Low-voltage and underground cables – Features & applications

1.1 What are low-voltage cables

Low-voltage cables are a type of electrical cable specifically designed to transmit low-voltage power, typically below 1000V. It is commonly used in residential electrical systems, local area networks (LAN), data transmission, and telecommunications systems.

Low-voltage cables are usually installed using a structured cabling system, which optimizes construction, maintenance, and management of wiring networks. Proper installation is essential to avoid signal interference, data loss, or electrical hazards.

As a critical component in connectivity, communication, and device control, low-voltage cables are foundational in smart home systems, office buildings, automated factories, and various industrial applications.

1.2 Structure of low-voltage cables

The typical structure of low-voltage cables includes the following components: conductor, insulation layer, filler, armor, shielding layer, and outer sheath.

• Conductor: Usually made of copper or aluminum. Copper-conductor cables offer high conductivity, suitable for high-performance and high-reliability applications. Aluminum cores are lighter but typically larger, making them ideal for applications such as wind power.
• Insulation: Usually made of PVC or XLPE material.
• Filler: Typically plastic, used to fill gaps between conductor cores, maintaining the cable’s shape and enhancing mechanical strength.
• Outer sheath: Generally made of PVC.

Some low-voltage cables are equipped with an armor layer, which protects the cable from mechanical impacts such as compression, tension, or vibration in harsh industrial environments. Armor is typically made of aluminum or galvanized steel.

1.3 Applications of low-voltage cables

Low-voltage power cables are essential solutions for modern power distribution systems. Due to their stable conductivity and ease of installation, they are widely used in both residential and industrial sectors.

• In residential electrical systems, low-voltage cables are used to transmit electricity from substations to end-use areas such as homes, office buildings, shopping centers, hotels, service facilities, hospitals, and schools.
• In industrial applications, low-voltage power cables play a crucial role in supplying power to machines and motors, running production lines, and connecting automated and control systems.

Thanks to their flexibility and durability, low-voltage cables are considered an optimal solution for systems requiring safety, efficiency, and cost-effectiveness.

2.1 What are underground low-voltage cables?

Underground low-voltage cables, or buried low-voltage cables, are electrical cables installed below ground. These cables play an essential role in modern electrical systems, providing safe and efficient power transmission over long distances.

Compared to overhead lines that are vulnerable to weather conditions, underground cables are protected by the earth, resulting in more stable and reliable power systems with fewer faults.

2.2 Characteristics of underground low-voltage cables

An underground cable typically consists of one or more conductor cores, insulated and encased in a protective sheath to resist external factors. It must meet the following criteria:

• Conductors must be tinned copper or high-conductivity aluminum.
• The cross-sectional area must be large enough to handle the current without overheating and keep voltage drop within acceptable limits.
• The insulation must be thick enough to ensure safety and reliability at the designed voltage.
• A suitable mechanical protection layer must be included to withstand installation and operational impacts.
• Cable materials must offer long-term chemical and physical stability, resisting degradation over time.

Common installation methods include:

* Direct burial

• Description: Cables are buried directly in the ground without protective conduits.
• Advantages: Quick installation, low cost.
• Disadvantages: Vulnerable to moisture and mechanical impact if soil is unstable.
• Application: Areas with low mechanical impact and soft soil.

* Ducts and conduits

• Description: Cable is inserted into HDPE, PVC, or metal conduits before burial.
• Advantages: Protects against water, insects, chemicals, and mechanical impact. Facilitates cable replacement or upgrades without excavation.
• Application: Urban areas, industrial zones with high infrastructure density.

* Cable trenches

• Description: Specialized trenches lined with sand, concrete, or warning markers for added protection.
• Advantages: Maximum safety in high-risk or high-traffic areas.
• Application: Medium- and high-voltage systems, critical infrastructure zones.

3.2 Security cables

HELUKABEL product range includes:

• (N)HXH-FE 180/E 30 (52700)
• (N)HXH-FE 180/E 90 (53180)
• (N)HXCH-FE 180/E 90 (59028)
• (N)HXCH-FE 180/E 30 (52900)

3.3 Fire alarm cables

HELUKABEL product range includes:

• JE-H(St)H Bd FE 180/E30-E90 (34081)
• J-H(St)H Bd Fire Alarm Cable (34116)
• JE-H(St)H Bd Fire Alarm Cable FE 180/E90 (34091)
• JE-H(St)H Bd Fire Alarm Cable FE 180/E30 (34157)

These cables feature static screens, effectively blocking electromagnetic interference. They are ideal for permanent installation in critical fire-safety areas to protect people and assets during a fire - commonly used in industrial zones, manufacturing facilities, and public buildings.