The difference between overhead cables and insulated cables

The main difference between overhead cables and insulated cables in their structure, application scenarios, advantages and disadvantages, and safety.

Structure and application:

Overhead cable is an uninsulate, bare metal conductor, erected in the air, fixed to the tower by an insulator string, and insulated with air. Its disadvantage is that it occupies more land resources.

Insulated cable uses insulating medium to isolate the metal conductor from the outside world and can be laid on the ground or underground. It is suitable for scenes such as urban underground power grids, power station lead-out routes, and internal power supply of factories and mines where cables need to be protected from the external environment.

The structure of insulated cable consists of three parts: conductor, insulation and sheath. Different parts are made of different materials and have different functions.

The core is the channel for conducting current. Commonly used cable core materials are copper or aluminum, which have high conductivity.

The insulation layer can block the influence of high electric field on the conductor on the outside world. Common insulating materials include polyethylene, cross-linked polyethylene, ethylene propylene rubber, etc.

The sheath protects the cable core and insulation layer from external damage, moisture, penetration and corrosion.

Advantages and Disadvantages: ‌

The advantages of overhead cables include low cost, and the disadvantage is that they occupy more land resources and affect the city's appearance. Its safety is better than that of power cables, and the failure rate is also low.

The advantages of insulated cables include that they occupy less land resources and do not affect the city's appearance. The disadvantage is that the cost is higher.

Safety:

In terms of safety, the safety of overhead cable is better than that of power cables, and its failure rate is also lower than that of power cables. Compared with overhead bare lines, overhead cables can greatly reduce various short-circuit faults and have good power supply safety performance.

What are Overhead Cables?

Overhead cable, known as overhead insulated cable, is an overhead conductor equipped with an insulation layer and a protective sheath.
It is a special cable manufactured by a production process similar to cross-linked cable and is a new transmission method between overhead conductors and underground cables.

Overhead cables are single-core, according to their structure can be divided into hard aluminum wire structure, hard drawn copper wire structure, aluminum alloy wire structure, steel or aluminum alloy core support structure, and self-supporting three-core stripline structure.
The core can be hard aluminum or hard copper wire.

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Advantages and Disadvantages of Conductors

Advantages

• Relative immunity to short circuits caused by external forces (wind, fallen branches), unless they abrade the insulation.

• Can stand in close proximity to trees/buildings and will not generate sparks if touched.

• Little to no tree trimming is necessary.

• Simpler installation, as crossbars and insulators are not required.

• Ease of erection and stringing, less labor intensive, fewer construction resources needed.

• More aesthetically appealing.

• Can be installed in a narrower right-of-way.

• At junction poles, insulating bridging wires are needed to connect non-insulated wires on either side.

  ABC can dispense with one of these splices.

• Less risk of a neutral-only break from tree or vehicle damage, increasing safety with TNC-s systems.

• Significantly improved safety for linespersons, particularly when working on live conductors.

• Electricity theft is made harder, and more obvious to detect.

• Less required maintenance and necessary inspections of lines.

• Improved reliability in comparison with both bare conductor overhead systems and underground systems.

  The company is the world’s best Overhead Insulated Cable supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

  Insulated conductors prevent accidental contact and supply can be maintained temporarily in the event of a suspension system collapse.

Cable Disadvantages

• Additional cost for the cable itself.

• Insulation degrades due to sun exposure, though the critical insulation between the wires is somewhat shielded from the sun.

• Shorter spans and more poles due to increased weight.

• This can lead to much longer repair times for installations in hilly areas due to much higher line weights requiring bigger and more specialized equipment to repair.

• Older installations are known to cause fires in areas where falling large trees or branches regularly cause breaks in lines and or in insulation leading to short circuits which can then lead to burning insulation dripping to the ground and starting ground fires.

• Failure modes through punctures, electrical tracking, and erosion.

Disadvantages of Flexible Cable

• High Investment Cost

  As the outer sheath of the mineral cable is composed of seamless copper tubes, the overall copper content is much more than that of ordinary cables.

• The Joints are Susceptible to Moisture
  The insulation layer consists of mineral minerals, joints, and cable ends it is very easy to chemical reaction with the moisture in the air, and generate hydrogen minerals that can conduct electricity.

• Difficult Construction
  Mineral cable hardness and general cable compared to the high distribution box and bending within the bridge molding difficulties.
  

• The Construction Workload is Large
  Mineral cable where the specifications of more than 35mm are single-core cable, such as a 95mm cable, ordinary cable only 4 × 95 + 1 × 50 five conductors in the same outer sheath.

Coaxial Cable Advantages and Disadvantages

For the other most common cable, coaxial cable, the advantages far outweigh the disadvantages.
But it also has disadvantages that cable manufacturers cannot ignore when producing, and that is that coaxial cable is easy to cause a fault in the operation of the whole network down.
Compared to other cables, this is really a very troublesome point.
However, the advantages of coaxial cable, it is not only inexpensive, and easy to wire and install, but also has good resistance to electromagnetic interference, cable capacity of up to 10Mbps, and a long and durable life.

There are good and bad sides to everything, not that it's bad, just because it doesn't fit.

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