Motorola GTR 8000 - General Battery Installation Recommendations; General Breaker Recommendations; Table 3-2 Heavy Gauge Wire Resistance Examples

GTR8000BaseRadio
•AllACpowerequipmentandelectricalcomponentsmustconformtoNationalElectricalManufacturers
Association(NEMA)andNationalElectricalCode(NEC).ThesemustalsobelistedbyanNRTL.
•Asurgearrestor,designedtoprotectequipmentsystemsfroma120/240Vserviceandloadcenter,isplaced
onthepowerfeedaheadofallindividualloadcentercircuitbreakers.Thisgaplessarrestormustbelisted
byanNRTLforthepurposeintended.
•Selectionofasurgearrestorisbasedonthesusceptibilityoftheequipmentpoweredbytheelectricalservice,
withmarginprovidedforlocallygenerateddisturbances.SeeANSI/IEEEC62.41(21)formoredetails.
•Atleastone120VAC,15Aduplexconvenienceoutletequippedwithgroundfaultinterrupter(GFI)
protectionmustbeprovidedintheelectronicequipmentcompartment.
Donotusesurge/transientsuppressorswithoutcarefulandexpertpowersystemanalysis.
SUGGESTION
RedundantdevicescouldbeterminatedondifferentACmainphasessothatasinglephasefailuredoesnot
resultinapowerlossforbothdevices.
3.3.8.2GeneralBreakerRecommendations
Inordertoensurethatafaultwhichcausesthebreakertoopendoesnotresultinthelossofmultipletransmit
channels,eachbaseradiopowersupplyshouldhaveitsownsupplybreaker.ThebreakerrecommendationsforAC
andDCsupplybreakersareasfollows:
•Fora120V AC,60Hzapplication,theACsupplybreakershouldberatedforacontinuouscurrentof
20A.Fora220V AC,50Hzapplication,theACsupplybreakershouldberatedforacontinuouscurrent
of10Aminimum,nottoexceed20A.
•IndividualDCbreakersarenotused.ForinformationinvolvingthesizingofcablesandDCpower
distribution,seetheStandardsandGuidelinesforCommunicationSitesmanual.
•SiteinstallationshallincludeasinglecurrentinterruptingdeviceontheDCinputdistribution(fuseorcircuit
breaker)ratedfortheapplicationloading,nottoexceed200A.Foreachstandalonebaseradio,theDCsupply
breakershouldberatedforacontinuouscurrentof25A.
3.3.8.3GeneralBatteryInstallationRecommendations
Thebatteriesandchargershouldbeascloseaspossibletotherectiersystemusingthecables.Aheavygaugestrandedcable
isadvisedtominimizevoltagedrop.Examplesoftheresistanceofsomeheavygaugewireis:
Table3-2HeavyGaugeWireResistanceExamples
Gauge
Resistance
#6gauge
0.3951/1000ft
#4gauge
0.2485/1000ft
#2gauge
0.1563/1000ft
Themaximumvoltagedropcanbecalculatedbyknowingthepeakcurrentdrawnbytheradiosystem.Usethe
followingformula:
3-126871022P86-A-November2012