ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Fibre Protection and Cables

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Overview

Basic fibre protection

Fibre types

Basic cable construction

Fibre protection in cables

Typical cables for different applications

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Fibre ConstructionCore and Cladding are normally made of silica glass

Bare fibre is very rare

Fibre is always protected by buffer jackets

Further protection is provided by an outer cable assembly

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Primary Coated Optical Fibre

250-300microns

Primary Coating

FibreCore

FibreCladding

Primary CoatedOptical Fibre

End product of the fibre manufacturing process.

Cannot withstand excessive bending or twisting, so it is unusable as a fibrefor installation.

Widely used as a basic element within more complex cables

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Secondary Coated Optical Fibre

Primary Coating

FibreCore

Primary CoatedOptical Fibre

Secondary CoatedOptical Fibre

Typically 900 microns

Secondary Coating

Features an additional layer of plastic on top of the PCOF.Can be used as jumpers or for short fibre interconnects

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Coatings and StrippingFibre coatings

Primary coating: Usually Acrylate, 250mm diameterSecondary coating: Silicone or Nylon, 900mm

Stripping ToolsHand-held, mechanical, eg 'Augat', ‘No-Nik’, ‘Miller’Various fibre dimensions catered for, normally presetChemicals, careful handling needed

No-Nik

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Ruggedized Optical Fibre Cable

Primary CoatedOptical Fibre Secondary Coated

Optical Fibre

Optical Fibre

Single RuggedizedOptical Fibre Cable

Diameter 1.5 to 4 mm

Yarn based strength member, (Kevlar or glass fibre)

Neither PCOF or SCOF can be directly terminated with demountable connectors.

Some form of strength member is required, most basic form is shown below,called a Single Ruggedized Optical Fibre Cable (SROFC).

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Fibre TypesThree generic fibre types dominate the building cable market

Multimode is most popular but singlemode is now being installed more frequently

Multimode is more tolerant of source and connector types

Singlemode offers the largest information capacity

125 micronscladding diameter

62.5 micron core diameter

50 micron core diameter

8 micron core diameter

Multimode fibre

Multimode fibre

Singlemode fibre

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Fibre Cables

Simple cables for benign conditions

Distribution cables in buildings

Inter-building cables

Non-metallic cables

Cables for underground ducts in telecoms systems

Directly buried cables

Overhead cables to be hung from poles

Underwater cables

When fibre is used in a normal environment protection beyond that provided by PCOF or SCOF is needed.

A wide variety of cables have emerged to provide different levels of protection

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Building Fibre Cable TypesTwo basic types of cable design have evolved for

optical fibre systems

Loose Tube Construction

Tight Jacket Construction

Cable consists of one or more tubes containing fibre

Fibre can move to accommodate stress

Typically used over longer outdoor distances.

Rigid cable design less suited to tight bend radii

Fibre protected in a tight structure

Less rigid cable design suited to tighter bend radii.

More modern cable design, offering higher fibre count

Most common building cable type

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Cable ConstructionLoose Tube

ConstructionTight Jacket Construction

Tensile strength

Crush resistance

Prevention of moisture ingress

Non-metallic construction (useful if problems with earth loops are to be avoided)

UV exposure resistance

Resistance to damage by chemicals, hydrocarbons etc.

Easy access to fibres and fibre identification

All cable designs to a greater or lesser extent provide:

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Protection: Tensile StressPCOF or SCOF cannot handle tensile stress

A variety of techniques have evolved to give cables tensile strength

Maximum tensile strength specified in Newtons

Steel central strength member covered in polyethylene

Non-metallic central strength member

Non-metallic central strength member

Aramid (Kevlar) Yarn strengthening

Pirelli

BICC

BICC

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Protection: Crush ResistanceNeeded to prevent mechanical and rodent damage to cables

A variety of techniques have evolved to give excellent crush resistance

Steel wire armour

Steel tape armour

BICC loose tube steel wire armour external

direct burial cable

BICC loose tube steel wire armour external direct burial cable

Steel central strength member

Steel tape armour can provide the

same protection as wire armour but is

lighter

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Protection: Moisture IngressMoisture can enter a cable in one of two ways:

Through the cable sheath if is damaged during installation

Through the cable ends (at underground cable enclosures for example).

Several methods of preventing moisture ingress exist

Metallic (aluminium) foil water barrier

Waterblocking gel filled fibre tubes

BICC loose tube, external duct cable

BICC loose tube, non-metallic external duct cableIntersititial spaces

filled with gel

Combinations of metallic moisture barriers and waterblocking gel can

be used

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Types of Building Cable

Patchcord cables

Distribution cables in buildings

Breakout cables

Inter-building cables (ducts or buried)

Non-metallic inter-building cables

External/internal duct cables

A very wide variety of cables have evolved for buildings:

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Simple internal cablesSimple cable structure, non-metallic

Can be directly terminated

Patchcord, point to point applications

Simplex version Duplex version, also called figure of eight

or shotgun

Duplex version, also called duplex flat

twin

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Tight Jacket Premises DistributionTight jacket construction, typically 2 to 32 fibre count

LAN backbone applications

Vertical and horizontal applications

Loose tube is sometimes used but this is not the norm

Low smoke zero halogen (LSZH) sheath

Non-metallic strength member

Tight jacket premises distribution cable

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

External Duct and Direct Burial CablesLoose tube construction, typically with gel filled tubes. Alternative is a metallic moisture barrier

Loose tube construction with armour for direct burial, will also include moisture barrier

BICC Loose tube external duct cableGel filled individual tubes

Steel wire armour

BICC loose tube steel wire armour external direct burial cable

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

External/Internal Duct Cables

BICC Internal/External Loose tube duct cable

Extruded dry LSOH waterblocking compound in interstitial spaces

Gel filled individual tubes

Internal to external transitions may involve a change of cable, requiring a splice tray and closure

External/internal cables are available which have both moisture protection and low smoke and fume zero halogen and UV stable sheaths

External/internal cables can reduce number of cable transitions

Useful for reducing the cost of short cable runs between buildings

ADAPT is a Human Resources Community Initiative supported by the European Union through the European Social Fund (ESF)

Summary

Fibre is produced as either PCOF or SCOF

Fibres with a variety of core/cladding dimensions are available

Basic cable types are tight jacket and loose tube

Cables will incorporate protection against tensile stress, crush damage, moisture etc.