1、erA AEROSPACE ,.,- erospace - ARP1870 REV. A RECOMMENDED .-. An SAE International Group PRACTICE Issued 1987-01 Reaffirmed 1999-04 Stabilized 2012-08 Superseding ARP1870 Aerospace Systems Electrical Bonding and Grounding for Electromagnetic Compatibility and Safety RATIONALE The document is still a
2、valid standard which may benefit from a future update. The basic technology described in the document is still valid. The subcommittee designated to update the document is not currently active, so stabilization of the document is the best approach until such time as a committee can be established to
3、 open a WIP. STABILIZED NOTICE This document has been declared “Stabilized“ by the SAE AE-4, Electromagnetic Environmental Effects (E3) Committee and will no longer be subjected to periodic reviews for currency. Users are responsible for verifying references and continued suitability of technical re
4、quirements. Newer technology may exist. SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including
5、 any patent infringement arising therefrom, is the sole responsibility of the user. SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2012 SAE International A
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8、ded by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP1870A Page 1 of 57 TABLE OF CONTENTS 1. SCOPE . 4 1.1 Purpose . . 4 1.2 General 4 2. REFERENCE DOCUMENTS . . 4 3. DEFINITIONS . 5 4. GENERAL BONDING AND GROUNDING GUIDANCE . 6 4
9、.1 Electrical Bonding . . . . 6 4.1.1 Bond Effectiveness 6 4.1.2 Precedence . . 6 4.2 Grounding . . 7 4.3 Earthing of Aircraft and Ground Services . 7 4.4 Design Requirements . . 7 4.5 Types of Electrrical Bonds . . . 9 4.5.1 Direct Electrical Bonds . 9 4.5.2 Indirect Electrical Bonds 9 4.6 Bonding
10、Straps . . . 10 4.6.1 Characteristics of Individual Bonding Straps . . 10 4.6.2 Characteristics of Bonding S1rap Installations . . 11 4. 7 Bonding Jumpers . 11 4.8 Bonding Metal and Finish Selection 12 4.9 I ntermetallic Contact 12 Copyright SAE International Provided by IHS under license with SAENo
11、t for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP1870A Page 2 of 57 TABLE OF CONTENTS (Continued) 5. DETAIL REQUIREMENTS 13 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.8.1 5.8.2 5.8.3 5.8.3.1 5.8.4 5.9 5.9.1 5.9.2 5.10 5.11 5.12 5.13 5.13.1 Aluminum Surface Preparation 1
12、3 Magnesium Alloy Surface Preparation . 14 Steel Surface Preparation . . . . 14 Structural Metallic Parts . 14 Refinishing . 14 Conductive Paste . 15 Electrical Bonding Methods 15 Bonding Antenna Installations 16 Impedance . 16 Bonding Resistance . 16 Return Path . . 16 Alternate Retl.!lrn Path 16 L
13、ightning Paths 16 Electrical Grounding . 17 Methods of Grounding or Bonding . 17 Cross-Sectional Consideration . 17 Lightning Bonding Considerations . 18 Composite Bonding 18 Nonmetallic Parts . 18 Measuring Bond Resistance/Reactance 19 Shock and Fir,e Safety 19 6. QUALITY ASSURANCE PROVISIONS 20 6.
14、1 6.2 6.3 6.4 TABLE 1 TABLE 2 TABLE 3 CHART1 In-Progress Inspection . 20 Final Inspection 20 Inspection Responsibility . . 20 Inspector Certification 20 Direct Current Resistance Limits for Electrical Bonding . 21 Compatible Couples . . . 22 Fasteners, Hardware . . 23 Fault Current Versus Maximum Al
15、lowed Resistance for Bonding Between Equipment and Structure . 24 Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP1870A Page 3 of 57 TABLE OF CONTENTS (Continued) FIGURE 1 Typical Bolted Conne
16、ction- Blind Plate Stud Terminals . 25 FIGURE 2 Typical Bolted Connection . . 26 FIGURE 3 Typical Grounding Stud . . 27 FIGURE 4 Typical Clamp Connection . 28 FIGURE 5 Typical Method of Bonding Tubing Across Clamps . . 29 FIGURE 6 Preparation of Bonding Connection in Bolted Structural Joints 30 FIGU
17、RE 7 Method of Bonding by Means of Fasteners . 31 FIGURE 8 Method of Bonding Edge Lighted Panels . 32 FIGURE 9 Method of Bonding Between Structural Parts in an Assembly . 33 FIGURE 10 Method of Bonding Through Bolted Connection Requiring Sealant . 34 FIGURE 11 Method of Bonding Between Structural Pa
18、rts of an Assembly Requiring s,ealant . 35 FIGURE 12 Typical Bonding Tap to Structure . . 36 FIGURE 13 Typical Electrical Bonding of Details Which are Electrically Isolated by Adhesives . 37 FIGURE 14 Typical Bonding When Blind Rivet Nut is Used . . 38 FIGURE 15 Methods of Bonding Connectors to Atta
19、ching Part 39 FIGURE 16 Methods of Bonding Connectors to Attaching Part . .40 FIGURE 17 Methods of Bonding Metal Connectors to Attaching Part . . 41 FIGURE 18 Method of Bonding Equipment Installed on Vehicle Structure With Mounting Feet . 42 FIGURE 19 Electrical Bonding of Junction Block Assemblies
20、to Attaching Part . 43 FIGURE 20 Method of Bonding Circuit Breakers to Circuit Breaker Panel . 44 FIGURE 21 Methods of Bonding Electronic Equipment to Mount Through Front Attachments .45 FIGURE 22 Method of Bonding Electronics Packages to Rack Through Front Attachments . .46 FIGURE 23 Method of Bond
21、ing Electronic Packages Through Dagger Pins . .47 FIGURE 24 Method of Bonding Between Attaching Flange of Electronic Package and Rack . .48 FIGURE 25 Method of RF Bonding Access Doors and Panels .49 FIGURE 26 Method of Installation of Bonding Straps on Shock Mounts . 50 FIGURE 27 Method of Bonding A
22、ntenna . 51 FIGURE 28 Method of Bonding Static Discharger Assembly to Exterior of Aircraft 52 FIGURE 29 Methods of Measuring Bonding Resistance . 53 FIGURE 30 Methods of Verifying the Bonding Assemblies or Units 54 FIGURE 31 Resistance Versus Frequency Plot of Equal Length Bond Conductors . 55 FIGUR
23、E 32 Plot Comparing Relative Magnitudes of Resistive and Inductive Components of Wire Impedance . , . 56 FIGURE 33 Equations for Bond Strap Design . 57 Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,
24、-SAE ARP1870A Page 4 of 57 1. SCOPE: 1 .1 Purpose: This document establishes the minimum requirements for the electrical bonding and grounding of electric, avionic, armament, communication, and electronic equipment installations for aeronautical and aerospace applications. The bonding and grounding
25、requirements specified herein are to ensure that an adequate low resistance return path for electric, avionic, armament, communication and electronic equipment is achieved which can withstand operating conditions and corrosion. This is essential for the reduction of coupling of electromagnetic field
26、s into or out of the equipment as well as for providing electrical stability to control the currents and/or voltages caused by static charges and discharges and for suppressing the hazardous effects thereof. 1.2 General: A prerequisite to effective control of electromagnetic interference (EM I) and
27、the hazards of electrical effects is the establishing of a reference ground plane and the means of providing adequate connections to it. Making a connection to the ground plane is grounding, and the mechanical method of providing a low impedance union between conductors is electrical bonding. 2. REF
28、ERENCE DOCUMENTS: The following documents, of the issue in effect on date of invitation for bids or request for proposal, form a part of this standard to the extent specified herein. Standards Ml L-STD-889 MIL-STD-1250 MIL-STD-1757 Specifications MIL-M-3171 MIL-B-5087 MIL-S-5002 MIL-C-5541 Ml L-E-60
29、51 D MIL-C-7439 MIL-1-46058 MIL-T-83454 Dissimilar Metals Corrosion Prevention and Deterioration Control in Electronic Components and Assemblies Lightning Qualification Test Techniques for Aerospace Vehicles and Hardware Magnesium Alloys, Processes for Pretreatment and Prevention of Corrosion on Bon
30、ding, Electrical and Lightning Protection, for Aerospace Systems Surface Treatments and Inorganic Coatings for Metal Surfaces of Weapons Systems Chemical Conversion Coatings on Aluminum and Aluminum Alloys Electromagnetic Compatibility Requirements, Systems Coating System Elastomeric Rain Erosion Re
31、sistant and Rain Erosion Resistant with Anti-Static Treatment for Exterior Aircraft and Missile Plastic Parts Insulating Compound, Electrical (for Coating Printed Circuit Assemblies) Terminals, Stud, Blind Plate, for Electrical Bonding and Grounding (Noninsulated) Copyright SAE International Provide
32、d by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP1870A Page 5 of 57 2. (Continued): TT-L-32 Lacquer, Cellulose Nitrate, Gloss for Aircraft Use TT-L-20A Lacquer, Camouflage MS 25083 Jumper Assembly, Electric, Bonding and Current
33、Return NATO Stanag 3859 Standardized Data List for lnteroperability Studies and Certification of Aircraft Stores on Fixed Wing Aircraft and Helicopters DH1-4 Design Handbook, Electromagnetic Compatibility Military Handbook Military Handbook- Electrical Grounding for Aircraft Safety Ml L-HDBK-27 4 (A
34、S) Miscellaneous Publications ASCC 12/24 SAE ARP1481 NASA RP-1 008 FAA AC 20-53 () SCAR D4-6 3. DEFINITIONS: Air Standardization Coordinating Committee Document Corrosion Control and Electrical Conductivity in Enclosure Design Lightning Protection of Aircraft Protection of Aircraft Fuel Systems Agai
35、nst Lightning Electrical Bonding and Lightning Discharge Protection For the purpose of this specification, the following definitions are applicable: Bond - An electrical connection between conductive parts which provides the required electrical conductivity. Bonded -Conductive parts that are conside
36、red to be bonded when they are mechanically interconnected to maintain a common electrical potential. Equipotential- For alii practical purposes, an identical state of electrical potential for conducting item(s). Equipment- Any electrical, electronic or electromechanical device, or collection of ite
37、ms, intended to operate as an individual unit and performing a singular function. As defined herein, equipments include, but are not limited to, the following: receivers, transmitters, transceivers, transponders, power supplies, electrical office machines, hand tools, processors, test apparatus and
38、instruments, and material handling eq11.1ipment. Ground - A conducting connection, whether intentional or accidental, by which an electric current or equipment is connected to the earth, or to a conducting structure that serves a function similar to that of an earth ground (that is, a structure such
39、 as a frame of an air, space or land vehicle that is not conductively connected to earth). Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP1870A Page 6 of 57 3. (Continued): Ground Plane-A sur
40、face, all points of which are assumed to be at the same potential, usually the zero reference potential for the system. (Note: A true, equipotential ground plane does not exist in practice. The deviations from the ideal increase with the frequency of the signals appearing on the ground plane conduct
41、or and can become a very important consideration in system design.) 4. GENERAL BONDING AND GROUNDING GUIDANCE: 4.1 Electrical Bonding: Electrical bonding is the process employed to obtain an electrical union between conductors that meets specified requirements. This can be accomplished mechanically
42、by connecting cleaned metal parts together by use of such techniques as bolts, rivets or welding. Electrical bonding is required to minimize electrical potential differences between individual metal parts for all voltages and frequencies capable of causing interference. 4.1.1 Bond Effectiveness: The
43、 effectiveness of a bond at radio frequencies is neither fully dependent upon nor measurable only in terms of its DC electrical resistance. This is especially true at high frequencies, wherre lengths of bonding devices tend to approach the wavelengths of undesirable electromagnetic radiation. DC mea
44、surement is an indication of very low-frequency bonding effectiveness. At high frequencies, however, bond effectiveness may be determined by means of impedance measurements because bond capacitance and inductance become significant and will cause high RF bond impedances, despite low DC resistance re
45、adings. In practice, DC resistance measurements may be utilized to detect grossly defective bonds and to determine quickly, by comparison with manufacturers test data, whether or not bonds on existing equipment have deteriorated. In general, the effectiveness of an electrical bond for a given purpos
46、e depends on the characteristics of its application such as frequency range, magnitude of current passing through it, and environmental conditions such as vibration, temperature, humidity, fungus, and salt content in the ambient. 4.1.2 Precedence: In case of conflict between corrosion control requir
47、ements and electromagnetic compatibility (EMC) electrical bonding requirements, it is imperative that the conflict be resolved to the mutual satisfaction of all parties. This resolution should be reached as early in the design process as practical. In the event of a compromise between EMC and corros
48、ion protection requirements, continuing maintenance instructions should be written to ensure any necessary periodic inspection and service or treatment of the affected bond(s). Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted wit
49、hout license from IHS-,-,-SAE ARP1870A Page 7 of 57 4.2 Grounding: Electrical grounding is accomplished by establishing a minimum series impedance path between the electrical equipment and the ground plane. A ground is used to establish a zero signal reference for any equipment or other item required to be grounded. On metal vehicles, the metal frame should
