IEC 61758-1 pdf download – Fibre optic interconnecting devices and passive components – Interface standard for closures – Part 1: General and guidance

IEC 61758-1 pdf download – Fibre optic interconnecting devices and passive components – Interface standard for closures – Part 1: General and guidance
The interface between the cable and the closure as well as cable/closure installationtechnique shall be designed to minimize additional losses of the fibre optic link.
Cable termination fittings are an integral part of the cable installation technique and shall beconsidered also.
8.2.2Cable entry port
Cable entry port is defined as the transition point from the fibre optic cable to the fibre opticcable termination.The cable entry port design depends on the cable type, in particularwhether the cable sheath type is metallic or plastic. The dimensional correspondencebetween the cable and cable entry port diameter shall be defined according to the installationprocedure and sealing technique.
The number, form and size of the entry port depend on the closure type facilities;.joining
-branching:distributing;
joining of the cable and cable entry port;
pressurised or non-pressurised cable installations;realisation of the gas and water tightness;
crush and tensile stresses;
shrinkage;
expanding port capacity.
8.2.3Repair, maintenance and testing
Repair and maintenance activities are necessary to allow upgrade of the fibre optic link aswell as proper functionality of the fibre optic link during its lifetime.The cable terminationprocedure and accessories shall ensure the reinstall of the cable/closure connection with thesame performance as before the repair and maintenance activities.
Repair and maintenance as well as the testing procedure depend on the optical networktopology:
ring;star;
point to point;point to multipoint.
8.2.4Moisture and gas ingress, sealing and blocking
Additional cable seals may provide the facility to prevent air，gas，water，cable grease orcontaminants entering the closure through the cable.A frequent cause of fibre optic linkfailure is moisture ingress into the cable core.The following aspects shall be considered;
sealing procedure between entry port and cable;
-cable seal(llongitudinal seal).
8.2.5Mechanical impacts
The possible mechanical impacts onto the cable/closure interface related to the cable entryport are as follows:
tension or pressure (axiall forces);shear (radial forces);
bending:
torsion.
8.2.6Cable and closure handling
Cable and closure handling shall be designed to cover the following aspects:-prewention of the moisture ingress;
consideration of the mechanical strength of the cable;temperature and humidity during the mounting.
8.2.7 Electrical continuity and lightning protection
Optical fibre cables containing metallic elements are susceptible to induced voltages andbeing struck by lightning. Induced voltages and energy dissipated from the lightning strike onthe metallic elements of cables can reach magnitudes which may cause damage to the cableand/or be a safety hazard to personnel in contact with the cable.Local regulations must befollowed and some of the following aspects may be required:
electrical interconnections between the cable metallic elements;
.all accessories for maintaining electrical continuity shall withstand the environmental
impacts related to temperature, humidity and wibration;
external grounding of the metallic components of the cables and metallic parts inside the
closure;
electrical continuity test access point，to verify that there is an adequate electricallyconductive path.
8.2.8Fire-related performance
The recommendations for the requirements and test methods to be specified for the fireperformance of the cables when installed in buildings are defined in lEC TR 62222.
8.2.9 ldentification of cables and sub-parts
The fibre and cable element identification for fibre splicing at cable joints or connecting atclosures shall be defined.Fibre or cable elements shal be easily identified by colour, markingor position within the cable core.
The fibre and cable element identification marking shall be reliable:
. if a colouring method is used, the colours shall be clearly distinguishable;
the colouring shall be stable in the presence of other materials and compatible with themduring the lifetime of the cable;
.application technique shall not affect any transmission characteristic;
the colouring or marking may be in the coating or applied to the surface of the coating.8.2.10Biotic protection
The material choice ensures that the external materials of the cable/closure joints do notsupport fungus or any other microbiotic growth.