.4 military handbooks 12

2.5 military specifications 12

2.6 reference 13

3. design philosophy 15

3.1 general design requirements 15

3.1.1 end-product requirements 16

3.1.1.1 performance and reliability 16

3.1.1.2 interchangeability 16

3.1.1.3 design for maintenance (dom) 16

3.1.1.4 cable / harness management (routing) 16

3.1.1.5 ergonomic design 17

3.1.1.6 service life 17

3.1.2 environment 17

3.1.3 storage and transportability 17

3.1.4 workmanship 18

4. selection of parts, materials and processes 19

4.1 commonality 19

4.2 flammability 19

4.3 outgassing 19

4.4 restricted materials / processes 19

4.4.1 glass / glass-like materials 19

4.4.2 crimping of solder-tinned and solid conductors 19

4.4.3 splices 20

4.4.4 cuprous oxide corrosion (red plague) 20

4.4.5 fluorine attack (white plague) 20

4.4.6 lead-free tin (<3% pB) technology – control level 2c 20

4.5 time-critical or limited-life 21

4.6 wire & cable 21

4.6.1 conductor sizing 21

4.6.2 conductor material and coating 22

4.6.3 multi-conductor cables 22

4.6.4 coaxial cables 23

4.6.5 optical fiber, optical fiber cable, and optical fiber assemblies 23

4.7 connectors 24

4.7.1 mating provisions 25

4.7.2 moisture protection 25

4.7.3 pin assignment 25

4.7.4 protection of connectors 26

4.7.5 protection of severed electrical circuits 26

5 electrical requirements 27

5.1 derating 27

5.2 corona suppression 27

5.3 circuit categories 28

5.3.1 category i (power and control) 28

5.3.2 category ii (high level signals) 28

5.3.3 category iii (low-level signals) 28

5.3.4 category iv (electro explosive device circuits) 28

5.3.5 category v (high-frequency signals) 28

5.4 shielding (by circuit category) 28

5.4.1 category i circuits 28

5.4.2 category ii circuits 28

5.4.3 category iii circuits 28

5.4.4 category iv circuits 29

5.4.5 category v circuits 29

5.4.6 additional shielding 29

5.5 bonding 29

5.6 shield design and grounding 30

5.6.1 electromagnetic pulse (emp) environment 30

5.6.2 category iv circuits 30

5.6.3 category i, ii, iii, and v circuits (no emp) 31

5.6.4 ungrounded / floating shield terminations (no emp) 31

5.6.5 magnetic shields 31

5.7 circuit isolation 31

5.7.1 group-grounding of individual shield terminations 32

5.7.2 separation of redundant systems 32

6 assembly / fabrication requirements 38

6.1 wire terminations 38

6.1.1 splices (use of) 38

6.1.2 dead-ending 38

6.1.3 insulation compatibility with sealing and servicing 39

6.2 form layout fixture 39

6.3 forming wires into cables and harnesses 40

6.4 wire lay 40

6.5 bend radius 40

6.6 protection and support 40

6.7 etching fluoropolymer-insulated electrical wire 41

6.8 identification and marking 41

6.8.1 cable and harness assemblies 42

6.8.2 optical cable 42

6.8.3 coaxial cable 42

6.8.4 connectors 42

6.8.5 clamp locating marks 42

7 quality assurance requirements 44

7.1 responsibility for inspections and tests 44

7.2 classification of inspections and tests 44

7.3 workmanship, acceptance, and testing 44

7.4 qualification 44

8 documentation 46

8.1 data 46

8.2 connector orientation (clocking) 46

8.3 connector pin-out 47

8.4 dimensioning and tolerance 47

9 tailoring 48

10 definitions and acronyms 50

10.1 definitions 50

10.2 acronyms and abbreviations 53

appendix a - class 3/a Military / Space 56

appendix b - red plague control plan 62

appendix c - restricted materials / processes 74

appendix d - foreign object debris (fod) control 80

appendix e - electrical wire and cable acceptance tests 82

appendix f – bend radius 84

appendix g – lead-free control plan (lfcp) 86

1. PURPOSE 7

1.1 SCOPE 7

1.2 PERFORMANCE / PRODUCT CLASSIFICATION 7

1.3 DEFINITION OF REQUIREMENTS 8

1.3.1 REQUIREMENT FORMAT (A/N) 8

1.3.2 LINE DRAWINGS AND ILLUSTRATIONS 8

1.4 MEASUREMENT UNITS AND APPLICATIONS 8

1.5 DEFINITION OF TERMS 9

1.6 ENGINEERING DOCUMENTATION 9

1.7 ORDER OF PRECEDENCE 9

1.7.1 CONFLICT 9

1.7.2 CLAUSE REFERENCES 9

1.8 APPENDICES 9

1.9 APPROVAL OF DEPARTURES FROM STANDARDS AND REQUIREMENTS 9

2. APPLICABLE DOCUMENTS 11

2.1 AEROSPACE 11

2.2 COMMERCIAL 11

2.3 FEDERAL 12

2.4 MILITARY HANDBOOKS 12

2.5 MILITARY SPECIFICATIONS 12

2.6 REFERENCE 13

3. DESIGN PHILOSOPHY 15

3.1 GENERAL DESIGN REQUIREMENTS 15

3.1.1 END-PRODUCT REQUIREMENTS 16

3.1.1.1 RELIABILITY 16

3.1.1.2 INTERCHANGEABILITY 16

3.1.1.3 DESIGN FOR MAINTENANCE (DOM) 16

3.1.1.4 CABLE / HARNESS MANAGEMENT (ROUTING) 17

3.1.1.5 ERGONOMIC DESIGN 18

3.1.1.6 SERVICE LIFE 18

3.1.2 ENVIRONMENT 18

3.1.3 STORAGE AND TRANSPORTABILITY 18

3.1.4 WORKMANSHIP 18

4. SELECTION OF PARTS, MATERIALS AND PROCESSES 19

4.1 COMMONALITY 19

4.2 FLAMMABILITY 19

4.3 OUTGASSING 19

4.4 CUPROUS OXIDE CORROSION (RED PLAGUE) 19

4.5 FLUORINE ATTACK (WHITE PLAGUE) 20

4.6 TIME-CRITICAL OR LIMITED-LIFE 20

4.7 WIRE & CABLE 20

4.7.1 CONDUCTOR SIZING 20

4.7.2 CONDUCTOR MATERIAL AND COATING 21

4.7.3 MULTI-CONDUCTOR CABLES 22

4.8 CONNECTORS 22

4.8.1 MATING PROVISIONS 23

4.8.2 MOISTURE PROTECTION 23

4.8.3 PIN ASSIGNMENT 23

4.8.4 PROTECTIVE COVERS OR CAPS 23

4.8.5 PROTECTION OF SEVERED ELECTRICAL CIRCUITS 23

4.9 RESTRICTED MATERIALS / PROCESSES 24

4.9.1 CRIMPING OF SOLDER-TINNED AND SOLID CONDUCTORS 24

4.9.2 SPLICES 24

5. ELECTRICAL REQUIREMENTS 25

5.1 DERATING 25

5.2 CORONA SUPPRESSION 25

5.3 CIRCUIT CATEGORIES 26

5.3.1 CATEGORY I (POWER AND CONTROL) 26

5.3.2 CATEGORY II (HIGH LEVEL SIGNALS) 26

5.3.3 CATEGORY III (LOW-LEVEL SIGNALS) 26

5.3.4 CATEGORY IV (ELECTRO EXPLOSIVE DEVICE CIRCUITS) 26

5.3.5 CATEGORY V (HIGH-FREQUENCY SIGNALS) 26

5.4 SHIELDING (BY CIRCUIT CATEGORY) 26

5.4.1 CATEGORY I CIRCUITS 26

5.4.2 CATEGORY II CIRCUITS 26

5.4.3 CATEGORY III CIRCUITS 26

5.4.4 CATEGORY IV CIRCUITS 27

5.4.5 CATEGORY V CIRCUITS 27

5.4.6 ADDITIONAL SHIELDING 27

5.5 BONDING 27

5.6 SHIELD DESIGN AND GROUNDING 28

5.6.1 ELECTROMAGNETIC PULSE (EMP) ENVIRONMENT 28

5.6.2 CATEGORY IV CIRCUITS 28

5.6.3 CATEGORY I, II, III, AND V CIRCUITS (NO EMP) 29

5.6.4 UNGROUNDED / FLOATING SHIELD TERMINATIONS (NO EMP) 29

5.6.5 MAGNETIC SHIELDS 29

5.7 CIRCUIT ISOLATION 29

5.7.1 GROUP-GROUNDING OF INDIVIDUAL SHIELD TERMINATIONS 30

5.7.2 SEPARATION OF REDUNDANT SYSTEMS 30

6. ASSEMBLY / FABRICATION REQUIREMENTS 36

6.1 WIRE TERMINATIONS 36

6.1.1 SPLICES 36

6.1.2 DEAD-ENDING 36

6.1.3 INSULATION COMPATIBILITY WITH SEALING AND SERVICING 37

6.2 FORM LAYOUT FIXTURE 37

6.3 FORMING WIRES INTO CABLES AND HARNESSES 38

6.4 WIRE LAY 38

6.5 BEND RADIUS 39

6.6 PROTECTION AND SUPPORT 39

6.7 ETCHING FLUOROPOLYMER-INSULATED ELECTRICAL WIRE <07/12/13, rwc> 39

6.8 IDENTIFICATION AND MARKING 40

6.8.1 IDENTIFICATION OF INDIVIDUAL CONDUCTORS 40

6.8.2 IDENTIFICATION OF HARNESSES 40

6.8.3 IDENTIFICATION OF CONNECTORS 41

6.8.4 TEMPORARY IDENTIFICATION 41

6.8.5 CLAMP LOCATING MARKS 41

7. QUALITY ASSURANCE REQUIREMENTS 43

7.1 RESPONSIBILITY FOR INSPECTIONS AND TESTS 43

7.2 CLASSIFICATION OF INSPECTIONS AND TESTS 43

7.3 PARTS, MATERIALS, AND PROCESS CONTROLS 43

7.4 WORKMANSHIP, ACCEPTANCE, AND TESTING 43

7.5 ACCEPTANCE CRITERIA 44

7.6 QUALIFICATION 44

8. DOCUMENTATION 45

8.1 DATA 45

8.2 CONNECTOR ORIENTATION (CLOCKING) 45

8.3 CONNECTOR PIN-OUT 46

8.4 DIMENSIONING AND TOLERANCE 46

9. TAILORING 47

10. DEFINITIONS AND ACRONYMS 49

10.1 DEFINITIONS 49

10.2 ACRONYMS AND ABBREVIATIONS 52

APPENDIX A - CLASS 3/A Military / Space 54

APPENDIX B - RED PLAGUE CONTROL PLAN 59

APPENDIX C - RESTRICTED MATERIALS 67

APPENDIX D - FOREIGN OBJECT DEBRIS (FOD) CONTROL 73

APPENDIX E - ELECTRICAL WIRE AND CABLE ACCEPTANCE TESTS 75

1. PURPOSE

“Design Requirements for Cable and Wiring Harnesses” is the design requirements companion to IPC/WHMA-A-620A, “Requirements and Acceptance for Cable and Wire Harness Assemblies”, and IPC/WHMA-A-620(ASpace), “Space Applications Electronic Hardware Addendum to IPC/WHMA-A-620A”. With the present transition from prescriptive ‘‘how to’’ specifications to performance-based standards, much of the design requirements were removed from IPC/WHMA-A-620A and IPC/WHMA-A-620AS.

The intent of this document is to set forth the general design requirements for electrical wiring harnesses and cable assemblies. The target USER of this document is a design engineer, manufacturing engineer, quality engineer, or other individual responsible for the tailoring of specific requirements of this document to the applicable performance class.

For purposes of this document, the Supplier is considered the Design Authority.

1.1 SCOPE

This document is intended to provides design and critical process requirements and technical insight that hashave been removed from the acceptance standards for cable and wire harness assemblies. Reference materials listed in this text are among those considered as required reading. The USER is encouraged to obtain all relevant referenced materials as this document cannot (nor can any single document) cover every material, process, environment, performance, or safety aspect that affect a given design.

1.2 PERFORMANCE / PRODUCT CLASSIFICATION

This document recognizes that electrical wiring harnesses and cable assemblies are subject to performance / product classifications by intended end-item use. Three general end-product classes have been established to reflect differences in producibility, complexity, functional performance requirements, and verification (inspection/test) frequency. It SHOULD be recognized that there may be requirement overlaps between classes.

The USER is responsible for defining the product class. The contract shall [A1A2A3] specify the performance class required and indicate any exceptions to specific parameters, where appropriate.

(6) The USER is responsible for defining the product class. The contract shall [A1A2A3] specify the performance class required, whether compliance to any of the A through E Appendices is required, and indicate any exceptions to specific parameters where appropriate.” <6 – Accept / 8 - withdrawn: IPC Fall – 10/17/2013><Oct13>

CLASS 1 - General Electronic Products

Includes consumer products, as well as general military hardware suitable for applications where cosmetic imperfections are not important and the major requirement is function of the completed assembly.

CLASS 2 - Dedicated Service Electronic Products

Includes products where continued performance and extended life is required, and for which uninterrupted service is desired but not critical. Typically, the end-use environment would not cause failures.

CLASS 3 - High Performance Electronic Products

Includes products where continued high performance or performance-on-demand is critical, equipment downtime cannot be tolerated, end-use environment may be uncommonly harsh, and the equipment must function when required, such as life support or other critical systems.

CLASS 3/A - Military / Space

Though not officially recognized as a separate performance classification, a specialized classification for spaceflight is levied by IPC/WHMA-A-620(SPACE), “Space Applications Electronic Hardware Addendum to IPC/WHMA-A-620”. Commonly referred to as Class 3/A, this classification includes products where continued high performance or performance-on-demand is critical, equipment downtime cannot be tolerated, end-use environment may be uncommonly harsh, and the equipment must survive the vibration and thermal cyclic environments experienced in military and spaceflight applications.

Space and Military Avionics classification deviations to IPC-D-620 are defined and listed in Appendix A., Table 1. <7 – Accept / mod.: IPC Fall – 10/17/2013>oct 13)

1.3 DEFINITION OF REQUIREMENTS

The imperative form of action verbs are used throughout this document to identify design requirements that may require compliance, depending upon the Performance Classification of the hardware. To assist the USER, these action verbs are in bold text.

a. SHALL / SHALL NOT. The words shall or shall not are used whenever a requirement is intended to express a provision that is mandatory. Deviation from a shall or shall not requirement for a particular Performance Class may be considered if sufficient technical rationale / objective evidence (OE) is supplied to the USER to justify the exception.

b. SHOULD / MAY. The words should and may are used whenever a requirement is intended to express a provision that is non-mandatory, and which reflects general industry practice and / or procedure.

c. WILL. The word will is used to express a declaration of purpose and is intended to express an action that is mandatory.

1.3.1 REQUIREMENT FORMAT (A/N)

To assist the USER, each requirement is identified by its Performance Classification (x1x2x3) and applicability, where “x” represents:

N = No requirement has been established for this Class

A = Applicable

Examples:

[A1A2A3] is Applicable for all Classes

[N1N2A3] is Not Established Class 1 and Class 2, and Applicable Class 3

[N1N2N3] is Not Established for all Classes

Applicability for a Class 1 product means that the characteristic is also applicable for Class 2 and 3. A applicability for a Class 2 product means that the characteristic is also applicable for a Class 3 product, but may not be applicable for a Class 1 product where less demanding criteria may apply.

1.3.2 LINE DRAWINGS AND ILLUSTRATIONS

Line drawings and illustrations are depicted herein to assist in the interpretation of the written requirements of this standard. The written requirement always takes precedence over the drawings and illustrations.

1.4 MEASUREMENT UNITS AND APPLICATIONS

All dimensions and tolerances, as well as other forms of measurement in this standard are expressed in SI (System International) units (with Imperial English equivalent dimensions provided in brackets). Dimensions and tolerances use millimeters (mm) as the main form of dimensional expression; micrometers are used when the precision required makes millimeters too cumbersome.

Non-dimensional units, expressed as wire / wire harness / cable diameters (d) are expressed where a numerical dimension is solely dependent on a physical attribute of the hardware (e.g.: wire gauge, harness diameter, etc.). For the purposes of determining conformance to this specification, all specified limits in this standard are absolute limits as defined in ASTM E29.

1.5 DEFINITION OF TERMS

For purposes of this document, the acronyms, abbreviations, and terms used, but in addition to those listed in IPC-T-50, “Terms and Definitions for Interconnecting and Packaging Electronic Circuits” are listed in Section 10 “Definitions and Acronyms”. Specialized definitions and acronyms related to “Red Plague” are listed in Appendix B.

1.6 ENGINEERING DOCUMENTATION

The design engineer is responsible for ensuring that all applicable design details are clearly and completely depicted on the engineering documentation (drawings). Acceptance criteria shall [A1A2A3] be in accordance with IPC/WHMA-A-620 for the particular Product Class, unless otherwise specified by the USER-approved engineering documentation.