Pushable Fiber Patch Cord

A pushable fiber patch cord (also known as pushable fiber cable, blown fiber, or micro-duct fiber) is a special type of optical fiber cable designed to be installed into empty, pre-placed micro-ducts using compressed air.

Think of it like this:
The micro-duct is the "highway" or "tube."
The pushable fiber cord is the "car" that drives on that highway.
The compressed air is the "engine" that pushes the car.
It is a key technology in the Fiber-to-the-Home (FTTH) and 5G network deployments.

How It Works: The Two-Stage Installation Process

This system separates the cable infrastructure from the fiber itself, which is its biggest advantage.
Stage 1: Install the Micro-Duct Pathway
Empty, flexible plastic tubes (micro-ducts) are installed throughout a building, along streets, or in conduits. These tubes can be bundled together into larger ducts. This stage can be done during initial construction, without needing to decide exactly where every fiber will go.
Stage 2: "Blow" or "Push" the Fiber Cord
 
When a customer orders a service or a connection is needed, the pushable fiber cord is installed.
One end of the cord is fed into the micro-duct.
A specialized blowing machine injects compressed air into the duct. This air flow creates a drag force that, combined with a pushing force at the input, propels the cable over long distances with very low friction. The process is fast and can cover over 1,000 meters in a single run.

Key Characteristics of the Cable

The cable itself is engineered for this unique installation method:
Smooth, Hard Outer Sheath: Has a low-friction, hard coating (often using materials like HFFR - Halogen Free Flame Retardant) to slide easily through the micro-ducts.
Small Diameter: Typically very thin, with common diameters being 3mm, 4mm, or 6mm.
Lightweight: Designed to be as light as possible for the air to push it effectively.
Robust: Despite being thin, it contains strength members (like aramid yarn) to withstand the pushing force and tensile stress during installation.
 

Advantages and Benefits

Future-Proof & Scalable: You can install a network of empty micro-ducts once. Then, fibers can be added on-demand as needed. There's no need to overbuild with unused fibers, saving initial costs.
Fast and Flexible Deployment: Connecting a new customer or site is very quick—just blow a fiber to their location without digging or major construction.
Lower Initial Investment: Capital expenditure is reduced because you don't pay for all the fiber optics upfront.
Reduced Installation Friction: The blowing technique causes significantly less stress on the fiber compared to traditional pulling, leading to better long-term reliability and performance.
Longer Installation Distances: This method can install fiber over much longer continuous distances than conventional cable pulling.

Comparison with Traditional Fiber Patch Cords

Feature	Pushable / Blown Fiber Cord	Traditional Fiber Patch Cord
Installation Method	"Blown" or pushed with air into micro-ducts	Pulled manually through conduits
Infrastructure	Requires pre-installed micro-ducts	Requires pre-installed conduits or trays
Flexibility	High. Fibers can be easily added or replaced later.	Low. Cables are fixed; changing requires re-pulling.
Initial Cost	Lower for infrastructure	Higher (pay for all fiber upfront)
Deployment Speed	Very fast for on-demand connections	Slower, as all cables are installed at once
Typical Use Case	FTTH, 5G Fronthaul, large campus networks	Data Centers, LAN/MAN wiring, fixed connections

In short, a pushable fiber patch cord is a revolutionary installation-specific cable that enables a highly flexible, cost-effective, and future-proof method of deploying fiber optic networks. It decouples the infrastructure investment from the fiber deployment, allowing network operators to react quickly to market demands.
 
How many types of the pushable fiber patch cord? Here is a breakdown of the common types:

1. By Fiber Count

This is the most straightforward way to categorize them, defining how many individual optical fibers are inside the cable.
Single-Fiber Pushable Cable:
 
Structure: Contains one optical fiber.
Diameter: Very thin, typically 3mm or 4mm.
Use Case: Ideal for FTTH (Fiber-to-the-Home) drop connections, connecting from a street termination point directly to a single subscriber's home. It's the most common type for final customer installation.
Illustration: A single "lane" highway for one car.
Multi-Fiber Pushable Cable:
Structure: Contains multiple fibers, commonly 2, 4, 6, 8, 12, or even 24 fibers.
Diameter: Thicker, typically 5mm, 6mm, or larger.
Use Case: Used for feeding multi-dwelling units (apartments, office buildings) or for blowing from the central office to a neighborhood distribution point. This allows one cable to serve multiple end-users.
Illustration: A multi-lane highway for many cars.

2. By Fiber Type

The type of optical fiber inside determines the cable's data transmission capabilities.
Single-Mode (OS2):
Characteristics: Has a very small core (8-10µm). Designed for long-distance, high-bandwidth transmission with low signal loss.
Use Case: The standard for FTTH, telecommunications backbones, and long-haul networks. This is the most common type found in pushable cables.
Multimode (OM1/OM2/OM3/OM4):
Characteristics: Has a larger core (50µm or 62.5µm). Designed for shorter distances, typically within buildings or campuses.
Use Case: Less common in outdoor blown fiber applications, but can be used for short-distance interconnects in large enterprise campuses or data centers using a blown fiber system.

3. By Jacket Material

The jacket's material determines where the cable can be safely installed.
Low-Smoke Zero-Halogen (LSZH / ZHFR):
Characteristics: Made from a special compound that does not emit toxic or corrosive fumes when exposed to fire.
Use Case: Mandatory for indoor installations, such as inside office buildings, apartments, and public spaces. It is the standard for safety.
Polyethylene (PE):
Characteristics: Excellent weather, moisture, and UV resistance.
Use Case: Designed for outdoor environments, such as direct burial in the ground or installation in conduits.
Armored Pushable Cable:
Characteristics: Features a metal tape or corrugated steel armor underneath the outer jacket for extra mechanical protection against rodents, crushing, and digging.
Use Case: Used in direct-buried applications where extra protection is required, especially in areas with high rodent activity.

4.Specialized Types

Figure-8 / Self-Supporting Pushable Cable:

Characteristics: The pushable fiber cable is attached to a steel messenger wire in a "figure-8" shape during manufacturing.

Use Case: Allows for aerial installation on telephone poles without the need for a separate lashing wire. The messenger wire provides the strength for the aerial span.

Summary Table of Common Types

Category	Type	Common Diameter	Typical Application
Fiber Count	Single-Fiber	3mm, 4mm	FTTH drop (Home connection)
	Multi-Fiber (e.g., 2-12F)	5mm, 6mm	FTTB (Building feed)
Fiber Type	Single-Mode (OS2)	Various	Most Common: FTTH, Long-distance
	Multimode (OM3/OM4)	Various	Short-distance, Campus links
Jacket	LSZH (Indoor)	Various	Inside buildings, apartments
	PE (Outdoor)	Various	Buried conduits, Aerial ducts
	Armored	Various	Direct burial (high-risk areas)

 

In practical terms, the most common pushable fiber cord you will encounter is a single-fiber, single-mode cable with a 3mm LSZH jacket, used by technicians to connect a single family home to the fiber network. The specific type chosen for a project depends entirely on the network design and environmental requirements.