ITU K.25:2000
ITU K.25:2000 Protection Of Optical Fibre Cables The protection against lightning of telecommunication lines in fibre optics installations is the scope of this Recommendation.
Table of Contents
1Scopeandobject2References
3Definitions
4Referenceconfiguration
5Constructioncharacteristicsofthecable
5.1General
5.2Failurecurrentforburiedcableoraerialcable
withearthconnectionsofthemetalsheath
5.3Failurecurrentforaerialcablewithoutearth
connectionsofthemetalsheath
6Needforprotection
7Protectivemeasures
7.1General
7.2Dielectricormetal-freecables
7.3Choiceofcablecharacteristicsforbothburied
andaerialinstallations
7.4Useofshieldwireforburiedcables
7.5Routeredundancy
ANNEXA-Frequencyofprimaryfailures
A.1Buriedcable
A.2Aerialcables
A.3Cablesenteringastructureexposedtodirect
lightningstrokes
ANNEXB-Sheathbreakdowncurrent
B.1Buriedcable
B.2Aerialcable
ANNEXC-Testsforsurgecurrentresistivity
C.1General
C.2Breakdownvoltagetest
C.3Sandboxtestforburiedcables
C.4Testforaerialcables
APPENDIXIShieldingfactor
I.1Shieldingfactorforoneshieldwire
I.2Shieldingfactorformultipleshieldwires
I.3Minimumlengthofburiedshieldwires
APPENDIXIITolerablefrequencyofprimaryfailures(Fa)
APPENDIXIIIEnvironmentalfactor(Ke)
APPENDIXIVBibliography