Is the optical cable suitable for indoor or outdoor use?

Optical cables, as the "blood vessels" of fiber optic networks, their quality and applicability directly affect the transmission efficiency and stability of the entire network. So, how should we choose optical cables? In fact, optical cables can be clearly classified into indoor optical cables and outdoor optical cables based on different usage environments. These two types of optical cables have significant differences in multiple aspects such as structural design, sheath materials, and weather resistance. Many people may wonder, then, which type of optical cable supports indoor use or outdoor use? This article will take you through a comprehensive and in-depth understanding of this issue.

Whether the optical cable is suitable for indoor or outdoor use depends on its structure and materials.

1. Indoor optical cable: 

This type of optical cable has a series of unique features. Its outer sheath is mostly made of flame-retardant, low-smoke, and halogen-free (LSZH) materials. The selection of such materials is not accidental but based on the special requirements of indoor environments. In relatively enclosed spaces such as those within buildings, once a fire occurs, ordinary materials may release a large amount of toxic smoke, posing a serious threat to the lives and safety of people. However, flame-retardant, low-smoke, and halogen-free materials can effectively prevent the spread of fire when exposed to fire and produce very little smoke, providing precious time and a relatively safe environment for personnel evacuation and rescue.

From a structural perspective, indoor optical cables are usually designed to be relatively lightweight. Such a design makes it more convenient during the wiring process. In complex wiring environments within buildings, frequent operations such as bending and conduit insertion are required. The lightweight structure can reduce the difficulty and workload of construction and improve the efficiency of wiring. However, it should be noted that indoor optical cables are usually not waterproof or resistant to ultraviolet rays. This is because indoor environments are relatively stable and do not need to deal with harsh natural conditions like outdoor environments. But precisely for this reason, indoor optical cables are not suitable for use in outdoor environments. Otherwise, they are prone to damage due to external environmental influences.

The typical application scenarios of indoor optical cables are very extensive. In buildings, they are widely used for connecting various devices, such as from distribution frames to terminal devices, ensuring smooth information transmission within the building. In equipment rooms, numerous servers, switches, and other devices also need to be efficiently connected through indoor optical cables to achieve rapid data exchange and processing. In addition, in indoor fiber-to-the-home (FTTH) wiring, indoor optical cables also play an important role, introducing optical fiber signals to thousands of households, providing people with high-speed and stable network services. Common indoor optical cable models include GJFJV, GJXH, GJPFJ, etc. These models have their own advantages in different specific application scenarios and can meet diverse needs.

2. Outdoor Optical Cables:

The outer sheath of outdoor optical cables is generally made of PE/HDPE materials. These materials possess waterproof, UV-resistant, and tensile-resistant properties. Waterproof performance is essential for outdoor optical cables because in outdoor environments, rainwater may erode the cables, exposing the optical fibers and causing damage. The UV-resistant feature can effectively resist the long-term exposure to ultraviolet rays from the sun, preventing the outer sheath of the cables from aging and cracking, thereby extending the service life of the cables. The tensile resistance feature enables outdoor optical cables to withstand certain external traction forces, such as during overhead laying, where they can resist the effects of wind and other natural forces, ensuring the integrity of the cables.

In addition to the characteristics of the outer sheath, outdoor optical cables usually also have reinforcing structures such as steel wires/aramid/casing layers added internally. These reinforcing structures are like the "skeleton" of the optical cables, providing stronger mechanical strength and tensile resistance for the cables. In the face of some complex outdoor environments, such as strong winds and severe weather conditions like snow and ice, these reinforcing structures can ensure that the optical cables do not break or deform due to external forces, guaranteeing the stability of fiber optic transmission.

It is precisely because of these excellent characteristics that outdoor optical cables can adapt to harsh environments. Whether it is exposed to wind and sun or subjected to rain and snow corrosion, they can maintain a good working condition. Their typical application scenarios include urban pipeline communication. In the underground pipelines of cities, outdoor optical cables can stably transmit signals and provide strong support for the communication network of the city; overhead optical cables are like information bridges spanning the sky in cities, transmitting signals to every corner; in rural broadband coverage, outdoor optical cables play an even more important role. It can cross vast fields and complex terrains and bring high-speed network services to rural areas. Besides, in data center parks and base station interconnections, outdoor optical cables are also indispensable. They connect various important nodes, ensuring efficient data transmission and interaction. Common outdoor optical cable models include GYXTW, GYTS, GYTA, GYTA53, etc. These models have their own applicability and advantages in different outdoor environments.

Three key points for judging whether to choose indoor or outdoor optical cables

1. Installation environment. If the optical cables are installed in buildings or equipment rooms, then in such cases, indoor optical cables can generally be used. Because the environments in buildings and equipment rooms are relatively stable and mild, the main requirements for protecting the optical cables are fire prevention and ease of wiring. The characteristics of indoor optical cables can exactly meet these needs. However, if they are used in buildings between each other or in outdoor environments, then outdoor optical cables must be selected. Because in buildings between each other or in outdoor environments, the optical cables will face various complex natural environments and external force factors, such as wind, sun exposure, rain erosion, temperature changes, etc. Only outdoor optical cables can withstand these harsh conditions and ensure the stability and reliability of fiber optic transmission.

2. Wiring method. When using the method of laying optical cables in pipes/bridges, either outdoor optical cables or enhanced indoor optical cables can be selected. Pipes and bridges can provide some protection for the optical cables to reduce the direct impact of the external environment on the optical cables. Therefore, in this case, both the more protective outdoor optical cables and the enhanced indoor optical cables with certain protective capabilities can be chosen. However, if direct burial/floating laying is required, then outdoor optical cables must be selected, and even armored optical cables may be needed in some special environments. When directly buried, the optical cables need to withstand the pressure of the soil, the erosion of groundwater, and possible external force damage caused by ground construction; when laid overhead, the optical cables need to withstand the tests of wind, rain, sun exposure, and natural forces such as ice and snow. Only outdoor optical cables, especially armored optical cables, can meet these high requirements for wiring methods and ensure the safety and stable operation of the optical cables.

3. Fireproof/Flame-retardant requirements. In some special places, such as fire escape routes and elevator shafts, since the consequences will be very serious if a fire occurs in these places, fireproof indoor optical cables (LSZH) should be selected. Fireproof indoor optical cables can effectively prevent the spread of fire when a fire occurs, reduce the harm to personnel and equipment, and also ensure that the optical cables can still maintain certain transmission functions for a period of time after a fire, providing support for rescue and emergency communication.

It is particularly necessary to emphasize here that ordinary indoor optical cables must never be used in outdoor environments. Because ordinary indoor optical cables do not possess the protective properties required for outdoor conditions such as waterproofing and UV resistance. Once they are used outdoors, they are prone to be eroded by moisture and rain, as well as accelerated aging due to UV radiation, which can lead to damage to the optical cables and affect the normal operation of the fiber optic network.

Furthermore, some "universal optical cables" possess certain protective capabilities and can be used in both short-distance indoor and outdoor environments. These universal optical cables take into account the requirements of both indoor and outdoor settings to a certain extent. However, in practical applications, it is still necessary to make careful choices based on specific usage scenarios and requirements to ensure the reliability and stability of the network.