Attachment 6 TO-31-10-24.PDF

(USAF) T.O. 31-10-24

(ARMY) ARMY FM 11-487-4

TECHNICAL MANUAL

INSTALLATION PRACTICES: COMMUNICATIONS

SYSTEMS GROUNDING, BONDING, AND SHIELDING

(ATOS)

GS-23F-0129L

THIS MANUAL SUPERSEDES T.O. 31-10-24, DATED 28 DECEMBER 1987, AND ALL SUBSEQUENT CHANGES.

DISCLOSURE NOTICE: This information is furnished upon the condition that it will not be released to another nation without the specific authority of the Department of the Air Force of the United States, that it will be used for military purposes only, that individual or corporate rights originating in the information, whether patented or not, will be respected, that the recipient will report promptly to the United States, any known or suspected compromise, and that the information will be provided substantially the same degree of security afforded it by the Department of Defense of the United States. Also, regardless of any other markings on the document, it will not be downgraded or declassified without written approval of the originating United States agency.

DISTRIBUTION STATEMENT C: Distribution authorized to U.S. Government agencies and their contractors, Administrative or Operational Use, 20 May 1997. Refer Other requests shall be referred to 420 SCMS/GULAB, Tinker AFB, OK 73145-3029.

WARNING: This document contains technical data whose export is restricted by the Arms Export Control Act (Title 22, U.S.C. 2751 et seq.) or the Export Administration Act of 1979, as amended, Title 50, U.S.C., App. 2401, et seq. Violation of these export-control laws is subject to severe criminal penalties. Dissemination of this document is controlled under DoD Directive 5230.25.

HANDLING AND DESTRUCTION NOTICE: Destroy by any method that will prevent disclosure of contents or reconstruction of the document.

Published under authority of the Secretary of the Air Force

15 NOVEMBER 2011

Attachment 6

T.O. 31-10-24

ARMY FM 11-487-4

INSERT LATEST CHANGED PAGES. DESTROY SUPERSEDED PAGES.

LIST OF EFFECTIVE PAGES

NOTE: The portion of the text affected by the changes is indicated by a vertical line in the outer margins of the page. Changes to illustrations are indicated by shaded or screened areas, or by miniature pointing hands.

Dates of issue for original and changed pages are:

Original . . . . . . . . . . . . . . . . . . . . 0 . . . . . . . 15 November 2011

TOTAL NUMBER OF PAGES IN THIS MANUAL IS 324, CONSISTING OF THE FOLLOWING:

Page *Change Page *Change Page *Change No. No. No. No. No. No.

Title A i - vii viii Blank ix - x 1-1 1-2 Blank 2-1 - 2-8 3-1 - 3-2 4-1 - 4-19 4-20 Blank 5-1 - 5-57 5-58 Blank 6-1 - 6-18 7-1 - 7-66 8-1 - 8-34 9-1 - 9-25 9-26 Blank 10-1 - 10-14 A-1 - A-3 A-4 Blank B-1 - B-24 C-1 - C-20 D-1 - D-5 D-6 Blank E-1 - E-4 Index 1 - Index 5 Index 6 Blank

*Zero in this column indicates an original page

A USAF

TABLE OF CONTENTS

Chapter Page Chapter Page

INTRODUCTION......................................................vii 5.4 Tools .........................................................5-13

5.5 Preparing Cables for Termination ...........5-13

SAFETY SUMMARY................................................ix SECTION III INSTALLATION OF

SHIELDED ENCLOSURES .............................5-25

1 GENERAL INFORMATION...................................1-1 5.6 General......................................................5-25

5.7 Shielding Effectiveness ............................5-25

1.1 General........................................................1-1 5.8 Multiple Shields........................................5-28

5.9 Construction Methods...............................5-30

2 SAFETY AND FIRST AID .....................................2-1 5.10 Shielding Materials and Gaskets..............5-31

5.11 Sealing Seams and Apertures...................5-43

2.1 Safety ..........................................................2-1

2.2 First Aid......................................................2-2 6 INSTALLATION OF EARTH ELEC-

TRODE SUBSYSTEMS......................................6-1

3 GROUNDING...........................................................3-1

6.1 General........................................................6-1

3.1 General........................................................3-1 6.2 Types of Earth Electrodes..........................6-1

3.2 Facility Ground System..............................3-1 6.2.1 Ground Rods...............................................6-1

3.2.1 The Earth Electrode Subsystem.................3-1 6.3 Factors Affecting the Impedance

3.2.2 The Lightning Protection Subsys- of an Earth Electrode Subsys-tem..........................................................3-1 tem........................................................6-12

3.2.3 The Fault Protection Subsystem ................3-1 6.4 Interconnections and Bonds .....................6-14

3.2.4 The Signal Reference Subsystem...............3-1 6.5 Tools and Materials..................................6-14

3.3 Relationship Among Subsystems...............3-2 6.6 Chemicals and Inert Backfills ..................6-15

4 BONDING ................................................................4-1 7 INSTALLATION PRACTICES FOR

LIGHTNING PROTECTION SUB-

4.1 General........................................................4-1 SYSTEMS ............................................................7-1

4.2 Bond Impedance Requirements .................4-1

4.3 Types of Bonds...........................................4-1

4.4 Direct, Permanent Bonds............................4-1 SECTION I INTRODUCTION..............................7-1

4.5 Welding Procedures....................................4-1

4.6 Brazing Procedures.....................................4-2 7.1 Components of the Lightning

4.7 Exothermic Welding Procedures................4-3 Subsystem ..............................................7-1

4.8 Soldering Procedures..................................4-4 7.2 Direct-Strike Protection..............................7-2

4.9 Direct, Semipermanent Bonds....................4-4 7.3 Lightning Protection Hardware..................7-3

4.10 Cleaning and Refinishing Bonded 7.4 Air Terminals..............................................7-3

Surfaces ..................................................4-7 7.5 Overhead Ground Wires.............................7-4

4.11 Bonding Straps .........................................4-10 7.6 Down Conductors .......................................7-4

4.12 Corrosion of Dissimilar Materials ...........4-11 7.7 Surge Protection .........................................7-6

4.13 Specific Applications................................4-11

SECTION II SPECIFIC APPLICA-

5 SHIELDING..............................................................5-1 TIONS ................................................................7-20

7.8 Lightning Protection for Towers

SECTION I INTRODUCTION..............................5-1 and Antennas........................................7-20

7.9 Lightning Protection for

5.1 General........................................................5-1 Waveguide and Cable..........................7-27

5.2 Shielding Buildings and Rooms.................5-1 7.10 Lightning Protection for Outside

Plant .....................................................7-35SECTION II CABLE SHIELDING.......................5-1

7.11 Lightning Protection for Perime-

ter Fences .............................................7-475.3 General........................................................5-1 i

8 INSTALLATION PRACTICES FOR 10.3 Fault Protection Subsystems for FAULT PROTECTION SUBSYS- Transportable Equipment.....................10-1 TEMS AND POWER DISTRIBU- 10.4 Grounding of Transportable TION SYSTEMS .................................................8-1 Equipment at a Fixed Facility.............10-4

10.5 Protection of Mobile Equipment

in Remote Locations............................10-8

SECTION I FAULT PROTECTION 10.6 Lightning Protection for Trans- SUBSYSTEMS ....................................................8-1 portable Equipment..............................10-8

10.7 Van Grounding Networks ........................10-8

8.1 General........................................................8-1

8.2 Grounding Service Entrances and A REFERENCES.........................................................A-1

Distribution Panels.................................8-1

8.3 Conduit and Raceway Installation ...........8-11 A.1 Cited Documents .......................................A-1

8.4 Installing Fault Protection Con- A.2 Related Documents....................................A-2 ductors in Racks and Cabinets ...........8-17 B TESTS AND MEASUREMENTS ..........................B-18.5 Bonding Equipment to a Fault

Protection Subsystem...........................8-21 B.1 Earth Electrode Resistance-To-8.6 Controlling Static Discharges...................8-21

Ground Measurements..........................B-1 SECTION II GROUNDING POWER B.2 Earth Ground Resistivity Mea-

DISTRIBUTION SYSTEMS.............................8-21 surements ..............................................B-7 B.3 Measuring AC Currents in

8.7 General......................................................8-21 Ground Conductors...............................B-9

8.8 Grounding AC Power Distribu- B.4 Measuring DC Currents in tion Systems.........................................8-21 Ground Conductors.............................B-12 Table Typical Voltages for Given B.5 AC and DC Voltage Measure-

8-1 Transformer Connections ....................8-23 ments ...................................................B-13

8.9 AC Power Wiring.....................................8-24 B.6 AC Phase Load Measurements ...............B-14

8.10 AC Power Distribution Require- B.7 Proper AC Waveform..............................B-15 ments ....................................................8-24 B.8 Transient or Recurring Electrical

8.11 AC Power Line Filters .............................8-25 Noise on AC Power Supply

8.12 Distribution of AC Power from Lines....................................................B-15

Multiple Sources ..................................8-25 B.9 DC Power Source Ripple and

8.13 Grounding DC Power Distribu- Wideband Noise Measure-

tion Systems.........................................8-26 ments ...................................................B-16 B.10 Wideband Noise Measurements..............B-19

9 INSTALLATION PRACTICES FOR B.11 Testing of Shielded Enclosures SIGNAL REFERENCE SUBSYS- (General) .............................................B-22 TEMS ...................................................................9-1 B.12 National Security Agency Speci-fications 65-5 and 65-6.......................B-23

9.1 General........................................................9-1 B.13 MIL-STD-462 Testing.............................B-24

9.2 General Installation Practices for

Signal Reference Grounds.....................9-6 C POWER SYSTEM WIRING, COLOR Table Straps and Wires for the Signal CODES, RECEPTACLES, CORDS, 9-1 Reference Subsystem.............................9-6 AND PLUGS ......................................................C-1

9.3 Installation Practices for Single-

Point Signal Reference Sub- C.1 AC Power Wiring Color Codes ................C-1 systems .................................................9-13 C.2 Wiring of U.S.A. 120-Vac Out-

9.4 Installation of Multipoint Signal lets and Plugs........................................C-2 Reference Subsystems .........................9-13 C.3 Wiring of Germain Din 220-Vac

Outlets and Plugs..................................C-2 10 INSTALLATION PRACTICES FOR C.4 Wiring of 220-Vac Grounding

GROUNDING TRANSPORTABLE Receptacles in Spain.............................C-4 FACILITIES.......................................................10-1 C.5 Standard AC Power Frequencies and Voltages Throughout the

10.1 Transportable Power Distribution World by Geographic Area

Systems ................................................10-1 Listed in Table C-2...............................C-5

10.2 Conductors for Transportable Fa- C.6 International Plug Configurations ............C-7 cilities ...................................................10-1 ii

C.7 Conductor Types......................................C-10 E GLOSSARY............................................................. E-1 C.8 Current Carrying Capacity for

Copper Conductors .............................C-14 E.2 Definitions.................................................. E-2 C.9 DC Power Wiring Codes ........................C-18

INDEX .............................................................. Index 1

D METRIC TABLES ..................................................D-1

D.1 Tables.........................................................D-1

LIST OF ILLUSTRATIONS

Number Title Page Number Title Page

2-1 Ground Warning Tag...................................... 2-1 5-11 Triaxial Cable Terminated at a Combin- 2-2 Shorting Probe ................................................ 2-2 er Panel..................................................... 5-15 2-3 Temporary Safety Bonding Strap................... 2-3 5-12 Triaxial Cable Terminated at Equipment 2-4 Mouth-to-Mouth Resuscitation....................... 2-4 with Coaxial Input ................................... 5-17 2-5 Back-Pressure-Arm-Lift Resuscitation........... 2-6 5-13 Installation of a Shielded Isolation 4-1 Typical Permanent Bonds............................... 4-2 Transformer .............................................. 5-18 4-2 Typical Exothermic Weld Molds and 5-14 Installation of Improved Coaxial BNC

Wire Placement .......................................... 4-6 Cable Connectors ..................................... 5-21 4-3 One-Shot Exothermic Weld............................ 4-7 5-15 Grounding of Overall Cable Shields to 4-4 Typical Mechanical Bonds ............................. 4-8 Connectors and Penetrated Walls ............ 5-24 4-5 Compression Tools for Pressure Bonds......... 4-9 5-16 Grounding of Overall Cable Shields to 4-6 Typical Crimp-Type Connections .................. 4-9 Terminal Strips......................................... 5-25 4-7 An Improper Rivet Seam.............................. 4-10 5-17 Compression Ring Power Tool and Hy- 4-8 Typical Rivets and Their Dimensions.......... 4-10 draulic Pump ............................................ 5-26 4-9 Typical Flat Strap Installation ...................... 4-12 5-18 Single-fold, Multishield Ground Meth- 4-10 Typical Round Strap Installation.................. 4-13 ods............................................................. 5-27 4-11 Bonding Straps on Shock-Mounted 5-19 Double-Fold, Multishield Ground Meth-

Equipment................................................. 4-13 ods............................................................. 5-29 4-12 Exothermic Welds to Ground Conduc- 5-20 Termination of Shielded Multipair tors ............................................................ 4-16 Cables ....................................................... 5-30 4-13 Clamped and Braced Ground Rod Con- 5-21 Attaching an Extension Wire to the nection ...................................................... 4-18 Shield of a Twinaxial Cable (Crimp- 4-14 Ground Damps .............................................. 4-19 type Connection) ...................................... 5-31 5-1 Typical Shielded Cables ................................. 5-2 5-22 Termination of Cable Shields by Col- 5-2 Grounding a Long Lower Frequency lective Crimping....................................... 5-32

Cable........................................................... 5-4 5-23 Termination of Shielded Conductors 5-3 Grounding a Long Higher Frequency with Grounding Sheaths........................... 5-34

Cable........................................................... 5-5 5-24 Maintaining Shield Integrity of Mul- 5-4 Installation of Unimproved Coaxial tipair Cables through a Terminal or

BNC Cable Connectors.............................. 5-7 Junction Box............................................. 5-35 5-5 Installation of Polarized Twinaxial 5-25 Installation of a Separate Signal Refer-

Cable Connectors ....................................... 5-8 ence Conductor for a Network of 5-6 Grounding a Double-Shielded Coaxial Voice Frequency Cable Shields............... 5-36 or Triaxial Cable for Higher and 5-26 Simplified Signal Reference Network Lower Frequencies ..................................... 5-9 for Voice Frequency and High-Level

5-7 Installation of Concentric Triaxial Cable TTY Shields ............................................. 5-37 connectors................................................. 5-10 5-27 Basic Types of Shielded Enclosures ............ 5-38

5-8 Attaching an Extension Wire to the 5-28 Typical Shielded Enclosure Hardware ......... 5-39 Shield of a Coaxial Cable (Crimp- 5-29 Optional Inside-Bolted Construction Type Connection)..................................... 5-11 (Double Wall)........................................... 5-39

5-9 Establishing Shield Continuity Between 5-30 Installation of Finger Stock in a Higher Frequency Equipment.................. 5-12 Shielded Enclosure Door ......................... 5-40

5-10 Preparation of Shielded Conductors............. 5-14 5-31 Details of a Rigid Grid Floor System.......... 5-42 iii

5-32 Bolted Connection Between a Rigid 7-11 Lightning Conductor Installed with Grid and an Pedestal ................................ 5-43 Wood Crew Extension Fastener .............. 7-13

5-33 Clamped Connection Between a Rigid 7-12 Masonry Anchors.......................................... 7-14 Grid and a Pedestal .................................. 5-44 7-13 Lightning Protection Subsystem for a

5-34 Attenuation Characteristics of Building .................................................... 7-15 Waveguide Operating Beyond Cutoff ..... 5-45 7-14 Typical Surge Protection Devices ................ 7-17

5-35 Buckling of Thin Material Between 7-15 Installation of Gas-Tube Protective De- Fasteners ................................................... 5-45 vices on a Panel or an Equipment

5-36 Method of Forming a Seam in a Screen Cabinet...................................................... 7-19 Enclosure .................................................. 5-46 7-16 Lightning Arrester Installation on a

5-37 Typical Groove-Type Gaskets and Ap- Branch Power Distribution Panel ............ 7-21 plications................................................... 5-48 7-17 Typical Connector Assembly and Pro-

5-38 Typical Conductive Gasket Applica- tective Module (Older Style) ................... 7-25 tions .......................................................... 5-49 7-18 Typical Connector Assembly with Inte-

5-39 Typical Conductive Caulking Applica- gral Protectors (Modern Style) ................ 7-26 tions .......................................................... 5-50 7-19 Protected Ready-Access Cable Terminal ..... 7-28

5-40 Permanent Seams Made from rf Gas- 7-20 Typical Lightning Arrester Connections ..... 7-29 kets............................................................ 5-51 7-21 Lightning Protection for a Guyed Tow-

5-41 Technique for Shielding Air Vents with er ............................................................... 7-30 Honey-Comb Filters................................. 5-51 7-22 Grounding Connection for a Guyed

5-42 Installation of Air Filters over Large Tower........................................................ 7-31 Apertures .................................................. 5-52 7-23 Earth Electrode Subsystem for a Guyed

5-43 Sealing Small Apertures ............................... 5-54 Tower........................................................ 7-32 5-44 Shielding of Transparent Openings in 7-24 Lightning Protection for a Guyed Tow-

Enclosures................................................. 5-56 er Insulated from Ground ........................ 7-33 5-45 Rf gaskets for Doors and Covers ................. 5-57 7-25 Lightning Protection for a Self-Support- 6-1 Typical Earth Electrode Subsystem ............... 6-3 ing Tower ................................................. 7-34 6-2 Typical Ground Rods...................................... 6-4 7-26 Grounding a Tower Leg ............................... 7-37 6-3 Typical Resistance Readings for 7-27 Typical Horn-Gap/Gas-Gap Lightning

Ground Rods at Various Depths ............... 6-6 Arrester ..................................................... 7-38 6-4 Typical Ground Rod Installations .................. 6-7 7-28 Lightning Protection for a Roof-Mount- 6-5 Locally Fabricated Hammer for Driving ed Antenna ............................................... 7-40

Ground Rods .............................................. 6-8 7-29 Grounding of Waveguide and Support- 6-6 Radial Horizontal Wires Used as Elec- ing Structures ........................................... 7-41 trodes ........................................................ 6-10 7-30 Grounding of Waveguide at the Transi- 6-7 Typical Ring Ground and Connections........ 6-11 tion Point .................................................. 7-43 6-8 Typical Star Ground and Connections ......... 6-13 7-31 Preferred Method of Grounding Ellipti- 6-9 Concrete-Encased Rebars Used as Earth cal Waveguide at an Entry Port

Electrodes ................................................. 6-14 (Front View)............................................. 7-44 6-10 Soil Resistivity Versus Moisture Con- 7-32 Preferred Method of Grounding Ellipti-tent ............................................................ 6-15 cal Waveguide at an Entry Port 6-11 Soil Resistivity Versus Temperature............ 6-16 (Side View) .............................................. 7-45 6-12 Trench Method of Treating Soil for 7-33 Constructing a Ground Strap from a

Ground Rods ............................................ 6-18 Piece of Elliptical Waveguide ................. 7-48 7-1 Lightning Protection Subsystem..................... 7-2 7-34 Alternative Method of Grounding 7-2 Typical Zones of Protection ........................... 7-3 Waveguide at an Entry Port (Front 7-3 Some Commonly Used Lightning View) ........................................................ 7-49

Shielding Angles ........................................ 7-5 7-35 Alternative Method of Grounding 7-4 Bonding a Metal Projection to the Waveguide at an Entry Port (Side

Lightning Protection Subsystem................ 7-7 View) ........................................................ 7-50 7-5 Lightning Protection Hardware ...................... 7-8 7-36 Waveguide Ground Strap Hardware ............ 7-51 7-6 Typical Air Terminal Mountings ................. 7-10 7-37 Typical Cable Entry Installation .................. 7-52 7-7 Air Terminal Support.................................... 7-10 7-38 Ground Strap for Cables............................... 7-53 7-8 Overhead Ground Wire Lightning Pro- 7-39 Steps for Grounding Cables ......................... 7-54 tection System .......................................... 7-11 7-40 Air-Gap Protector.......................................... 7-55 7-9 Standard and Substandard Practices for 7-41 Drainage Units Mounted on a Crossarm ..... 7-56

Down Conductor Installation................... 7-12 7-42 Protected Terminal, Wall-Mounted.............. 7-57 7-10 Fasteners for Lightning Protection Con- 7-43 Unprotected Terminal, Wall-Mounted ......... 7-58 ductors ...................................................... 7-13 7-44 Grounding a Pole .......................................... 7-59 iv

7-45 Installation of Protective Devices on 9-3 Microwave Radio Signal Reference Open-Wire Circuits .................................. 7-60 Subsystem................................................... 9-4

7-46 Grounded Carrier Protection ........................ 7-61 9-4 Composite Signal Reference Subsystem ....... 9-5 7-47 Bonding Cable Sheaths at the Cable 9-5 Typical Couplers and Clamps Used in

Vault ......................................................... 7-62 the Reference Subsystem........................... 9-7 7-48 Pole-Mounted Installation Grounding 9-6 Signal Reference Conductors Supported

Arrangement ............................................. 7-63 from a Framing Channel............................ 9-8 7-49 Power Equipment Installed Above 9-7 Typical Method of Supporting Signal

Communications Attachments ................. 7-64 Reference Ground Ring and Con- 7-50 Power Equipment Installed Below necting Jumpers.......................................... 9-9

Communications Attachments ................. 7-65 9-8 Cable and Conduit Bonding ......................... 9-11 7-51 Grounding a Fence........................................ 7-66 9-9 Bonding Procedures for Cable Ladders ....... 9-14 8-1 Wiring Diagram for a Fault Protection 9-10 Bonding Procedures for a Bolted Struc-

Subsystem................................................... 8-3 tural Joint.................................................. 9-15 8-2 Fault Protection Subsystem (Simplified) ....... 8-4 9-11 Bonding of Miscellaneous Connections....... 9-15 8-3 Fault Protection Conductors in Duct 9-12 Bonding the Flange of an Electronic and Conduit to Equipment Racks.............. 8-5 Package to a Rack.................................... 9-16 8-4 Ground Connectors at Power Panels.............. 8-6 9-13 Bonding With Dagger Pins .......................... 9-17 8-5 Terminations for Fault Protection Con- 9-14 Bonding to a Structure with Mounting ductors ...................................................... 8-10 Feet ........................................................... 9-17 8-6 Terminating a Fault Protection Conduc- 9-15 Bonding Between Sections of Cable tor in a Box .............................................. 8-11 Trays ......................................................... 9-18 8-7 Fault Protection Conductor External to 9-16 Equipment Cabinets Bonded to a Cable

Conduit ..................................................... 8-13 Tray........................................................... 9-19 8-8 Grounding of Wireways and Cable 9-17 Installing a Ground Bus Insulated from

Ducts......................................................... 8-15 an Equipment Cabinet.............................. 9-20 8-9 Bonding Procedures for an AC/DC and 9-18 Connecting a Signal Reference Conduc-

Signal Duct (Army Only) ........................ 8-16 tor to an Equipment Cabinet ................... 9-21 8-10 Typical Terminals for Grounding Con- 9-19 Typical Ground Bar Mounting..................... 9-22 ductors in the Fault Protection Sub- 9-20 Typical Ground Box ..................................... 9-23 system....................................................... 8-17 9-21 Use of anEquipotential Plane in the

8-11 Routing of Fault Protection Conductors Signal Reference Subsystem.................... 9-24 in a Cabinet .............................................. 8-19 9-22 Typical Bonding Clamps Used in an

8-12 Connecting a Fault Protection Conduc- Equipotential Plane .................................. 9-25 tor to a Flat Metal Surface ...................... 8-20 10-1 Typical Consolidated Power System for

8-13 AC Fault Finder ............................................ 8-21 a Transportable Communications Fa- 8-14 Terminations for Fault Protection Con- cility.......................................................... 10-2 ductors in Rack-Mounted Equipment ..... 8-22 10-2 Bonded Shock Mount ................................... 10-3 8-15 Connecting a Fault Protection Conduc- 10-3 Typical Power Entrance Panel ..................... 10-4 tor to Equipment Without a Ground 10-4 Typical 3-Wire Power Cable Connector Terminal ................................................... 8-23 and Receptacle Assembly ........................ 10-6

8-16 Terminal Lugs for Rack-Mounted 10-5 Typical 5-Wire Power Cable Connector Equipment................................................. 8-25 and Receptacle Assembly ........................ 10-7

8-17 Bonding Adjacent Racks .............................. 8-26 10-6 Typical Ground Rod for Mobile C-E 8-18 Protective and Neutral Wiring for a Equipment................................................. 10-9

Single Feed, 480/277 and 208/120 10-7 Installation of a Ground Rod for Mobile Vac System............................................... 8-28 Equipment............................................... 10-10

8-19 Typical Branch Circuit Wiring..................... 8-29 10-8 Overall View of a Transportable Facili- 8-20 Example of Had Balancing .......................... 8-30 ty and Grounded Equipment.................. 10-11 8-21 Typical Power Filters.................................... 8-31 10-9 Grounding of a SATCOM Terminal in 8-22 Filter Installation........................................... 8-32 Areas of High Lightning Activity ......... 10-13 8-23 Typical 4-Wire Battery Facility ................... 8-33 10-10 Typical Site Ground Field .......................... 10-14 8-24 Typical Floor Plan of a DC Power Fa- B-1 Fall-of-Potential Method for Measuring cility.......................................................... 8-34 Ground Resistance .....................................B-2 9-1 Single-Point Signal Ground (For Lower B-2 Curve of Ground Resistance Versus

Frequencies) ............................................... 9-2 Distance ......................................................B-3 9-2 Multipoint Signal Ground (For Higher B-3 Comparison Method of Measuring

Frequencies) ............................................... 9-3 Ground Resistance .....................................B-4 v

B-4 Triangulation Method of Measuring B-14 Test Setup for Measuring Wideband Ground Resistance .....................................B-4 Noise on Equipment.................................B-20

B-5 Test Data Sheet - Station Ground Resis- B-15 Test Data Sheet - Wideband Noise on tance............................................................B-6 Equipment (with Respect to Earth

B-6 Measuring Earth Resistivity ...........................B-7 Ground).....................................................B-21 B-7 Test Data Sheet - Earth Ground Resis- B-16 Measuring Connector Bond Resistance .......B-22 tivity Measurement...................................B-10 C-1 Wiring of U.S.A. 120-Vac Outlets.................C-2 B-8 Test Data Sheet - AC Currents in C-2 Wiring of U.S.A. 120-Vac Plugs ...................C-2

Ground Conductors ..................................B-11 C-3 Wiring of DIN 220-Vac Schucko Out- B-9 Test Data Sheet - DC Currents in lets...............................................................C-3

Ground Conductors ..................................B-13 C-4 Wiring of DIN 220-Vac Schucko Plugs .......C-3 B-10 Test Data Sheet - AC and DC Voltages .....B-14 C-5 Correct Wiring of Modified U.S.A.

B-11 Test Setup for Measuring AC 220-Vac Polarized Grounding Re-

Waveform Distortion and Transient ceptacles .....................................................C-4 Noise on AC Power Lines.......................B-16 C-6 Spanish 220-Vac Polarized Grounding

B-12 Test Setup for Measuring Voltage and Receptacles .................................................C-4 Output Ripple and Wideband Noise C-7 Selected International Plug Configura-from Battery Facilities or Power tions ............................................................C-9 Supplies ....................................................B-17 C-8 Selected International Approval Agency

B-13 Test Data Sheet - Ripple and Wideband Marks........................................................C-10 Noise.........................................................B-19

LIST OF TABLES

Number Title Page Number Title Page

2-1 Probable Effects of Electric Shock................... 2-2 9-2 Typical Signal Reference Subsystem 4-1 Exothermic Weld Materials .............................. 4-5 Hardware..................................................... 9-10 4-2 Protective Tapes and Coatings for Bonds ..... 4-10 A-1 Military Publications........................................ A-1 4-3 Metal Connections for Bonding Straps .......... 4-14 A-2 Nonmilitary Publications ................................. A-2 4-4 Corrosion Potentials for Various Metals........ 4-15 A-3 Military Publications........................................ A-2 5-1 Tools and Materials for Assembling A-4 Nonmilitary Publications ................................. A-3

Cables and Connectors............................... 5-13 B-1 Guide to the Approximate Location of 5-2 Connector Application Summary ................... 5-22 the Potential Reference Probe, P2, and 5-3 Selecting Ring Size......................................... 5-23 the Current Reference Probe, C2.................B-2 5-4 Shielding Materials ......................................... 5-32 B-2 Resistivities of Various Soils............................B-8 5-5 Characteristics of Conductive Seals and C-1 Standard Frequencies and Voltages by

Gaskets........................................................ 5-40 Geographic Area...........................................C-5 6-1 Advantages and Disadvantages of Types C-2 Metric Wire Sizes and AWG Equivalents of Electrodes................................................. 6-2 for Equipment Power Cords ........................C-8 6-2 Tools for installing Earth Electrode Sub- C-3 Insulated Conductors.......................................C-11 systems........................................................ 6-16 C-4 Power Cables...................................................C-13 7-1 Typical Lightning Protection Hardware ........... 7-4 C-5 Current-Carrying Capacities for Copper 7-2 Typical Surge Protection Devices .................. 7-16 Conductors in Raceway or Cable ..............C-15 7-3 Materials for Installing Waveguide C-6 Current-Carrying Capacities for Single

Ground Connections................................... 7-35 Copper Conductors in Free Air .................C-17 7-4 Minimum Vertical Separations Between C-7 Correction Factors for Table C-6 and Ta-

Power and Communications Attach- ble C-7 for Temperatures Over 30°C ments........................................................... 7-46 (8G*F).........................................................C-18

8-1 Typical Voltages for Given Transformer C-8 AWG and Metric Wire Sizes .........................C-19 Connections ................................................ 8-23 D-1 Metric Conversion Factors............................... D-1

8-2 Recommended Ground Reference Wire D-2 Linear Conversions: English to Metric ........... D-2 Sizes for DC Power Supplies and Bat- D-3 Linear Conversions: Metric to English ........... D-3 tery Facilities .............................................. 8-26 D-4 Temperature Conversion.................................. D-4

9-1 Straps and Wires for the Signal Refer-ence Subsystem ............................................ 9-6 vi

INTRODUCTION

1. PURPOSE. 4. LIST OF RELATED PUBLICATIONS.

This technical manual is a technical reference. It is These publications contain information in support of this designed for military personnel who install grounding, technical manual and are required to accomplish the pre-bonding, and shielding (GBS) systems for communica- scribed maintenance:

tions-electronics (C-E) facilities.

List of Related Publications2. REFERENCES.

A list of related publications appears in Appendix A. The Publication items on this list are not necessarily mentioned in the text. Number Publication Title

00-5-1 AF Technical Order System3. EXPLANATION OF TERMS.

5. IMPROVEMENT REPORTS.A glossary appears at the end of this manual. The defini-tions in this glossary agree with several related publica-

Users of this manual are encouraged to report errors andtions. These are:

omissions and to make recommendations for improving its

• Joint Chiefs of Staff Publication No. 1 (JCS Pub 1) contents. For this purpose, U. S. Air Force personnel

• MIL-STD-188-124A - Grounding, Bonding, and should submit their recommendations on an AFTO Form

Shielding for Common/Long Haul/Tactical Communi- 22, Technical Order System Publication Improvement cation Systems Including Ground Based Communica- Report and Reply in accordance with TO 00-5-1, to 420 tions Electronics Facilities and Equipment SCMS/GULAB, Tinker AFB, OK 73145-3029. U. S. Army

• MIL-HDBK-419 - Grounding, Bonding, and Shielding personnel should use DA Form 2028, Recommended for Electronic Equipment and Facilities Changes to Publications and Blank Forms, and forward it

• National Electric Code (NEC) directly to Commander, U.S. Army Information Systems

• Institute of Electrical and Electronics Engineers (IEEE) Engineering and Interpretation Center, ATTN: ASBI-SST, Dictionary (American National Standards Institute Fort Huachuca, AZ 85613-7300.

(ANSI/IEEE STD 100-1984)

• Federal Standard 1037A, Glossary of Telecommunica-tions Terms (FED-STD-1037A) vii/(viii blank)

SAFETY SUMMARY

etc., which if not strictly observed, could result1. GENERAL SAFETY INSTRUCTIONS.

in injury to, or death of, personnel or long-term health hazards.This safety summary includes general safety precautions and instructions that must be understood and applied during operation and maintenance to ensure personnel safety and CAUTION protection of equipment. Prior to performing any task, the WARNINGs, CAUTIONs, and NOTEs included in that task shall be reviewed and understood. Highlights an essential operating or mainte-nance procedure, practice, condition, statement,

2. WARNINGS, CAUTIONS, AND NOTES. etc., which if not strictly observed, could result in damage to, or destruction of, equipment or WARNINGs and CAUTIONs are used in this manual to loss of mission effectiveness.

highlight operating or maintenance procedures, practices, conditions, or statements considered essential to protection NOTE of personnel (WARNING) or equipment (CAUTION).

WARNINGs and CAUTIONs immediately precede the step Highlights an essential operating or mainte-or procedure to which they apply. WARNINGs and CAU- nance procedure, condition, or statement.

TIONs consist of four parts: a heading (WARNING, CAU- TION, or Icon), a statement of the hazard, minimum 3. HAZARDOUS MATERIAL WARNINGS.

precautions, and possible result if disregarded. NOTEs are used in this manual to highlight operating or maintenance Consult the Material Safety Data Sheets (MSDS) (Occupa-procedures, practices, conditions, or statements that are not tional Safety and Health Administration (OSHA) Form 20 essential to protection of personnel or equipment. NOTEs or equivalent) for specific information on hazards, effects, may precede or follow the step or procedure, depending and protective equipment requirements. If you do not have upon the information to be highlighted. The headings used an MSDS for the material involved, contact your supervi-and their definitions are as follows. sor, or the base Safety or Bioenvironmental Engineering

Offices.

WARNING

Highlights an essential operating or mainte-nance procedure, practice, condition, statement, ix avoid prolonged breathing of vapor or mist,4. SAFETY PRECAUTIONS.

and avoid prolonged or repeated skin con-tact to prevent injury, physical disorder or death.CAUTION

• PERSONAL PROTECTIVE EQUIPMENT

(PPE). To prevent personal injury, adequate• The following are general safety precautions eye protection is to be worn when sprayingthat are not related to any specific procedure connectors with solvent, using compressedand therefore do not appear elsewhere in air, or soldering.this publication. These are precautions that personnel must understand and apply during

• COMPRESSED AIR. Use of compressedthe various phases of equipment operation air can create an environment of propelledand maintenance.

particles. Do not direct air stream toward self or other personnel. Compressed air must• EXERCISE CAUTION AROUND LIVE be reduced to 30 pounds per square inchCIRCUITS. Operations personnel must (psi) or less.observe safety regulations at all times. Do not replace components or make adjust-

• EMERGENCY POWER-DOWN. An emer-ments with power applied. Under certain gency power-down of the entire test stationconditions, dangerous potentials could still may be performed at any time by placingexist after power has been removed.

both the AC power circuit breaker and the 3-phase breaker on the Benchtop Recon-• DO NOT SERVICE ALONE. Under no figurable Automatic Tester (BRAT) to thecircumstances should any persons perform down position. If the RF Bay is also in use,maintenance on the equipment except in the then an emergency power-down may bepresence of someone who is capable of performed by placing its AC power circuitrendering aid.

breaker to the down position. The breakers

• RESUSCITATION. Personnel working with are located on the upper left corner of the or near high voltages shall be familiar with power distribution panel assembly.

modern methods of resuscitation. Such information is contained in T.O. 31-1-141-1 5. ELECTROSTATIC DISCHARGE.

and training sources may be obtained from the Director of the Base Medical Services. Proper handling procedures must be followed to avoid damage to components. Handling instructions for ESDS

• DO NOT WEAR JEWELRY. Remove all items are contained in T.O. 00-25-234. The Electrostatic rings, watches, and exposed pendent jewelry Discharge (ESD) symbol is used to indicate steps or before system power is turned on. Serious processes that require ESD precautions. When the entire injury may result from failure to observe paragraph and all subparagraphs are considered ESD criti-this and other standard safety precautions. cal, the symbol will appear between the paragraph number and title. When only certain steps are ESD critical, they• LIFTING/HANDLING. Improper handling will be identified by the symbol placed between the stepor lifting can result in injury.

number and text.

• CLEANERS, CHEMICALS, PRIMERS,

OR PAINTS. Cleaner and Isopropyl Alco-hol are toxic and skin irritants. When mix-ing and using ensure adequate ventilation, x

CHAPTER 1

GENERAL INFORMATION

1.1.3 This publication deals mainly with fixed facilities;1.1 GENERAL.

however, the concepts covered also apply to mobile facilities.1.1.1 This publication covers practical aspects (rather than theory and design) of GBS systems. For theory and design,

1.1.4 Existing facilities need not be retrofitted for the solerefer to MIL-HDBK-419 (Grounding, Bonding, and Shield-purpose of complying with this publication.ing of Electronic Equipments and Facilities). The standard basic requirements and goals for grounding, bonding, and 1.1.5 Some of the topics in this publication are:

shielding for new as well as existing military ground C-E facilities are contained in MIL-STD-188-124(A). • (1) Personal safety and first aid.

• (2) Lightning protection.

1.1.2 The emphasis in this publication is on installation, • (3) Electromagnetic pulse (EMP) from nuclear weap-as opposed to operation and maintenance (O&M). For ons.

Army personnel, O&M of GBS systems are covered in FM • (4) Electromagnetic interference (EMI) and electro- 11-490-9, Communications Facilities: Grounding, Bonding, magnetic compatibility (EMC).

and Shielding.

1-1/(1-2 blank)

CHAPTER 2

SAFETY AND FIRST AID

2.1.7 When working with high-voltage capacitors, use a2.1 SAFETY.

shorting bar or wire across the terminals. A shorting probe (Figure 2-2) will be used to ground all dangerous circuits2.1.1 In addition to the following safety practices, all and capacitors.personnel must be familiar with the safety practices listed in TO 31-10-3, Outside Plant Installation.

WARNING2.1.2 Conspicuously post warning signs in any place where there is danger that people could accidentally come into contact with exposed sources of high voltage. This When working on or near electrical equipment, danger is particularly high around power lines, antennas, do not wear metal items such as wristwatches, power supplies, or any place where uninsulated contacts rings, bracelets, medallions, or identification can be touched. Signs used will be precisely worded and tags. Such items are excellent conductors. If illustrated so there is no mistaking the danger. Signs will they come into contact with “hot” conductors in also warn of related dangers such as radiation, acid, and the equipment, the wearer is likely to receive an noxious fumes. Anything that can pose a safety hazard will electric shock.

be pointed out.

2.1.8 Follow these precautions when working on ground

2.1.3 Some items of equipment contain built-in power systems or power distribution systems:

cutoff features. Operate this equipment strictly according to its intended use. Do not use it in any way that might a. Always treat ground electrodes as if voltage exists prevent the power cutoff from working properly. between test leads and any other point on the station ground network. Never let the hands or other parts of the body complete a circuit between points that could have different voltage potentials.

b. Work inside opened live power panels or on equip-ment with potentials above 60 volts (V) only if qualified to do so.

c. Work with at least one other person whenever “hands-on” inspection or repair is required.

d. Wear electrician’s rubber gloves when working onFigure 2-1. Ground Warning Tag live electrical equipment 600 volts or above. Make sure the gloves are in good condition. Where there are rough edges, sharp points, metal filings, or2.1.4 A Ground Warning Tag (NSN 9905-01-008-0819, other such conditions, wear leather gloves over themanufacturer part number GMP 01068 or suitable substi-rubber gloves.tute), (Figure 2-1) will be attached to all ground wires as close to termination point as possible, but not further than

e. For electrical work, use only approved insulated12 inches from connections and/or termination points.

tools in good working condition. Do not use tools with handles covered with friction tape or rubber2.1.5 Special dangers exist during installation of certain tape.equipment. Use warning tags to point out dangers when individual circuits or stages are being checked. These tags

f. Wear safety glasses when working on live powerwill contain appropriate information to alert all personnel panels and equipment.of the dangers involved; they will also note any specific restrictions on using the equipment. g. Before opening a ground lead, bypass it with a safety bonding strap (Figure 2-2). Otherwise, volt-2.1.6 When working with high-voltage devices, ensure age at the disconnect point could cause an electricthat the devices are grounded and that the high-voltage shock. Before attaching the strap to the groundcircuits are disconnected or turned off. Do not rely solely system, check to see that the points where it will beon the presence of interlock switches for protection from attached are clean. Typical points of attachment areelectric shock.

a permanent ground wire and the protruding part

2-1

(the part sticking up above the soil) of a ground i. Do not make inspections or repairs while lightning rod. After the strap is in place, the permanent storms are nearby.

ground connection can be opened.

j. Except for test equipment, do not use metal rulers

h. Do not disconnect the safety strap before recon- or other metal objects near electric circuits.

necting the permanent ground. Reassemble the permanent hardware, secure it, and apply an anticorrosion treatment. The safety bonding strap may now be removed.

Figure 2-2. Shorting Probe

2.2 FIRST AID.

Table 2-1. Probable Effects of Electric Shock

2.2.1 Electric shock can cause heart spasms (ventricular

fibrillation) or paralysis of the respiratory center, either of Current in Milliamperes (mA) Effects which can be fatal. While electric shock is never without

Alternat-danger, certain combinations of voltage and frequency are ing Cur- Direct Currentparticularly harmful. For example, voltages between 200 rent (ac) (dc)and 1000 volts at commercial power line frequencies can

0-1 0-4 perceptioncause both heart spasms and paralysis of the respiratory center. Lower voltages can also kill. It is not the voltage 1-4 4-15 surprise itself which kills, but the resultant current. The voltage 4-21 15-80 reflex action necessary to produce a deadly current depends on the

21-40 80-160 muscular inhibi-resistance of the body, contact conditions, and the path tionthrough the body. Table 2-1 lists the effects of electric

40-100 160-300 respiratoryshock. Sufficient current passing through any part of the blockbody will cause severe burns and hemorrhages. If the current path includes a vital part, such as the heart or lungs, Over 100 Over 300 usually fatal even relatively small currents can kill.

2-2 requires use of the back-pressure-arm-lift method. Person-nel who regularly work on or near electrical equipment will be trained in both methods.

a. Mouth-to-mouth method.

(1) Remove foreign matter from the victim’s mouth.

(2) Tilt the victim’s head back so the chin points up.

Pull or push the jaw so it juts out (A through C of Figure 2-3). Clear the airway by moving the base of the tongue away from the back of the throat.

(3) Open your mouth wide and place it tightly over the victim’s mouth. At the same time, pinch the victim’s nostrils shut (D of Figure 2-3). Blow into the victim’s mouth.

(4) If you feel resistance to your blowing effort, and the victim’s chest does not rise, recheck the head and jaw positions. Blow into the victim’s mouth again. Sweep your finger through the victim’s mouth to remove any foreign matter.

Reposition the head and jaw and blow into the victim’s mouth again.

(5) Remove your mouth, turn your head to the side, and listen. If you do not hear the victim’sFigure 2-3. Temporary Safety Bonding Strap breath, attempt to clear the airway again ((4) above). If you do hear a return rush of air, blow into the victim’s mouth again. For an adult,2.2.2 Before touching a shock victim, disconnect the blow vigorously 12 times per minute. For acircuit or move the victim away from the live conductor.

child, take shallower breaths and blow 20 timesTo move the victim, use any suitable nonconductive object, per minute. The smaller or younger the child,such as a dry wooden pole, a belt, clothes, or a rope looped the more shallow your breathing should be.around the victim.