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Direct Buried cable TECHNICAL SPECIFICATIONS We would like to comment the technical aspects as follows: Our proposed offer fully complies with ITU-T G.652, IEC, EIA standards and has the

Direct Buried cable TECHNICAL SPECIFICATIONS

We would like to comment the technical aspects as follows:

Our proposed offer fully complies with ITU-T G.652, IEC, EIA standards and has the following characteristics:

CABLE DESIGN

- 2 96 fibres

- Operating wavelength at 1310nm and 1550nm

- Non-metallic central member

- Loose buffer tubes (dual layer design) SZ stranded

- Interstices and buffer fully filled

- Dielectric strength member

- Inner PE sheath

- Corrugated steel tape for superior rodent protection

- Outer PE jacket

- Suitable either as Direct Buried and Ducted application (DB)

OPTICAL AND MECHANICAL CHARACTERISTICS OF A SINGLE MODE FIBRE

Effective group index of refraction Neff(1310nm): 1.4675

Effective group index of refraction Neff(1550nm): 1.4681

Attenuation at 1310nm (nominal): 0.34 dB/km

Attenuation at 1550nm (nominal): 0.19 dB/km

CORE MATERIAL

The core of the fibre optic, with a higher refractive index compared to the cladding, is made of SiO2

(Silicon dioxide) doped with GeO2 (Germanium dioxide)

CLADDING MATERIAL

The cladding of the fibre optic is made of SiO2 (Silicon dioxide)

TYPE OF PRIMARY COATING

The primary coating is made of an UV-curable acrylate It is applied in two layers, each of a different Young’s modulus The inner layer is somewhat softer than the outer one

This coating protects the fibre against microbending losses and against abrasion

Fibre color coding:

DIMENSION OF PRIMARY COATING

The dimension of the primary coating is 250 µm ± 15 µm

MECHANICAL CHARACTERISTICS OF THE PRIMARY COATING

The primary coating is easily strippable by means of a mechanical stripping tool No chemicals are required

MECHANICAL CHARACTERISTICS OF THE FIBRE

BUFFER TUBE TECHNIQUE

In the loose buffer tube technique the primary coated fibre is accommodated in a secondary coating, called buffer tube

The buffer tube may contain one or more fibres; the fibres are loosely laying in the tube, statistically

in the center of the tube

Due to stranding of the buffers an overlength is produced

(The overlength depends on stranding radius, tube diameter and lay length)

That means if a tensile force is applied to the cable, an elongation in a wide range will not result in fibre strain and no attenuation increase is observed

The loose buffer technique is also coping best to temperature induced contractions or dilatations of the cable The structure is as well a good protection against transverse compression

As a result the whole cable construction is, within a wide range, insensitive to external influences

REVERSE LAY (SZ) STRANDING

The elements (loose buffer tubes and if necessary filling elements) are stranded around a central member according to the reverse lay method, which means, that the direction of stranding reverses after a predetermined number of revolutions

At the reverse point the elements are laying parallel to the axis of the cable

A binder is wound around the elements in order to retain them in the proper position

MANUFACTURING OF A DIRECT BURIED FIBRE OPTIC CABLE

Around a FRP (Fibre Reinforced Plastic) central member, buffer tubes and if necessary filling elements are stranded to form the core of the cable

The central member serving mainly as anti-buckling element will be overcoated with a PE jacket if required, to obtain the correct stranding radius

The buffer tubes contain up to 12 fibres and are filled with a paraffine oil based filling compound

Color coding

As well the interstices of the core are filled with a filling compound in order to block any possible water ingress

Aramid yarns are then stranded around the optical module to provide the required tensile strength

An inner PE sheath (nominal thickness 1mm) is extruded above the core covering

A corrugated steel tape is longitudinally applied over the inner PE sheath with an overlap The corrugated steel tape has a nominal thickness of 0.155 mm and 0.4mm above the corrugation; both surfaces are coated with a copolymer, each one 0.05mm thick The corrugated steel tape acts as a rodent protection

Finally an outer PE-jacket (approximate thickness 1.5 mm is extruded)

Please refer to the cross sectional drawing which we enclose

MARKING

The marking of durable quality, is printed on the cable at regular interval of one meter length The type of legend marking on the cable is as follows:

DELIVERY LENGTH

Nominal standard length of buried cable in each drum is 1Km ± 10% or multiple (2,3,4,5,6) unless clearly specified at time of ordering

The wooden drum is non-returnable and will be marked with arrows to indicate the direction of rotation

Each drum will have a reel label with the following information:

Drum No

Batch No

Type of cable

Cable code

No of fibres

Cable length

Inner end marking

Outer end marking

Gross Weight

Year /Month of manufacture

TECHNICAL CHARACTERISTICS:

Cable type: A-DF(ZN)2Y(SR)2Y

Min bending radius

- during installation

- installed

[mm] [mm]

315 285

365 330

400 360 Tensile strength

- short term (during installation)

- long term (installed)

[N] [N]

2700 1300

2700 1300

2700 1300 Compressive stress/crush

(Attenuation increase fully reversible)

Impact resistance (E=3Nm, r= 300mm)

(Attenuation increase fully reversible)

Outer PE jacket

nom thickness 1.5mm

Dielectric strength member

Interstices fully filled

Corrugated steel tape

Inner PE sheath nom thickness 1.0mm Dielectric central member

Outer diameter approx.: 14.3 mm Weight approx.: 195kg/km

DIRECT BURIED CABLE

Buffer tube,filled with 6 single-mode fibres.