What is the duct optic fiber cable?

Duct optic fiber cables, also known as conduit or underground optic fiber cables, are designed for installation within protective ducts or conduits, typically buried underground.

Duct fiber optic cables are a key infrastructure component in modern telecommunications, offering secure and reliable pathways for fiber optics within a protected environment.

Their design caters to the needs of dense urban areas and is optimized for long-term performance with minimal maintenance. 

■ Key points of Duct Fiber Optic Cable

Installation

Installed directly in the duct or conduit.

Protection

Offers great protection for the optical fibers due to the protective duct, ensuring the integrity of the cable.

Cable Sheathing

No special requirements for the sheathing. This indicates versatility in the types of environments where the cable can be used.

Construction

Composed of optical fibers in loose tubes, with the tubes stranded around a dielectric FRP (Fiber Reinforced Plastic) or steel wire central strength member

within the inner sheath. This structure provides added strength and protection for the fibers.

Water-Blocking

Some duct fiber cables come with waterblocking materials, enhancing their resistance to moisture.

Use Case

Suitable for underground construction, particularly in metropolitan communications and access networks due to their robustness and protection level.  

■ Most Required Duct Fiber Optic Cable 

Sheaths

Utilizes non-metallic inner/outer sheaths; some are equipped with double-layer sheaths comprising a lowsmoke zero-halogen (LSZH) inner sheath and a

polyethylene (PE) outer sheath. The LSZH sheath helps reduce toxic and corrosive gas emission if exposed to high heat or fire, while the PE sheath offers durability and resistance to environmental factors. 

Design 

Typically designed with 1-36 cores (commonly 12 cores), which can cater to various network sizes and requirements.

Water Protection

The design usually incorporates waterblocking features to protect against moisture ingress, which is critical for maintaining the performance of the cable over time. 

■ Types of the duct optic fiber cables

Uni-tube Armored Cables

Such cables have a single tube for the fibers with the added protection of armoring, APL, or PSP wires, depending on their application. They are lightweight and generally designed for FTTH drop applications (aerial, duct), balancing the cost and being durable.

GJYXFHA/GJYXFHS: Light-armor bow-type drop cable with aluminum tape (APL) or steel tape (PSP), LSZH sheath, for duct/aerial FTTH.

GYXY: Non-armored central tube with steel wires, PE sheath, for aerial/duct use.

GYFXY: FRP rods, uni-tube, PE sheath, lightweight for aerial/duct applications.

GYXTW: PSP-armored central tube with steel wires, PE sheath, for aerial/duct installations.

Stranded Loose-tube Armored Cables

These cables include several loose tubes which are laid around a central strength member, and the outer coat is done with an armoring for added protection, including APL, PSP, and FRP tape. They are intended for installation outdoors in ducts or direct burial, some with added features like anti-rodent/bird properties.

GYFA: APL-armored, stranded loose-tube, PE sheath, for duct/direct burial.

GYFS: PSP-armored, stranded loose-tube, PE sheath, for duct/direct burial.

GYFS Semi-dry: PSP-armored, semi-dry stranded loose-tube, PE sheath, for duct/direct burial with reduced water ingress.

GYFTA: GFRP (FRP) and APL-armored, stranded loose-tube, PE sheath, for duct/direct burial.

GYFTS: GFRP and PSP-armored, stranded loose-tube, PE sheath, for duct/direct burial.

GYTA-1: APL-armored, stranded loose-tube, PE sheath, for duct/direct burial.

GYTS-1: PSP-armored, stranded loose-tube, PE sheath, for duct/direct burial.

GYFTY73-2: FRP tape, double PE sheath, anti-rodent/anti-bird, for aerial/duct use.

Stranded Loose-tube Non-armored Cables

These cables do not use metallic armoring, but rather have non-metallic strength members (FRP or CSM) added for strength. They are proper for such installations either in aerial or duct line where the metal components are required to be limited.

GYFTY: GFRP and CSM, stranded loose-tube, PE sheath, all-dielectric for aerial/duct.

GYTY: Non-armored, stranded loose-tube, PE sheath, for aerial/duct applications.

All-Dielectric Stranded Loose-tube Cables

Completely non-metallic cables (GFRP, glass yarns, or CSM), electrodynamics is excluded from these cables, making them suitable for high-voltage areas or areas that need lightning resistance. Some are additionally improved to ward off the birds/rodents.

GYFY: GFRP and CSM, stranded loose-tube, PE sheath, all-dielectric for aerial/duct.

GYFY63: Glass yarns, double PE sheath, anti-rodent, all-dielectric for aerial/duct.

GYFY Semi-dry: GFRP and CSM, semi-dry stranded loose-tube, PE sheath, all-dielectric for aerial/duct.

■ Analysis and Insights

Uni-tube vs. Stranded: Uni-tube cables, like GJYXFHA and GYXTW, are easier and more lightweight, appropriate for drop or short distances, with stranded loose-tube alternatives like GYFA and GYFTS permitting long-haul usage in harsh environments and higher fiber capacity and durability. 

Armored vs. Non-armored: Armored cables like GYFS and GYTA-1 are designed for areas with mechanical hazards or for installation in bursting soil, whereas non-armored (use of) GYFTY and all-dielectric cables (use of) GYFY prioritize lightweight and non-conductive properties. 

Special Features: GYFTY73-2 and GYFY63 provide anti-rodent and anti-bird properties, while GYFS Semi-dry and GYFY Semi-dry that keep water out using semi-dry technology.

This classification does justice to the scope of the technical applications these cables support in networks from FTTH drop lines to reliable power line communication channels. It is possible to sort out the cables by their types for enhanced clarity on each one. Please Contact Zion communication know if further detailed data is required.