Have you ever heard of lay cable? This article explains everything you need to know about it.
What is Lay Cable?
Underground cables are used in electricity distribution for low and middle-voltage systems.
They are surrounded by a protective jacket and are laid in compact bundles about 1 meter deep.
Cables with a voltage higher than 110 kV are laid deeper, at 2-3 meters deep. That’s because they produce more heat and need more distance between conductors.
Underground cables also produce electric and magnetic fields, but the electric fields are mostly shielded by the jacket and the soil.
However, the magnetic fields are not shielded and only decrease with distance.
There is little experience in using underground cables in extra high-frequency systems.
Gas Insulated Lines (GIL) are used in high-voltage systems, they are mostly used in areas with restricted spaces or in cases of sensitive environmental conditions.
GIL systems produce very weak magnetic fields and no electric fields in their surroundings.
Methods of Laying Underground Cable
There are several methods of laying underground cable.
1. Direct Laying
Direct laying is a simple and cheap method of laying underground cables where a trench is dug, the cable is laid on a bed of fine sand.
Fine sand used to prevent moisture, and then covered with another layer of sand and bricks to protect it from mechanical injury.
The advantages of this method include being simple and cost-effective, providing good conditions for dissipating heat, and being safe and clean.
Disadvantages of this method include being difficult to extend or make changes to and high maintenance cost. Besides, it’s also difficulty to locate faults, and not being suitable for congested areas where excavation is difficult.
2. The Draw-In System
Picture from electricaleasy.com
The Draw-in System is another method of laying underground cables. Where that are conduit or ducts made of materials like glazed stone, cast iron, or concrete are laid in the ground with manholes at regular intervals.
Cables are then pulled into position from these manholes.
Some of the advantages of this method include being able to make repairs or changes without opening the ground, simpler joints, and stronger mechanical protection.
The downsides include high initial cost, reduced current carrying capacity due to the close grouping of cables, and less favourable conditions for dissipating heat.
This method is suitable for congested areas or short-length cable routes where excavation is difficult.
3. The Solid System
Picture from electricalpowerenergy.co
Lastly, the solid system is a method of laying underground cables where the cable is laid in open pipes or troughs dug out in the ground along the cable route.
The troughing is made of materials like cast iron, stoneware, asphalt or treated wood.
After the cable is laid, the troughing is filled with a bituminous or asphaltic compound and covered over.
Cables laid in this manner are usually plain lead covered because the troughing provides good mechanical protection.
However, this method is more expensive than the direct laying method, requires skilled labor, and favorable weather conditions.
Additionally, due to poor heat dissipation facilities, the current carrying capacity of the cable is reduced.
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Benefits of Lay Cable
There are several benefits of lay cable.
1. Aesthetics
Burying utility lines can enhance the appearance of outdoor spaces by minimizing the visibility of wires, which can be seen as unsightly.
This can also facilitate projects like expanding sidewalks and planting trees without the obstruction of power lines.
2. Safety and Community Health
Undergrounding power lines can eliminate fire hazards, accidents, safety risks, and power outages caused by fallen lines.
This also decreases the potential of health issues related to electromagnetic radiation and increases road safety by reducing the likelihood of cars colliding with poles.
3. Reduced Maintenance
Underground cables provide more dependable service to citizens by eliminating power outages caused by weather conditions.
This means that incidents such as falling branches, strong winds, and heavy snow will not cause the same level of disruptions or damages as overhead lines.
4. Economic Development
Experts in urban revitalization agree that investing in the visual enhancement of commercial areas is one of the most effective ways to attract new businesses and stimulate economic growth.
By focusing on the cleanliness and attractiveness of retail and commercial spaces, communities can prosper.
Setia Urus Harta Sdn Bhd is a reputable company that provides a wide range of building maintenance services to its clients in Malaysia.
They specialize in the installation and maintenance of underground cable, also known as lay cable, which is an important aspect of building maintenance.
Their team of experienced professionals is equipped with the necessary knowledge and skills. It’s to provide high-quality services, ensuring that their clients’ buildings are safe, efficient, and comfortable.
Discover the benefits of lay cable for your community with Setia Urus Harta.