Table of Contents
1Generalconsiderations
1.1Originofdangerousover-voltagesand
over-currents
1.2Methodsofprotection
1.3Typesofprotectivedevices
1.4Residualeffects
1.5Assessmentofrisk
1.6Decisiononprotection
2Protectionoflines
2.1Protectivemeasuresexternaltotheconductors
themselves
2.2Specialcables
2.3Useofprotectivedevices
2.4Installationofprotectivedevices
2.5Planningofworks
2.6Recommendedpolicy
3Protectionofexchangeandtransmissionequipment
3.1Needforprotectionexternaltotheequipment
3.2Needforequipmenttohaveaminimumlevelof
electricalrobustness
3.3Effectofswitchingconditions
4Protectionofsubscribersterminalequipment
4.1Degreeofexposure
4.2Dielectricstrength
4.3Useofprotectors
4.4Commonbonding
4.5Highisolationtechnique
4.6Nationalregulations
4.7Highcostofmaintenanceofsubscribers
installations
References
AnnexADefinitionoftermsassociatedwithprotection Abstract
Gives specification for limits and requirements for measurement of the levels of spurious signals generated by equipment at the ISDN basic access interface to protect radio reception. Applies to equipment intended for operation over twisted pair wiring and cables (unshielded or with metal sheath), specifically, NT1, NT2, TE1 and TA having interfaces Ia or Ib at the S, T or S/T reference points. Also provides limits for common mode voltages and currents at telecommunication line ports are given for the for the frequency range of 0.15 to 30 MHz. For limiting values at main terminals and for radiated field strength relevant CISPR publications are referred to.
