What is OSP?

Outside plant in telecommunications refers to all of the physical cablings and supporting infrastructure (such as conduit, cabinets, towers, or poles), as well as any associated hardware, placed between a demarcation point in one switching facility and another switching center or customer premises.

The communications equipment positioned between the main distribution frame (MDF) and a user end equipment might be considered outside plant.  The inside plant is the section of this infrastructure contained within a building, while the outside plant is the portion of this infrastructure connecting buildings or institutions. The demarcation point in a given structure is where these two plants meet.

Outside plant cabling, including copper or fiber, is typically installed as aerial cable between poles, in an underground conduit system, or through direct burial.  Outside plant hardware must be either protected from the elements or built with materials that can withstand exposure to the elements. Outside plant installation commonly requires the construction of considerable physical infrastructure, such as underground vaults.

Outside plant cabling must also be safeguarded from electrical disturbances such as lightning strikes or voltage surges caused by electrical shorts or induction.

OSP Corrosion

Corrosion in outside plant telecommunications network systems is caused by exposure to the impacts of temperature, humidity, electrical power, and contaminants. Corrosion resistance limitations for these network components are determined by the environments to which they are subjected.

Outside plant conditions can be above-ground, underground, buried, or underwater. Telcordia GR-2836, an industry requirements document, defines these environments and specifies corrosion resistance criteria for telecommunications equipment in each. It also offers references to several ASTM standards.

Above-ground

Above-ground plant refers to all telecommunications equipment that is physically placed on or above ground. Enclosures such as huts, cabinets, and pedestals, as well as the equipment mounted within them, are included. Pole-mounted equipment and cases, as well as pole-line gear, are also included.

Above-ground plants can be subjected to high temperatures as well as humidity that varies with the seasons and daily temperature fluctuations. When humidity condenses on the surfaces of outdoor apparatus or equipment, industrial contaminants that make the condensate moisture corrosive can increase the corrosively of the moisture layer. Wind-borne, salt-laden water droplets can settle on exposed components in seacoast settings.

Pedestals and cabinets may be flooded with mud and corrosive salts under extreme weather conditions. Insect secretions might also speed up deterioration. Rodents biting can expose metallic components that are ordinarily shielded by a polymer or paint coating to a corrosive environment.

Underground

Underground plant includes any telecommunications equipment deployed in underground structures such as utility holes, Controlled Environment Vaults (CEVs), and ducts, as well as related hardware. Underground plants can be exposed to waters carrying native soil’s water-soluble salts. Utility holes frequently reveal indications of sulfate-reducing bacteria-caused corrosion of support hardware and bonding ribbons.

Man-made substances, such as industrial effluent, fertilizers, and de-icing salts, can corrode the environment within utility holes and ducts. Protective plastic coatings and cable jackets can degrade quickly as a result of leaking steam pipes and gasoline seeping from underground storage tanks, which are common in many urban areas.

Buried

Telecommunications equipment such as cables, splice closures, bottom sections of pedestals, and grounding systems are examples of a buried plant.  Buried plants are susceptible to the same corrosive environment as underground plants. Furthermore, gopher bites might expose underlying components to corrosion.

Underwater

An underwater plant refers to all telecommunications equipment placed beneath the surface of a body of water.  This covers cables as well as repeaters. Water might be reasonably clean, stagnant, or heavily polluted by industrial waste.

Running Cables Through Conduit

Conduit is frequently utilized in these applications to transport wires and cabling from a centralized place to a number of specific locations or endpoints. However, it is common to find indoor-rated network cable such as Category 6 cable within this conduit.

Water can permeate the conduit if it fractures. If the wires inside the conduit are indoor-rated, we have terrible news: they are not meant to withstand moisture, thus the cables will not function properly. As a result, network delays, damaged cables, and the need to rip up and replace cabling infrastructure and conduit will follow.

Conduit Below Ground

Most customers will not notice that the underground conduit has water in it and is destroying the indoor-rated cabling within until it is too late and network performance issues are evident.

A conduit placed beneath a concrete slab presents issues, in particular, the conduit may be exposed to water leakage due to natural or man-made catastrophes. If an indoor-rated cable is used in the conduit, it may be damaged by water penetration.

Temperature differentials can potentially harm indoor-rated wires put in conduits. When the ground temperature is cold but the air temperature is warm, a differential-pressure setting is produced in which air can be pulled in.

Moisture can accumulate inside the conduit, and if the cables inside are indoor-rated, damage to the cable will occur even if the conduit itself is not affected.  Warmer air often has a higher moisture content. Condensation happens when this warm, wet air meets the cooler temperatures beneath the concrete, resulting in moisture.

Conduit Below Concrete

Conduit in-grade beneath the concrete slab presents a similar issue. After the conduit has been laid, the rocks are put on top, followed by the concrete. Many people take chances and put an indoor-rated cable in conduit, especially in areas where rain is minimal or temperatures are mild. However, severe showers do occur, even in areas where rain is uncommon. Even floods caused by man-made disasters, such as plumbing failures, can let water into the conduit, exposing the indoor-rated cable to outside elements that it is not meant to withstand.

Where OSP Cable Should be Used

You can extend the reach of your cabling systems and business networks. Outside plant (OSP) cable can be used to run infrastructure underground or overhead, allowing you to expand your networks to the outside and reach over a vast area.

OSP cable, with outdoor ratings, distinguishes itself from standard indoor-rated copper in its ability to retain performance in harsh environments.  It is resistant to abrasion and splitting and is meant to endure flooding, moisture, and extreme high and low temperatures.

Typically, OSP cabling connects separate structures. Unlisted OSP cabling must be terminated within 15 meters (50 feet) of its point of entry into the structure, either via a wall or through the flooring, according to the National Fire Protection Association (NFPA).

A listed OSP cable can stretch beyond the 15-m/50-ft limit and can also be utilized within enterprise buildings in other applications where the properties of OSP cabling are extremely beneficial. A listed cable is one that has been approved by Underwriters Laboratories (UL) for particular flammability ratings and is labeled for its intended purpose, which is often CM, CMR, or CMX.

OSP Standards

Not all OSP cables are created equal. Because each kind is intended for a specific application, there are several standards to consider while choosing OSP cabling.

When planning a network that requires OSP cabling, ANSI/TIA-758-B, the Customer-Owned Outside Plant Telecommunications Infrastructure Standard developed by the (TIA) Telecommunications Industry Association, is a useful guideline to follow.

It refers to all necessary standards for harsh-environment cabling, as well as relevant performance standards.  It also defines the minimum requirements for customer-owned OSP telecommunications infrastructure in a campus setting, as well as the cabling, routes, and spaces required to support the cabling, regardless of population type or size.

Selecting an OSP Cable

Consider the following factors when looking for the right OSP cable.

• NEC ratings such as CMR allow the cable run to exceed the NFPA 50-foot maximum transition length and run for considerable distances throughout your structure.
• Performance stability ensures that the cable will continue to perform mechanically and electrically even if it is subjected to potentially damaging forces in the surrounding environment.
• Ultraviolet (UV) resistance keeps the cable’s outer jacket from becoming brittle and/or fading from the sun’s rays.
• The cable will be able to withstand temperature extremes if it has a wide temperature range. Gel filling keeps moisture out of the cable’s core, assuring stable impedance and insertion loss over the life of the product. Gel-filled cables can be tough to work with, so make sure the gel is simple to install, clean, and demands little prep time.
• With smart homes/buildings on the rise, PoE compatibility is suggested for outside cables. OSP cables, which support power and data over a single cable, simplify and speed up installation.