MIL-STD-188-124B.pdf

MILITARY STANDARD

GROUNDING, BONDING AND SHIELDING

for Common Long Haul/Tactical Communication Systems including Ground Based Communications- Electronics Facilities and Equipments

MIL-STD-IB8-124B

1 Feb 92

SUPERSEDING

MIL-S?-D-188-124A

2 FEBRUARY 1984

“L-” AMSC NtA

AREA SLHCITCTSIEMCS

DISTRIBWION STATEMENT A. Approved for public rdease; distributi~ is unlimited.

MIIXTD-188-124B

FOREWORD

“1. ~W~&tiiu~mvddA~tir=byW~*d_ oftk Dqwtmmt of Defense in wmrdance with Dqartmat of Defense Ir@uction 5000.2, dated 23 February 1991.

2. Beneficial comments (rwco~ “wls, additions, deletions) Und any peztiwnt dllta which may be of use in @XOViIl$j this document should be wkksed to: TIC/’I’IS, Scott AFB IL 622254343, by wing the self—addmukd StandardbWion DocumeQt Improvermmt I%posal (DD Form 1426) qpwing atthelmd of this docummt or by letter.

3. Stmduckf mahlilitar’yco mmunications am published m part of a MIL-STD-188 mri= of documam:

Miiitary Cmmmidl ‘cm System Technical Standurk are subdivided into C4xnmm XMg HauUTacticd Standar& (MIL-STD-188-1OO eoria), Tactical Stmdarcb @fILS’D-188-2@ aaries) and Loag Haul Man&r& (MIL-STD-188-300 ties).

4. ‘rhisdocumm tcxmtain stechn.icalstdards mddesigno bjectivest omsurct heoptimumpd~

-d- telecoxnmuni of cations C-E equiprncmt imkahtions. This is accmnplishod by reducing noise and by providing xkxpk prddkm against power system faults and lightning strikes. Thorough amsideration must be given to the grounding of equipment and facility itudbtions, the bonding required, and the methods of shielding mkd impkxnentat.ion needed for ~1 * ad equi~t cxmtrd.

5. l%isstandard isalsorecomrncwkd for applicable use on my ground IkiMY or cquipm=t M- ~un~g, bonding, shiekiing, personnel m&/y, i.ightning snd EMC - required. Exampk of such f=ilities are aircrafi Sirnukom, cOmputer miters, kboratory buildings, weapons checkout and *ly, etc.

6. Paragraph 5.1, C3rounding, for this standard is divided as follows:

L Detailed reqtliremm ts for facilitk, including buildings and associated stmctures used principally for C-E equipment.

IL Detailed requirements for C-E equipxmnt w#kh address grounding, bonding, and shielding for tactidlong haul fixed ground tnwprtibks and military communications ektronics cquipmcat iIMdhtiOIIS and associated subqmtems.

7. Detailed requircments for Bonding and Shielding are contained in 5.2 and 5.3.

8. This sbmdard is tier implemented by MIL-HDBK-419; Grwn&ng, Bonding, and Shielding fbr Electronic Facilities and ~pIIX!@L

9. Notatkmsarwnotwuxiin th.isre visicmtoidcz@_~ withrqcRA totheprevious issucducto@M extcnsivaless of the changes.

ii

MXL-STD-188-124B

CONTENTS

1.

1.1 1.2 1.3 1.4 1.5

2.

2.1 2.1.1 2.1.2 2.2 2.3 2.4

3.

4.

4.1 4.2 4.2.1 4.2.2 4.2.3 4.3 4.4

5.

5.1 5.1.1 5.1.1.1 5.1.1.1.1 5.1.1.1.2 5.1.1.1.3.

5.1.1 .1.3.1

5.1.1 .1.3.2 5.1.1.1.4 5.1.1.1.5 5.1.1.1.6 5.1.1.1.7 5.1.1.2 5.1.1.2.1 5.1.1.2.2 5.1.1.2.3 5.1.1.2.4

SCOPE . . . . . . . . . . . . . . . . . . ...+....”””0=”oOOOCOOCO. .***”*

-* *~ ** .” ’* ”” ”” ’’”” ””””w”” “-’””””””b”’’””””””’-”” -t....*.*...*...*.*** ● ******”””=””**””””*”””*’ ● “” ~li~om . . . . .. a . . . . . . . . . . .6...0000”O”S”OOO00””*0000 ●

Obj=tiv= . .. t . . . . . . . . . . ...*.”~~c~”o”o”-.o””” ““””””””””’ System S~mdHpObjAv=

REFERENCED D-ENTS

Governmm tDocummt8 . . . . . . . . ...*.... ● ***=****”””””””’”””” Spocificatiom, StaxKkk and Hmdbocb . . . . . . . . .****...* ● ******** Other Govcrnmm Doulmen ts, Drawing8, aQdPublicatiml. ● *****..******* OtherPubi.ications ...*......*.. ● ************””*””””””*”* ““” Source of Docummts ..*....**...**=** ● ** ** ”” ’” ”””* ”* S”””””” ofderofPmAcnce . . . ...*.*.. ● *.**********”””**”””’””” ““”

DEFINITIONS . . . . . . . . . . . . . .....~””.”e””””””-””””- “~~q””””

GENERALREQUIREMENTS

General . . . . . . . . . . . . . . . . . . . - . . . . . + ” ” ” ..”=+..”” +-+”.?””” Grounding . . . .. * . . . . . . . . . . . ...00 ..+.00w*=~””o-o.=”0~0= ●

(3eacral . . . . . . . . ...*... ● . * . * * * . * * - * ”*””””.-” “’””””...”” Tacticad Equipmen@md Fwtiti= Grounding inAmticRegim Bonding . . . . . . . . . . . . . . . . . . ● ** ** .* *$ * * * * G* .”..””.”. ““”..

shielding . . . . . . . . . . . . . . . . . ● ** . .. O*”*””””””*”””*”* .“””””

DETAILED REQ~MENTS

Growding . . . . . . . . . . . . . . . . . . . . . . . . . ● .O. *00 ”.. SGQOOOOOO.

BuikiingandStmature. . . . . . . .........~..t.”””””..~ ● .0” .0*.* Eutb El@rodeSub~tim General . . . . . . . . . . . . . . . . . .....+....o”o=”D”.D...s •w~o””” Earth Rcsistivity Swey . . . ..G6 . . . . . . .. e.. .”eg$. .”eg$ .$<””””.

Minimum configuration . . . . . * . ...*..*. ● *..*******...””””.”** Resistance toEaA . . . . . . . . . . . .....=O*DJ”S”OOOO=OOOO”” ● *00” AdditioMI Ccmsidcfaticm . ...*.* ● ************”””””.””””. ● “””” GroundRods . . . . . . . . . . . . . . . . .........’.=”,”.~””””.””” ● *O Cunnedng Rimes . . . . . . . . . . . . . . . . . . ...=...=”””” .“””””.””=.

0tkUndqpundMc4als wwtance Ckks . . . . . . . ...*.* ● *****.*$*.****+*.*”.””.” ““” FaultPmtcction Subsystem . . . . . . . . . . . . . . . . . ..s. .~..””~ ...=”..

Gtawal . . . . . . . . . . . . . . . . . . . . ● *********””.”””*”*’.’””*” “ Building Stn@ural Ski Pipes aod Tubes . . . . . . . . . . . . . ......a”..”~”””””s.~’”” •~*00” ElectricalSupporting Stmctwes . . .. ****~**********”* +“...”.”””.

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5. I. I.2.5.7

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5. LL3.3

5. LL3*4

5. LL3*5

5. LL3.6

5. LL3.7

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5. J. L3.8J

5. I.s.3.8.2

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iv

MIL-STIH88-124B

u

CONTENTS (con’t)

‘bL..-

I!mm!d2 5.1.2.1.1.2

5.1.2 .1.1.3

5.1.2 .1.1.4 5.1.2.2 5.1.2.2.1 5.1.2.2.2 5.1.2.2.3 5.1.2.2.4 5.1.2.2.5 5.1.2.2.6 5.2 5.2.1 5.2.2 5.2.3 5.2.3.1 5.2.3.2 5.2.3.3 5.2.3.3.1 5.2.4 5.2.5 5.2.5.1 5.2.5.2 5.2.5.3 5.2.5.4 5.2.6 5.2.6.1 5.2.6.2 5.2.6.3 5.2.6.4 5.2.6.4.1 5.2.6.4.2 5.2.6.5 5.2.6.6 5.2.7 5.2.8 5.2.8.1 5.2.8.2 5.2.8.3 5.2.8.4 5.2.8.4.1 5.2.8,4.2 5.2.8.5 5.2.9 5.2.9.1

Equipment Si@G-d T~w Shield Terrnina tionsof Coaxkland Other Highti Fq_cy Cabk Overall Shields m.. o. O. O..... . . . .. ”. O” O”” BD=OOOOOOOQ““””=”” FaultProte@ion Subsy*m G- . . . . . . . . . . . . . . . . . . . ....00s0ooooQo=D”oso”Q.”0 “~+ Pemonnclprotection . . . . . . . . . . . . . . .. 0. .0 .$9. 0” O”O”O”Q “o-o”” ACPowerNe@d . . . . . . . . . ..”= ”~””ooo”wo ● “OO” O” O” CCOS”OOW IndividualPowarIineFilters convcOicweoutl* . .*.*.****.******”””””” ● “””””””””’’”””” PortableEqtipmt Bonding . . . . . * . . . . . . . . . . . . . ● *****.”**”””*””*”””””””” ““” General . . . . . . . . . . . . . . . . . . ● .* *4 *” ” *$””””*””’”””*”” ““”.”

Surfkce PlatigsorT-t~@ BondProt.ection . . . . . . . . . . . . . .. +. .. OOOO” O””O*”O ‘o...”...”.

Corrosion Protection . . . . . . . . . .. Oc. c*. Ob*OODo. O● bee...””..=”” Compression BOndSinPIO@h Vibration . . . . . . . . . . . . . . . .=...OOCOO*OO*O+C”CO.O ● ...***”*

Bmdirlgstraps . * . . * . . ...**..* ● * . * * . . * * * . ” . ” * ” . ...”...” ““” Bond R-itice . . . . . . . . . . . --..+........”.””””” ““0~.0+.0”0 Material . . . . . . . . . . . . . . . . . ..~OOO”O=”OOOO*”OOO””O.” •00~* Sweat Solder . . . . . . . . . . . . . . ....~.....~”~.”..”~.’” “+”..””” Brazing Solder . . . . . . . . . . . . . . . . . . . . . . . . . . ...”..-. ● -o....”.

clamps . . . . . . . * . * . . . . ...**...* . . . . . . ” ” . . . . . ” . ...”..”. .

Nuts, Bolts andWAem Direct Bonds . . . . . . . . . . . . . . . ......c’.~-..””.”..o.... .“.”” welding . . . . . . . . . . . . . . . . . . . . . . . . ...9*....””.”..”*” .“””.

Brazing and SihmrSoltig. . . . . . . . . . . . + . . . * ” ””*”...”. ..-”...

Bondingofqqlerto steel tifiwldtig .ti . . .. . .. . . . . . . ........+..*=””~o”o.”.00 .“””” swcatsoldcring . . . . . . . . . . . . . ● ****.**”**”””””’””.””.. ....- Sheet Me$alorDuctWork . . . . . . . .............=*””.”0$00. “~”~+ Baiting . . . . . . . . . . ..*.....* ● **.*****”**””*”*..””*. ..”””.

Cuampsand springq Indir@Bonds . . * . . . ...**.*. ● ** ** .* .* **** *””” ”.”s”* .“”””” surfacaPmpamtion . . . . ..*.o. ** ** ** ** **** *’*” ””’.”g .“ .””.”” AI’catobe cleaned . . . . . . . .. ● ** ** .* ** ***” ~*”*””””. “.”””..”” l?aintkmovd. . . . . . . . . . . . . . ● ****.***”**’”””’”.””””” “.””” Inorganic Film Removal . . . . . . . .........~..”~.=”...”e *“””””D.

Final Cleaning . . . . . . . . . . . . . . ......~..”o~oG.oe~Q~*.o” ■ “”=.

Clad MetalS Aluminum Alloy . . . . . . . . . . . . ● . * * * * . * . ” ” * ” ” ”.**..... ““”*””” @npletionoftheBond . . . . . . . . . . ........~

DummlarMetals . . . . . . . . . . . . . . . . . . . . . . . . . . . ...””.. .~” COrrcwion Prev@ion. . . . . . . .. 9 . . . . ..060 CCC..060C . .. O++..+.”

v t

MXL-STD-188-1Z413

Comm (con’t)

JkME@!

5.2.10 5.2.10.1 5.2.10.2 5.2.11 5.2.12 5.2.13 5.3 5.3.1 5.3.1.1 5.3.1.2 5.3.2 5.3.2.1 5.3.2.2 5.3.2.3 5.3.2.4 5.3.2.5 5.3.2.6

Encloauo Ikmding ..*?....**.**. ●..*. .*. .*. ..** . . . . ..*. **.27 Sul.mounw “Os . . . . . . . . . . . . . . . . . ● ..*.***..*.*.*..*.* ●****” B @p-b . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...+ Connector Mounting ShieldTcl” t ions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .....~ RF Gulkets . . . ...*.....*.*** ● *************.***-****.* ●**28 sbiekiing . . . . . . . . . . . . . ...**- ● ** ** *. ** ** ** **** **** ”***o ● 29 Gcmral . . . . . . . . . . . . . . . . . . . ● ************************ ●**29 Basic shieMingRequircments... .*. . *=********.************* ●**B shielded w cmlrea . . . . . . . . . . . . ● ..**=*******-*.* .**, *.****Q 29

EkctromagneticI nterfumce@MI) tin~l . . . . . . . . . . . . . ..*.. . ..*.. ● **..* ● **.*. ..***. ..*. 29

Gaskets Filter Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...+.. .......c29 OXltrol ofApertur= ..*...... . . . . . * . . * . . . . . .*.***... . . . . ..*3Q wireand mkRouting . . . . . . . . . . . . . . . . . . * * . ...*.* Telephcme Cable Shields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..=30

APPENDIX -Dku=ionofSigxd ~sY*IIIs........... -..o.-*..O+G:G00...’OO 32 ‘4

FIGURES

ri4im2

ExampleofEquipotcnti.al orMultipoi@Grounding to Earth Electrode Subsystemfor OverheadPhme

Example ofEquipotential Pianeto EarthEk@rodc subsyzltern (Nwconstmction) . . . . . . . . * . . * * .*.*...*. . . . . . ..”””11

Typicnl Single PointEntry forExtorior PenctAorm(TopVi~) . . . . . . . . I TypiudEnt.ryPlat.e ShowingRigidCable, Conduit aIld PipcPcnetmtions . . . . . . . . . ● *.*** RadiusandAngkofDownCunductOrH .

TypicalEquipotcAal GroundPlaneforHigher

FrqueaKyIrdlation(lkxvConStrUCti) . .

. ...0.. . . . . . . . . ...*.* ..* 13

. . . . . . .*..*. ● **... ● ***** 17

MIIATD-188424B

1. SCOPE

u

1.1 J%fpOse. ‘hisstmdardtihk the rninirnumbc rcqummmts and goals for grounding, bomhng, and shielding of ground-breed telecommunications C-E equipment indkt.ions, subsystems, and facfibes mchding buildings and StlUCt’LLf= mqqmrting tacticai and long bad mihtary communication systems.

1.2 QQrltent. This standard addrea= the tkcilities gtuund system, M well as pounding, bonding, d shielding and lightning protection for tekmnrmmications C-E Ikcilities and equipments. Grounding for building and structures is ikted under the headings of Earth Electrode Subsystem, Fault Protection Subsystem, Lightning Protection Subsystem and Signal Reference Subsystem.

1.3 &mlieatl “ens. This standard shall be used in the design and engineering of new ground-based military communication systems, subsystems, and equipment imtdations M well as those C-E ficil.ities undergoing major retrofit. This includes air traffic control and navigational aid facilities, radio, radar, satellite ground tmninals, telephone central offices, microwave and data eornmunications systems, as well as C-E transpotiks, airerafi simulators, computer centers, and wtqon assembly facilities. When upgrading existing t%ciliti~ for installation of minor C-E equiprneats, the mquiremmts of this standard shall be estabhshed on a case-bye basis by the cognizant agineering agency. Use of this standard for other ground C-E f~ilities a equipment is also encouraged. It is not to be used solely as the basis for retrofit of existing C-E facilities. It 4WXnot apply to general construction such as bamacks, administration buildings, dining facihties, wmkusca, and non-communiwtiom fiiciliti=, nor does it apply to mobile units such as tanks, trucks, jeeps, ck.

1.4 Objectives. The objectives of this standard are to provide for the protedion of personnel, equipments, buikiings and structures against the hamrds posed by electrical power faults and lightning stri.kea. R also provides for the reduction of noise ~d electroma~c interference caused by imdeqw@ ~tig, wm and shielding of ground baaed military communications installations to aweptable perforrnarw levels. It shall be required that the grounding, bonding, and shielding system be eagineemd to be eornpat.ib]e with the suppkmmta,l requirements of the specific equipment or fiuility supporting these communications.

1.5 Svstem Stanckis and Desire 0 biectivcs. The pammeters and other requirements specified in this document are mandatory system standards if the word ‘shall” is used in connection with the pmameter value or requirement under consideration. Non-mandatory design objectives are indicated by parenthxes after a stamkbd parameter vahe or by the word ‘shodd * in eomection with tbe panmekr vahe or requirement under eonsikation. Fx ,a dehition of the terPS( ~system stankd” and “design objective” (’DO), see

FED-STD-1037. .

2.

2.1

MIIATD-188-124B

REFERENCED DOCUMENTS

2.1.1 fkmcifications. Star@@s. ~ unless Othmvise apccifiod, b following qmcificstions, stanc&&, iriWi&.MWiu3df W issue likted in that issue of the Depwtmmt of ~fcase Index of Spccifi@ions and Skamkis (IX)DISS) specified in a solicitation form a part of this standad ‘b the ekmt specified herein.

SPECIFICATIONS

FEDERAL

P-D4J0

TI’”P-1757

STANDARDS

FEDERAL

PED-STD-1037

FIPs PUB 94

MILITARY

AN-735

AN-742

MKL-E4051D

MIHTD-285

MIIATD454

MIL-ST’D461

MIL-STD462

MIL-STD463

MIL-STD-1857

Dr’Y-d J%P’-’@wti

Primer bating, Zinc Chmxm&, Low Moisture Scasitivity

Glossary of Tekmnmunication Terms

(h&Mine on Ektricd Power clamp, Loop Type Bonding

Chuup, Loop, Plain, support, fi)r ADPxMtaMhM

AirCmfl

Ehxtm-c Compatibility system Requhmmts

At&amaticmMeasummat for Enclosures, Electromagnetic Shiekiing, for EMronic Test Pu.rpms, Method of

Standard Geswral Requiremca ts for Electronic Equipment

Ektro_c Emiaskm and Susce@ibility Re@remm U fix the Control of Ekmm8gnetic Irlterf6rcan

Eiectmmagna “cIntcrferaMx C&mc@ma“ “u, Mcasummm t of

IMnitions and Systems of Units, Ektmmagnctic I.nterfercme and Ei~_C Compatibility Tec&oiogy

Grounding, Bonding md Shielding Design Practices

MIL-STD-188-124B

MIL-C-83413

MIL-sTD-188-n5

HANDBOOKS

MILITARY

MIL-HDBK-232

MIL-HDBK-419

MIL-HDBK-1 195

FM-1 1-487-4/

TO 31-1024

Connectors and Asscrnbli=, 13ktrical ~ Grounding: Type IV Jumper Cab~e Assembly, bad, E~

High Aititurio Ekctmnmgnetic Pulse (HEMP) Protection for Ground-Based C41 Facilities

Rcd/Bkk Engkerirlg IrJdktion Guiddina

Chunding, Boding, and Shielding for Ekctronic @ipIllUltS amd Faciiitia

Radio Fmquemcy Shiekkd Enclosures

II18tauation Practices: COmmui@km systems Groundm“ g, Bonding, and Shielding

2.1.2 Other Gove-~ hwJQ . -d

s Publications. Tbe following other Govemrrmt docummts, - drdwi.ngs, and publications form a put of this starxkd to the exht qccifled herein.

DOD Directive 1000.3 - Safety and Ouqational Health Policy for the Dqutrnent of Defeasc b DOD -W 3222.3 - ~t of Def~ Ekctromagnetic Compatibility PrOgMM

(Copies of specifications, standds, handbooks, drmvings, and publications roquircd by contractors in cormedon with lkpecific acquisition fimctions should be obtaird from the contracting activity or as directed by the eontrwXing officer.)

2.2 gtber Publications. ‘IIM following doa.uncn t(s) form a part of this standard to the exteat specified hereim l%eissuesofthc documents which areindicatdas DOD adoptod ahallbe thekuelisted in the current DODISS and the supp)exrmt thereto, if applicable.

AMERICAN INSTITUTE OF STEEL CONSTRUCTION (AISC)

AIsc S326 Specification for the Design, Fabrication and Erection of Str@ural Steel fix Buildings

(Appti4m for copi= of the AISC specification should be adchad to the brican Institute of Steel ConstnAon, 400 North Michigan Avesme, Chicago IL 60611.)

AMERICAN SOCIETY FOR TESTING AND MATERIALS (Am

ASTMB32 - Standard Specification for SOMer Metal (DOD Adopted)

(Application for the ASTM document should be addmsmd tothe/wrkaIISo cietyfbrT=ting@M-, 1916 Ram Street, Philadelphia, PA 19103.)

MIL-STD-188-12413

AMERICAN WELDING SOCIETY (AWS)

.4. .,. . >.! . ,.

AWS A 5.8 Spccifiaitim for Brwing Filler Metal (DOD Adopted, ANSI Apf.woved)

(Application fix the AWS specification should be addmmcd to the Armxkan Welding Society, 550 Nmthwest hjcunc Road, P.O. Box 3510$0, Miami, Florida 33135.)

NATIONAL FIRE PROTIXXION ASSOCIATION (NFPA)

NFPA No. 70 - National Eicctrical Code

NFPA No. 78 - Lightning Protection code (ANsl AppNYved)

(Appli@ion for NFPA-70 or 78 should be addmsmd to the National Fire Protcdon Aaso&tion, Batterymamh Park, Quincy MA 02269.)

(Industry association specifications and standards are gtmerdly ●vailable for reference from libraries. They are also distributed among technical groups and using Federal agmcics.)

2.3 _ of ~ Co@@ of Federal and military atandmk, apecificatkns, and amocktd docqmts,, listed in tbe De@mcnt of Defrmsc Index of Spccificationa and Standad (DODISS), ahouid be obtaind from the S~ “on Ordm De&, Bldg 4D, 7(K)Robbins Avcmw, Phikk@da PA 19111-5094. To expedite a customar’s ability toobtainadocumant, ●coqu@iA Tekpkme ~ ktry Sy6tem ~=) bas b impkmontadwhichpfovidll%thle cqlaldity toplace mmrderd irtctlyi ntotbem mpu!orviaatouckmc v’ telephone. This system may also be used to receive immediate * or follow-upon a previously submitted order. Inorder touae TOESyou muat obtain your cuakmer number fiompmvkualy ordered material. Ifa cwtonmr zmmber has not bdm aaa@ned, ~ ~ be obt&md by ding AC (21S) 697-2179 or DSN 442-2179.

TOES can then be aaxmaed by dialing AC (215) 679-1187 or DSN 442-1187. It is imptamt m replam the letter ‘Q” with the number ‘7” and tbe ktter “Z= with the number “9- since the telephone dial does not include thwe ktturs.

Copies of industry association docurrmts should be obtained fiosn the sponsor. Chpk of all other listed douimmts should be obtained km the contracting activity or as directed by the contracting officer.

2.4 @k of ~ Intheevent ofaconflict between thetextofthis atmdard andtherefereaces cited hamin, thkxtofthis6 t&dardl dWakepmcdmcc.

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MUATD-188-124B

3. DEFINITIONS

For military communications dctiitions, see FED-STD-1037. Terms related to EMC dtxunmts an be found in MIL-STD-463. The following am definitions of ac”ronymsused in the stdard.

ADP

AWG

C-E

Do

EMC

EMI

FIN

GFC1

HEMP

N_FPA

TOES

. Automatic Data Processing

&wwkan Wire Gauge

Communications-Electmmics

Design Objective

Electromagnetic _bility

Electromagnetic Interference

Federal information Processing standard

Ground Fault Circuit Intemptcr

High-Altitude Ekctromagnetic Pulse

National Electrical Code

National Fim Protection Association

Telephone order Entry System

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MIMTD-188-124B

4. GENEML REQUIREMENTS

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4.1 _ ‘I’heneed exists for #@4ive grouding, bonding, md aiklding of (1) okctricalkktfonic Oqtipm@ltSand (2) buikiings =d ~ (facilities) in order to achieve improved equipmmt opomtkg efficieacka and increased safety practirn. ‘l%ese ~~ -1** *~ of ~=~-~c inter-fercnce (EMT) and noise by the proper gmmding, bonding, and shielding of C-E hcilities and equiprnmts.

Tllisrequirenmt alsoisintecdedt optectperaomd from hazdoua Vdtafp due to electrical power faults, lightning strikes, and high level electromagnetic radiations amocktd with normal equ.ipmant operation and

.ma@mamX htiw~-sy-tia-~ofklw~~adti

Varioul$power and communication equipm(alts. This effectively minidm% voltage differdak on the ground plane which exmed a value that wiiI produce noise or intdemnce to oomrnum“cation circuits. Peraoone land equipment protection is afforded when, during an wxwrmce of8mkctricaigNnmdfbuk@legmlnd system provides a path for rapid operation of protective ovemurremt devices; or, during ● lightning strike, pruvides a low impedance path for currmt to earth. Personnel and equipment protection against power huh currents, static tige~d~d h@~tivw tih~ti&~by ptive_~dby_d normally non—currlmtCurying metal Objects, including stmctud @eel lmppolt rm!mlbers, to the fklcility ground system. This ground system alao provides low iqedarm paths ktwoen various buildings and @mctures of the filcility, as well as betweerl equipments within the fkcility, to* in order to minimim the effects of noise curreats. For additional information refer to the supporting doaunmt MIL-EIDBK-419.

4.2 Groun&nR.

4.2.1 General. The facility ground system consists of the folJowing ekxtrically interconnected subsystems:

a. ‘b earth ekctmde subsyttcm, including the various interwmected Lmtaliic elements such as buried fuel tanks, towex bases, fences, water pipes, etc.

b. The fiudt protection subsystem.

c. The lightning protection zmbsystem.

d. The rngnal refereuxe subsystem.

These items, in their entirety, compose the total ground system for the facility (See 5.1 and the Appndix).

4.2.2 ~acticd ~men ta and Facilities. The grounding, bcmding, and &ieJding mqukemmts for tactical equipments and facilities am similar in cxmcept to those for fixed C-E ficilitiea. For specific a.ppii@ions, see MIL-HDBK419 and FM 11=4874T0 31-10-24.

4.2.3 Qroun~tic R- See MIL-HDBK-419 for hforn@I ‘on on ground pmcedums for arctic conditions.

4.3 - AWtimdmtid tim~Mdc~*b@&alm-Mm path b@weentkn. Bonding istheprocdum bywhich tbecmductive aurfke ofa mbamembly or Compomxlt is electrically cosmocted to another. ‘Ihia prmmta &velopmmt of electrical potcahls beWetm individual metal mrfaces for all fmqucacim capable of cawing intier@we. (See 5.2).

‘w MIIXI’D-188-123B

4.4 ~ shidd.ingh-rn~d~~ to prevent the equipment km pqngati.ngin ti===dbxb+p-h~c - ofin~ PWwb-cktrical and cktronic devices. (See 5.3). For indiviti equip-t shid~ mquhmalts, ~. ~

MIL-STD-461 d MIL-STD-1857. Test procdr= am provided in MbSTD462. If it is dc$uzmd additicmal fielding in the form of ● shid~ eacl~ (m= room) is required, B MIL-STD-285 and MIL-HDBKs419 snd 1195. Faciliti- rcqtig HEMP shieltig should rcibr to KIL-STD-18V1M.

I1

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MIL-STIM88-124B

5. DETAILED REQUIREMENTS

5.1 GmLq@&& mekilitygrwlmd ly$tane0m8ias of f0ur~ Y~$@V=J=-== c“ Li@ningprotection subsystem.

d. Signal ref~ mbuystem.

TiM?SCsubsystems compose the Facility (%’ound SyStOmad arc Admsaed indc$ail inthcfoiknving sections.

5.1.1 -and Stwturq

5.1.1.1 ~ E@mde SUIWVQWL.

5.1.1.1.1 ~eml. hcartheketmde subsystem aballbcmstalledby themsponsible fiwiMicseq@=@ activities at emch C-E hciiity to provide 8 10W~pathtocarth for Lightuingand powcrfault curreatsand c!mlumtbtbazdous Voltagc!doxmtoccufw itillnthefacility. “f’bdwystem llballb ccqableofdkipating to +tia~of-m -kwtiti~egdm~itif. Tb.issystcm shall also inbmmmct all driwzl cketmdcl! and undqmmd nmtalobjccts of the C-E ficiMy. ‘J%eedhoktrodc albf3ystom ahldlnotdegmde tiqunlit'y ofllig@rntid@tim wmected toit. l%r more details regarding iustaUion pmctim, K MIL-HDBK419.

5.1.1.1.2 ~ev<

‘nJe design agency shall duct an earth msistivity sum’ey at fixed permawmt aite!sbafom fbci.iitydc%ign. survey datashall in!chldcalldat8an din fornAonneedcd fofficil.ity

~b. m8ul%wyshallinc~* memmmmt ofeuthn?8i8tivitic@ andmcxmding of fbatumumlcllas typcofsoil, ton’ain,rainfd lmarea~,m-- ~-g- -istiWy,andsi. mik significant factom.

5.1.1.1.3 ~a?ll mx’afi tim ‘Ildasiceu’ thektmciemb6ys@mamfigumtiQf3ahall Oonsistofdrivezl _ rods uniftiy qmced around the facility and placed 0.6m (2 &t) to 1.8m (6 feet) outshkthe dcip hue ted with a 1/0 AWG (American Wire Gage) bare copper cableOfst.ructures. ’I’’hemd sshallbeintelwmn= buried at ]cast .45m (1.5 feet) below grade level. hrger size cdles as well as gm#er bud depths shall be q=ifiui wbrc earth and atmoqkm considerations so dictate. TIE in~ goablebllbeblamdor woidedtoeach ground mdandticl~mitifti forma compkt.ebopwiththecdsti orweldad -. (% Fi~ 1 and 2). Where ground welb are employed, aaqtable COmptwsion typ ~to~ may bcutilimd to bondtheoable totbe grotmdrod. Cov~eof&ti4_ ~by~t, concrete, etc. sllmllbc dim%mgdmldkqttoa minimum inanefiort to maintam“ the efkti~ of the mlbsyatem. R&r to MIL-HDBK419 for additiotld in.formxtion.

5.1.1.1.3.1 ~to Eul’th. @3)mtimbdoftih~-mtiddw exceed 10 Oh.m at tixed prmanent fkilities. Rarhtame to amh for tacticai and transportable systems &odd Dotcxcc@d the Doestabliuhodfmtbo putblarl!lystom.

MIIAH’D-188-124B

5.1.1 .1.3.2 /@@ma! wdemtiom. Whefclo ohmsare notobtaind at fixdpermanult fxihtiesor the rtquimd I’w&tance estllblishcd for t=trd or mqm$abk syatexns & to high soil remstivity, rock formations, orothcr tmmi.aMureG,al~ mathods fbrreducin.g thcr=istancc toearth ahnllbemdered. Fw additional informatmn cm altornatc nmthods as wtdl as @t procedures, me MIL- HDBK+19.

5.1.1.1.4 Qround Rods. GrOundrOds ahaUbcOppr*Mti, a~ of 3m (10 W) in length, 6pactd

~@wmtiti* tidl*, dwwblmtil*h (3/4ti)hd~. Thctilickne$s of ti copper jackc$ shall not be bs than 0.3 mm (0.012 inch).

5*1*1*1*6 ~ Underground metallic pipeu altering a ficility shall be ~ tidy bonded to tbe building or facility catmncc plate whcz=wr Ulchcmmedms arc qtable to both the aemdng suppliers and the authority having jurisdiction. ‘Ihc cntmnce pti shall be bondod to the earth ckctmdc dlsystem with two minimum length 1/0 copper cables (me Figures 3 and 4). The intemmmch gcablesldudl be welded or bcazed to the earth electrode subsystem. Adequate corrosion prcvaItive mnamxcs ahal.lbttakom On ahiddcd bddings, the periphery of the entrance plti ahdl be bonded to the building ahidd. Structud *gfh *, d oticf lqp w@- metallic maaaes IK!uthcperipheryo fthe StXuc@malsoshallbe bondodin alike manncrtotitide subsystexm (See Figums18nd 2.) Utionti beusedwhcn

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SHOULD BE AS SPECIFIED IN S.1.1.4.2.

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NOTE: METALLIC FENCE /

SHOULD HAVE A SEPARATE

GROUND IF hKX?E THAN 2M j

/ w

(6 FT) FROM THE EARTH

C

ELECVWDE SUBSYSTEM<>

“ \ ‘LR;;;;R’:’ 1METAL PIPES ENTERING

THE FACILITY SHOULD BE

GROUNDED AT THE

FACILITY ENTRY POINT

Figure 1. Example of Equipobtid or Multipoht Grounding to Earth Electrode Subsystem for Overhead Piane

MIIATD-188-124B

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MXL-STD-188-124B

5.1.1.1.7 &wtarl Ce Ckcks . Tllemslstancc tooartboftboddti subq%tmshallbe~dy by the fdi of potdd techniqw. This shd be acmnp~ prior to the com#e40n of CCM@fUCtICXiof associated buildings and @rI=W=+. To assure adquate perfo~ under all climatic Conditions, n%’istancz Xwsuremelltso fthedeimti subsyutomtoearthwlblnadcd WeeumnthukklVdsforlzm& fbuOWU@XUddon. TIwte@wmfi@mtidh~d_kd~t mXsumwW. mtirmss ofsuchtesfsm be- soasto~ the adequacy of the earth electrode gubsystom over expected ranges of local ~ and precipitation. R~ mwumments of the earth oktrodesubsystemto-~~~~evq 2inxmths aftcrtk titi12wntiptiby the f=iJ’iti= ~ activity. For additional test inhmation, see MIL-HDBK-419.

5.1.1.2 ~uilt Pm&#on Su- .

5.1.1.2.1 w ~tidt-m~~mti@Ofa~-g~r@~)l ~ wtie - d =@Pt ~ a@inst power fad cametM8and $tAtiCcharge buildup. ~tion from lightning flashover shall be provided by grmmding all myor non a.rremt-camying lnetd objects, inchdlng main stmctud steel support members. Aground busstud.l be~~kdtiti= andpanehard.ssnd a- conrXXting gmtm&ng(grecn)’*w~ -wi~*- raceway or cable wxtb the ac powor calductors. T’be instalMon shall Confbrm with the rquimn= ts of ArticIe 250 of the National Ekztnud Code. Xnallmeasmquircd@mtim_ cation 15eulrity, equipment and power systems w be grmmded in acxmrdance With MIL-HDBK419.

5.1.1.2.2 ~uildin4@ru@nd Steel. All main metallic structural members (except reba.r) such as the kikiing cohmms, wd frames, and roof trusses of steel frame buildings and other metal structures should be rmde ekctxhxdly continuous and grouded to the Mlity gmmncisy8tean. W%cm5ververtical * is utilized to extcmd the facility ground sys$em, it shd be made eih~ly continuous and grounded.

5.1.1.2.3 ~and T@ms. Au required, aiI metallic piping and tubing and tie supports thereof sbou.ld b electrically continuous and shall be gmundcd to the fdity ground system. See Figures 3 md 4.

5.1.1.2.4 ~ ectricd slQpor@ “ fz Structure’a. Ebctrid supporting dmctura &d be ddrid])’ continuous and grounded to the facility ground 8ystern through the f&ultprotection sukyst.ern.

5.1.1 .2.4.1 ~duit, All conduit, whether used for power distribution wiring, or for sigmd and control wixin.g, shall be groundd in accordance with the following:

a. AUjoints between sections of conduit, fittings, and _ shall be ckanod in accordance with procedures in 5.2.8 and My tigbti. W mquimmnt for and use of conductive lubricant ~ bond members shall be detemimd by the electronic/el=tid eqtipmmt P@@ cnginc=s.

b. Cover plata of conduit fittings, pull box-, junction boxes, aud outlet box= shall b PM by securely tightening all svda.bie screws.

c. Chduit brackets and bangers shall be electrically continuous to the conduit and to the metal stn.wtures to which they am attached.

The rounding conductor (gnxm wire) may be comprimd of green, green with yellow strips, or bare*8 with green tape.

5.1.1 .2.4.2 ~ Tnws or Rwewavs . Theindividual aections ofallmeMlicdletmy Systomsshidibe boded to each otheq(andbto the msmmys which they “support. A@@haUy K@&nUoWbowia.ahidl be in acwrdance with the pmcodures and mcpkments specified in 5.2 through 5.2.8. Direct bonding methods of

5.2.6 are prefked. All metallic cable tray assemblies shall be cxxmected to ground within 0.6m (2 f- of each eadofthe nmandatinmndcx-g 15m(50feet) akmgeachnm.

5.1.1 .2.4.3 ~osufes M electrical and eiectmnic wiring d distributi~, equipment ezlclosums, not obrwisespecifically tiveredhuein,shal lbegrqldad. Thegmudingcond@or shall not

P- equipment cabinets Or cases but rather shall be termhtd Onaground atudperiphernlly weided to the metal barrier.

5.1.1 .2.4.4 ~etallic Power Glble shQf&& Medic cable sheaths cm electrical power cables shall be ~ toground at both ends.

5.1.1.2.5 ~ POW Sv@gZW lubktricalpoweniimibutioaayatemsahallbe~inwti with the following:

5.1.1 .2.5.1 AC D&jbuti~ Swtems . AC power distribution aysterns shall have the neutral conductor grounded at the distribution transformer and to the earth electrode subsystem of the fkcility. The size of the

_ _tor fmm the find ace disconncct means totheeurthektrode subsyatexn ahallbeas specified in Table 1-20 of MI.L-HDBK419 or Table MO-94 of the National Electrical Code. In each facility send by a common distribution tnmsftmner, the neutral sl@l be directly Cofmocted totimeamdpoi ntoftheearth ehxtrode subsystem. Where delta-wye system wmversion,is employed, the service entrance shall be a five-wire system consisting of three phase conductors, a groumkd (neutral) ~, ~a-g@=@ wmductor. IncachfaciMy,a Upowcrdidn_eti8 ahallbidatdfrw nthe C-EqiprIE@a and the structure demerits so @at no ac return current flows through the equip-t and fault protection subsystem or the signal fefercm-l network. The fault protection subsystem grounding (greea) conductor 6haIl be Wed inaccdam= withthe National Elticd GdefmaU C-Eequiprnemt. Conduit shall not beusedinlieu ofti

~ -8 (P=) -*

5.1.1 .2.5.1.1 $inde Buildiwz with Mdtide Power Sources. ~i grounded (neutnd) conductors shall be grounded at the tit service disconnect means of each source. For deha-wye conversions, a five wire system shall be_ fiwm each ~. Delta systems shall employ four-wire fmm the source, consisting of three phase conductors and a grounded conductor for grounding purposes.

5.1.1 .2.5.1.2 J$hltide Buddinm with Simle Power Source. Neutral conductors from multiple buildings being ildpower sourushdb egmundeda tthesoumedy. Illelleutralshaubeserviced from a singie comrnerc iaohtedatthe fi. rstdi sconnect mans. A five-wire system shall be utihzd hm the some.

5*1*1.2-5*2~ Motor and genemtor framea and housings till be grounded in accodancc with Article 250 of the National Ek@ricaJ Code. The genemtor neutral shall be grounded directly to the earth ebctrode aubsystern. When gcuerators arc mnected inpar’akl, theneutrdsw be ~ and grounded with a single ground conductor.

5.1.1 .2.5.3 AC O@@ . Grounding of recqkades and mmchted ~~wmti mquimmmts of Articks 250-’74 and ti~ of the National Bkctricd (b& (1984 01 k). However, ahmimun and copper Chd ahminurn cxmductors permitted by Article 2!$M ahd not be used. When nemssary to cmntrol noise problems, grounding of grounding terrnids may be accomplished IAW Exception 4 of Article 250-94. Grounding of me@lic outlet boxes shall not be dependent upon serrated strips or cl.qm

5.1.1 .2.5.4 ~ Md.m aud Genera tOr& ‘nkehme so fnmtors,genemtm, andother types of electrical rotat.ihg ma@wry shall be @ded to’lhe fit protdon subsystem, aeu!mhng to Artick 430 of the ‘National Elect&al Code.

5.1.1 .2.5.5 PC Power Sources . (lnekgofcach dcpowersyste mahailb egmundedwiths singkmnnection dirwXly totheearth ekctrodest#x@em. Tlwsizeofthc grounding inductor shall be as specified by ktiCk 250 of the National Electrical Code. mether _ at the amuce oratahmd,aa epamteummtmt urn fknnkdto thcsourceah allbcuacdto assureth atnodccurnmt flows inthefkult protection ortheaignal dbrcnce subsystem.

5.1.1 .2.5.6 ~~ RAcks. Metallic battery racks shall also be grounded to the ficility ground system at the neamt point.

5.1.1 .2.5.7 Qround Fault Circuit In ternmters. All 120 volt single phase 15 and 20 ampere mceptacie outlets shall use ground huh circuit inkrupters (GFCI) for personnel protection (See NEC Article 210 and 215).

5.1.1.2.6 &xure Facilities. All areas required to maintain mrmmmicatiom security equipmemt and associated power syatem6 shall be groundd in -dance with MIL-HDBK419.

5.1.1.3 ~ “on Subtwstem.

5.1.1.3.1 Gen~ Lightning prot=tion shall be provided as required fbr buiidingsamd structures m accmbce with the National Fire Protection Aamciation (NFPA) No. 78, and the following:

5.1.1.3.2 ~ Stnmumx Ligbingprotedonshal lbeprovidedas- fbrbuildingsand atrwtww in acad&ce wi@ ~ additions and modifications specified herein ~d the applicable paqmphs of NFPA No. 78. This pmtectiop shall be extended to all ckctrid, dhdmnic, or other elements which area put of, or am in support of all C-E facilities. Such elemmts shall include, but shall not be limited to, subamtions (to the extent that additional protection beyond that provided by the electric utiiity is neccamry), power pole, towers, antamas, masts, etc.

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MIL-S’ID188-124B

“’-J”

5.1.1.3.3 JkWn ~ where copper-clad steel dovm conductors ap used op @ructures not greater than 23m (75 feet) in height, &e dc Astake of solid wir& or stranded cables @@l not be greater than 0.176 ohm per 305m (1000 feet). On structures gmatcr than 23rn (75 feet) in height, the dc rwrhtance of the wire or cnhle dull not be greater than 0.088 ohms per 305m (1OW feet). The S* of wi- in co~+~ stranti cable shall not be less than Nd. l#AWG~ (In cases where mechanical and installatkm duations warmnt, a larger

(prefembly No. 6 AWG kqpr) w my b utiIM.) W coppr cwcring of @ cop~-dti s@ down conductors shali be qerznanently and eff=tively welded to the steed core. The conductivity of copper- clad wmductora shall ~t be leas’- 30% of ‘a adid copper conductor of equivalent croq-sectional area. Down conductors bends * bb gfadwil and not have a radius bs than 20cw (8 in). ~ apglc ‘of any bend shall not be less than 90 deg~ (see-:Fi@e 5). “Any metal object within 1.8m (6 feet of,,* ,li@tning download shall be bonded to the down conductor (see NE!C Artic$e 250). where practicable, ● ~tion of ~ least 1.8m (6 feet) shall be maintied ti{bj)edtintitors Ofipower and cmnrnuni~ons Syq and ,ti@tning down ‘ conductors (see N@ ikitic~e ‘800j. “On $tr@ums‘ higher W 18m@l fe) there shall be at leasi one additional down conductor for “each additkmal 18m (60 f-) of height fractions @aof, ex~t ~t the interval between down tiductoti around the @rhieters shall not b less than 15m (50 feet) nor greqtor ~ 30m (100 f~).

Down conductors shali be continuous and shall be bonded in accordance with 5.1.1.1.5 and 5.2.3 to an earth electrode subsystem or to a ground rod bonded to this subsystem installed as near as practicable and within 1.8m (6 feet) from the stmctum.

I

Radius of bend:

wt k than 8“

L

L

The angle of any be lass than 90° bend shall not

\B

Figure 5. Radius and Angle of Down Conductor Beads

5.1.1.3.4 ~ Al ixds be@xm@ern@g of X9 ugh~g p~@tion ~~y~~ s~~ ~ -de bY welding or brazing or UL approved high cornpresaion clampmg dcvicms. Wekimg or brazing shall be used for all bonds not readily accessible for inspection.@ maintcamnce. Soft solder shall not be used for bonding any conductor in the lightning protection sub8ystem.

5.1.1.3.5 -ml steel , Substantial metal structural elements of buildings and towers (including overall buikiing shield whore it exists) shall be acceptable substitute for lightning down conductors provided they are permanently bonded in accordance with 5.2 and bonded to the earth electrode subsystem. Bonding straps across all structural joints shall be IAW 5.2.3.3.1.

II I 11 11! 1,

5.1.1.3.6 ~ T-Is i~ Rw Non-rrmtdiic objects, p@enaions, or protrusions requiring protection ~ have the @r termids designed and installpd $ acco$ance with r@rwncnts of NFPA No. 78, Ch8ptUl! 3-9 and 3-10.

-k-..=--

MXL-STD-188-124B d\

5.1.1.3.7 Gualds, W’hem conducW“eguuds must bcuwd, thegurds @l,& ekctricdybondccitit=hcnd of the I!@210aeti’t@htningux@QcmY. B8eh--’S!!JctioKruf UmducWe“ ‘gtTaTtk’llhlumkMYbe bondaI-(u’the

W-~.

5.1.1.3.8 ~ , Iightai.ng pmtaction Shall be pvided for radar, Coxnlxmaiatkxul or migrational aid mtama towers, and similar suppdng strwmuw in accmkce with the fcdbving:

5.1.1 .3.8.2 ~r ~ Anairtaminal shdlbeinstalledonb towcras spocificd in5.1.l.3.6. A minimum oftwooondudive psthstihal.1 exist between anytwotitmninak and bdweenany ai.rtaminald ti*4~~(w~ti H=& bti5m(16ti)).

5.1.1 .3.8.5 wave Groun~

. Ass minimum, all Waveguidul shall be grounded as folb’vm:

8. Aliwmeguid8u tothouMmlMls 6haubf3gKnmdod &tk*. Hthc~ ~~-+ horimntal tnnsitionncar thcbascofthetowcr, andatthc wavegui&@r’yp@

b. hk@ic supporting stmdums fmwweguidcss hdlbcclectridymti d~k~to thecxtwior cuthckctrodesubsyh atti.wfirst 8ndktsupportcol~m ● minimum. Th18wirekdclihaU bowiimctwpo=i%lo.

C. Wmguicknhallbegmundedtithsolid~ stnporcq%% wircatkar@e@bNo. 6AWG.

llmsiaeofwimc intMuabk,ahalbtbk tiNo. 14 AWG. Br8idcw fiarx~wireth=No. 14 AWGaballnotbeumd. A.llbcmdsofground~ shall baveamdius of Xkm(8in)m~dk utgkofany bl!Dd&llnot bekeatimn90dqp=.

5.1.1.3.10 J2xten“w’Wirw ~d Ckbies.

!,!,.,, .Ilf

5.1.1.3.10.1, #t.i ~m=ion~ steel conduit shall be used to ~-y enclose msceptible wiring (notably outdoor or ‘~k&md signal wiring not otkwise pmtoctd) 6 @i4d ●- U@tig a fi~tig induced currents shd voltiges. Such conduit shalJ be ehxtrically bonded frbm aoction to section with oorrosion-pmtectd mmpmksiti’fittirigs or ,shall be welded or brazed 8t each joint. Pull boxes,’junction boxc6, eti. that are integml to the cobchknd ektrkdly boded to the conduit shall be regarded as conduit. MM rnmholds, Whcreuoed, shdibetitobe-tit. Non-me@llic rnanMm WhMd@ti~&a~ eloctxical @h 6 one section of @tit to other sections of conduit cOtering or leaving ● manhole. The amduitdwllbebondedat-d totheeiuth ek@rodesubsy_of=h tormbtm ‘ g fkcility.,, *I ,

5.1.1 .3.10.2 Overhead Guard win% @rhemdguudwimAallbero gaded 8s8irtmminaIs. SucJlwi.res b shall be qwed not~kw & Im (3 f-) above 8ny signal or control cixxmitsbeing pmte@xi. The minimum wmductors imshaUbel/OAWG@v~ std. Ovtiguard &shaUbCPti totheeartb ektrode subyst(diof ckh twmi@ing (250 feet) 9the~hwkb intervals not exceeding 76m (250 feet).

grade Acvel.

5.1.1.3.11 Under mxirki Guard Wires.

facility. whim the di- bet-en tmnhAILg f=iWXI COK* vbm bonded toaground mdrneeting thcra@ren=b of5*l.1.l.4ti ~@of&pti tiWin@&l=ti O.3m(l foot) bekw

Buried signal, power, or control wires or abl= not otkwiae protected by f-us conduit in the manner prescribedby 5.1.1 .3.10.1 shd be protected by s bare 1/0 AWG

@PP%@- embeddd inthemil above and parallel tothewirc6, cabJc60rducts. Tk~ wim shall be laid a minimuxii df145cm (18 in) below grade kvel and at kast 25cm (10 in) above the duct or ~ wireorcmble. ,~the~dthof~ ductorthe spmdofthecablem - notexceed lm(3feet), one guard wimeemter@O+ik the_~qblewti&tid. Where theapr=dex- lml(3f@, ti pfdfJ&J~l*,l& ~W,h~Uim 3-(12 ti)lXd Wl=~h(12ti)m nmre ban&# (181@riside the qt&&@ wik’oHheai gurofthe@@bark Aliguud wire$shallbe bonded 8te+h&&#ti’Ui&euthektr@e Iksy@en’ofeach tamiklg~ty: =~ tdmodfbr undetgrOund gwlk+vir& dh8Ubde@mild by the electmnickkctricd pquipmmt *=*&j ti&mtim=

- activity &rld8h811beckmined m8eaeand ioc@kmbaZlis ~ ~ +Ititity of the tit d the degree of lightning an&ipatcd.

5.1.1.3.12 ~ Expo6ed andundqmmd power lim, not pr@dedtitiuL -i@* armstom 8tthepoiat ofantnnca iritothdk%lity. The mmrtomwbe installed in&X&nce “ ‘ iVithi~C~ ~ of the National Electrical Code @m!MIIAIDBK419. (if a conflict tid~~ti~Cd&~,tim_~dwly.)

“k---’”

MIL/-STD-l88-l24B

5.1.1.3.13. e~ R41SS& Aliuecurity orperimc@fm outlined m MIL-HDBK419.

5.1.1.4 ~ RefereinQ Subs-

5.1.1.4.3 -r F~ueaw Ndwork . A iowcr ~llOllCy rletwolk ti be tid U fkditk ~]OYi.IIg ioworfrequency @p~tskm&to 30~andinaorneca8es~3@~. Theptupose oftbis~is to inohc X fiequmcy tigrds from dl other ground networb inchld.ing structural, safety, lightning and r-” ‘rllhne$wrkpnw=-my mmukts (primarily 60 Hz) him developing voltage potentials b@woeapoints onthe_~ti. Thislowerfr cqueocynetworkmWk canectd tothoearthde@ode subsystem 8t one point cmly (single point) 8nd mu@ be cmfigumd to minirnk conductor poth kmgdi.

Additional information on lower fkqueacy ndworks m be obtakd km MIMIDBK419.

5.1.2 @_ “cations-ElcctroQ)“m {C-E) ~rneau) t.

5.1.2.1 ~ Refbmxm Su_ This subsystem provides the vokage m- pOiM(s) for ~ &@

5.1.2 .1.1.1 - Isoh#tioll. There cball be no isolation betweaa equipment chassis and case fa higher

~WXWy equip-~ except where stated in 5.1.2.1.1.

IWIXAT’IH88-124B

S. 1.2.1.1.2 w~$l-1 tiud T_im. Each individual unit or pi= of equipment &all eithex be Wtoitsradcor~bm@m SCUmboe wtth5.2.40r akdl have itscase orchasisbond edtothenti point of the equipo@mti~ plane. M and ~ti shall also be groundd to the equipotcntiaJ plane with a =qq=q. A.lle@p=t c==dd*ddtiw have a grounding tmninal, as long as it permits convenient and aecum attxbmmt of theground strap.

5.1.2 .1.1.3 ~eld T~ of _ an d ~ FreqyQocv - Allconnectors ahal.lbe ofa

~@hi@tit~ti& aIm_@@@m titi@bti4d@*~ta. If the signal circuit must be iadatcd ffom the equipment use, md if the ahiekiing effectivencas of the case mnst ti be degraded, a cmmector ofatrkxial -that pppdy groun&the outer cable shield to the case shallbe used. ShieMs of coaxi81 cables and shielded balanod transmission Iinm Aall be @mina@d by Pef’iphedy

-tig b shi~d to the eqtipmt m. Boding of amnectom shall be m aomrdancc with 5.2.5. Coaxial shields and ~h~~hetijti mkxa, ~~,rn~-~mbxed other in@mmwctl “on pornta alomg the aignas path.

NOTE: Signal and control cable should be mpamted from power cables as fir as practicable.

5.1.2 .1.1.4 Ove@l Sluelds, Shields surrounding a cable containing individually shielded lower fkxpwacy signal - or containing only unshielded lines shall be grounded at each md and at junction boxes, patch panels, distribution points and at other intermediate points along the *le nm. Overall tiehis shall be grounded to cases, cabinets or conducting surbc=$.

‘u’

MTL-STD-188-124B

Ui

5.- I&

5.1.2.2 Ftudt protection Submtem .

I

5.1,2.2.1 @twral. ‘Thefault protection sbrystem amums thatperaonnehr eprot=t@f romt$mckkmmrda I@ theequipmmt ispmtectd ftorndunage ra@ingfiomftits,inc hding8hortckuits thstrn8y deveAopinthe dtid~iyd*Mm -omw~-h~titi*-~b fkility except for one point of interke st the power fi cmtxy. (See 5.1.1.2).

5.1.2.2.2 pemorlne lPr@eqQ& MemsshaU bep&idedbywhichti @@P=@ * * ~ -J ~v~~ knobs, switck, d comu@Om that are s@ject to’human contact during Bormal opemt.ioa @ main~ me gmtndedb-ti ti~tidy -h —ofebmtim~ fkihlmu. All mmtacts, tednala mXllikedevioD8 h8vingdangcmm vdt8ge6dmll beguard@d fmrn=cide@I contact bypmonnel ifsuch points are expoeed tocontact during di.mct~rtofe mainkmn .

Ground Fault Circuit Intemptcm (C3FCI), inlltdied on Convcskloe * u qmcMd ~ 5.1.l.2.5.7~ b National EIc@ric Gde Article 215, should be utiked.

5.1.2.2.3 AC Power Neutml ~ In all electrical and ektronic equipmmt, the ac power neutral (white wire) shall be insulated fim the equipment chassis, case, and fkcility ground system axcxpt for one point at the ficiiity power service catry. With the circuit breaker open arid the neutral disconnected, a rnimmum of 1 rnegohm & resis~shall cxist~cithcr tide of theachne andthe@pmmta _).

5.1.2.2.4 ~ividual Power ~

Fil ~ Allpower l.inefikenasesshallbedimctl ybondedin acomhXewith

5.2 to the equipment m or mckwure.

iJ

5.1.2.2.5 @s. Where AC OUtiets8re pmtidd with =@P=Qt of ~uiP-t ~J ~Y quimments of Articles 250-74 and 250-94 of the National Electrical Code (1984 or Inter). However, aluminum and copper CIMIaluminum conductors permitted by Article M&94 shall not be used. Astheee outJetn Breimmed@e“ lyamwciataiw ithequiprnlwlti nstdedinmclm Ormhnets,thleyshnllnot beu8edfbr powering 8nyext8rn81 equipnxmt excuptthatu6ed forrnaintemnce mxitesting ofequipmcmtinthe Cabinet orracks.

5.1.2.2.6

.~ Portnlde electrical or electronic equiprne+ntcases, enckums, md kusings W be considered to be adequately grounded for pemonnel protection through the third wire (gmmding) of the power cord provided that continuity is firmly receptacle’s ground terminal Tlw third wire established bctwecm the case, enclosure, or housing and the of the power cord shall not be used for signal ground.

11, !

II I

1-

‘u’

I

MWS’I’D-188-124B

5.2 J30rdinL @Of Buikhg, s~, and C-E Equiprneat InatalMons).

5.2.1 - -mtimb~by~ak~~titi--~’-ti cummtise@ablished~W_c o@jccts. In,anytic’~cNw,~ itiamlyonc piece of equipmcmt or an ti we. n~ ~ “cmsbdweul m@iico@jectslmn$be bin Orderto minimk electric ah’ockbam’ds, & I@ling pmtec!ioa, @xMiah referemas fill dectmmic signals, etc. Ideally, each of tllcae hkmmctl “onsabould bcnmdcao thatthemdankd and ektr’ialpmpertiesofthopa’th=e~ “ ~the ,pmnectd rnernbmand not bythcirlt=wm=tl “on junction. Further,tijoti’~tihiti- ov~anex~’~oftiinti toprwvent pfo~vc ~e~ tim ~t M- _ c=mc=im of mecbamdkmocmaa. Intalrlsof tkresults to beachievcd,b ondingisne==’y forthcfbllowing r’cmns:

a.

b.

c.

d.

e.

f.

Pro&&Xlofequiprnrmtd prsos=lf fomti-ofM@Q@l~”

Eatabiildlmmt of fiult Curralt retuln paths.

13stablishmcat of ~ and @able paths for ektrical CurI’catll.

Minimintmn of VO~~ on mchsums and housin~.

IWXtion ofpemolnd fNJ’mahock hazards.

Prevention of static charge acc41m@tion.

5.2.2 _ P~

Sur’fkoetmatll=ts,wtipwppwf=w~~ or corrosion promctiinl, & Off8r lli@lco@ucti~. Phtirlg’nlctalu ,haif be

~Y -Me with Q the baaernetals. unkasmlitabiypro@tedti ti~, $iIvcrand othlero@y tmni$dm@sw not bcdt@atetbebaMi~.

5.2.3 Jkmd Prvtecta“Onz AU bonds CXCC@ tkXW Mod in 5.2.3.2 H h ~tilY _ X ~) tive @moqbms, vibrations and mechanical -e. u- @ ~~$ a Corrosion preventive or sealunt All be applied within 24 ho~ of -~y of b = ~t UX h@ tid.i~ 4-, malingoftbe blldshaltbe~ tithk one hour of joining.

5.2.3.1 @rosicm Pxvtcctlon . Each bonded jOiXltW be protocted a$@st…