What are earthing cables? Advantages and types of earthing cables

1.1 What is earthing?

Earthing is the process of directing leakage current or fault current safely into the ground through a low-resistance conductor. More comprehensively, earthing functions to protect individuals from electric shock hazards.

When you touch the metal casing of an electrical device with damaged insulation, electric current may pass through your body to complete the circuit. In this situation, your body unintentionally becomes a conductive path to earth. If you feel a tingling sensation or mild electric shock when touching an appliance, this indicates potential leakage current and the earthing system should be inspected by a qualified electrician.

In principle, an earthing system provides a safe path for fault current by creating an alternative branch that leads directly to the ground. The neutral conductor is responsible for returning current to the source to complete the circuit under normal operation, while the earthing conductor provides a dedicated safety path for leakage or fault currents, thereby protecting both people and electrical equipment.

1.2 What are the benefits of earthing conductors?

• Enhanced safety: When an electrical system is properly earthed, leakage or fault currents are conducted safely into the ground. Without earthing, in the event of a short circuit or insulation failure, the outer casing of equipment may become energized and pose a serious electric shock risk.
• Improved performance and lifespan: Earthing helps stabilize voltage within the electrical system. By maintaining stable voltage levels, the risk of voltage surges or overvoltage that may damage sensitive equipment is significantly reduced. This is particularly important for sensitive devices such as computers, medical equipment, and telecommunications systems.
• Lightning protection: Lightning strikes can cause severe damage to buildings and electrical systems. A properly designed earthing system provides a low-resistance path that allows lightning current to dissipate safely into the ground.
• Reduction of EMI: Earthing plays an important role in electromagnetic interference control. As more machines and systems are installed within limited spaces, electromagnetic fields generated by different equipment can interfere with each other. Proper grounding helps minimize these disturbances and maintain system stability.
• Compliance with legal and technical Standards: Earthing is not only a safety measure but also a mandatory requirement under electrical regulations in many countries. Electrical systems must comply with established technical and safety standards, in which earthing is a critical component.

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An earthing system consists of multiple interconnected components, each serving a specific function. The main elements include:

• Earthing electrodes: These provide a low-resistance path for leakage or fault current to dissipate into the ground.
• Earthing conductors: These connect exposed metallic parts of electrical equipment to the earthing electrode, preventing the buildup of dangerous voltages.
• Equipotential bonding: Ensures that all metallic parts remain at the same electrical potential, eliminating the risk of spark discharge or dangerous potential differences.
• Earth continuity conductor: Maintains electrical continuity throughout the earthing system, ensuring fault current is reliably transmitted to the grounding point.
• Earthing lead (Main earthing conductor): This is the primary conductor that carries fault current from the electrical system to the earthing electrode.
• Earthing plate: Typically buried deep in the soil, the earthing plate reduces overall grounding resistance and enhances fault current dissipation capability.

Earthing cables are an essential component of any grounding system. They play a critical role in safely transmitting fault currents to the ground and maintaining a stable electrical potential across the entire electrical installation.

• Power plants and renewable energy systems: Earthing conductors provide a safe path for short-circuit currents, leakage currents, and lightning currents to flow into the grounding system. This helps protect generators, transformers, and distribution panels from severe damage and ensures operational reliability.
• Manufacturing plants and industrial zones: In industrial environments, earthing conductors equalize potential between equipment, reduce EMI, and minimize the risk of electrostatic discharge (ESD). In high-tech industries such as electronics and semiconductor manufacturing, proper grounding protects sensitive components from ESD-related damage, improves product quality, and reduces defect rates.
• Construction sites: Earthing conductors are commonly used in temporary grounding systems to ensure safety during the installation and commissioning of medium- and high-voltage electrical systems.
• Residential and commercial building electrical systems: They protect users from electric shock hazards in the event of insulation failure or leakage currents. Earthing conductors also operate in coordination with protective devices such as residual current devices (RCDs/ELCBs) to disconnect the circuit promptly, thereby reducing the risk of fire and equipment damage.
• Data centers and IT infrastructure: Proper grounding ensures stable server operation, reduces electromagnetic interference, and maintains data integrity. Modern systems may also integrate grounding resistance monitoring to optimize operational reliability and maintain compliance with technical standards.

An earthing cable (grounding cable) is a conductive component used to connect an electrical system or equipment directly to the earth. Its primary purpose is to provide a controlled, low-resistance path for excess current, leakage current, or fault current to safely dissipate into the ground.

4.1 Copper earthing cables

Copper earthing cables are the most widely used type due to their superior electrical conductivity and durability. Copper has low resistivity, allowing the cable to carry high fault currents without excessive overheating. These cables are commonly used in industrial plants, substations, data centers, and high-safety electrical installations. Common types of copper grounding cables include:

• Bare copper: The most basic and widely used form in grounding systems. Without an external protective layer, it maximizes copper’s natural conductivity and is often installed directly in the ground or integrated into grounding grids.
• Tinned copper: Features a thin tin coating over the copper core. The tin layer enhances resistance to oxidation and corrosion, especially in humid or chemically aggressive environments.
• Coated copper): Typically insulated with PVC or XLPE. This design improves mechanical strength and protects the conductor from environmental impacts while maintaining high conductivity.

4.2 Aluminum earthing cables

Although aluminum has lower electrical conductivity than copper, it is significantly lighter and more cost-effective. For this reason, aluminum grounding cables are commonly used in large-scale systems where weight optimization and budget efficiency are important considerations.

5.1 Bare copper earthing cables

Bare copper cable is an uninsulated conductive solution widely used in grounding systems and power transmission applications due to its excellent electrical and thermal conductivity. Without an insulation layer, it maximizes current-carrying efficiency and ensures reliable fault current dissipation in earthing networks.

Bare copper conductors are primarily used in:

• Earthing and grounding systems
• Installation on insulator strings for overhead transmission lines
• Lightning protection systems
• Power transmission and distribution infrastructure
• Electrical and electronics industries
• Both DC and AC applications, offering versatility across a wide range of operational requirements

5.3 HELUPOWER® CU-WIRES FLAT BRAIDED BARE / TINNED earthing cables

The HELUPOWER® CU-WIRES FLAT BRAIDED series is manufactured from high-quality annealed copper strands, available in either bare copper or tinned copper versions. The tin-plated option enhances oxidation and corrosion resistance, ensuring long-term durability even in demanding industrial environments. Thanks to its braided flat design, the conductor offers excellent torsion resistance and high flexibility, making it ideal for applications involving continuous movement or mechanical vibration.

With a wide operating temperature range from -20°C to +125°C, the cable maintains stable electrical performance across various environmental conditions. These flat braided earthing conductors are widely used in automotive, railway, energy, and industrial robotics sectors, particularly for mobile or dynamic electrical equipment connections.

5.4 H07V-K / 07V-K green-yellow earthing cables

The H07V-K / 07V-K green-yellow earthing cable is a single-core, finely stranded flexible copper conductor specifically designed for grounding applications in control panels and residential as well as industrial installations. It features heat-resistant PVC insulation and operates at a rated voltage of 450/750V, with a test voltage of 2500V, ensuring high safety standards for both equipment and users.

With its high flexibility, the cable is easy to install in conduits, concealed wall systems, and enclosed electrical installations, making it a reliable solution for compliant and efficient earthing systems.

5.5 HELUPOWER® CU-STRAP FLAT BRAIDED BARE/TINNED earthing strap

The HELUPOWER® CU-STRAP FLAT BRAIDED earthing strap is manufactured from highly flexible flat-braided copper, available in either bare copper or tinned copper versions to enhance oxidation resistance and ensure long-term durability. The product is available in cross-sections ranging from 4 to 120 mm² and in various lengths from 90 to 40000 mm, providing flexibility for a wide range of installation requirements. Thanks to its highly flexible braided structure, it is particularly suitable for confined installation spaces or applications requiring complex bending configurations.

The earthing strap is designed with rounded contact ends, and the contact surface uses seamless crimped cable lugs (without welded joints), ensuring stable electrical conductivity and reduced contact resistance. Its flexible construction makes it ideal for applications involving repeated bending.

The product is widely used in the automotive industry, railway and rail vehicles, robotics, control cabinet manufacturing, energy systems, and control panel components. It is especially suitable for grounding purposes and EMC applications to minimize electromagnetic interference.

Datasheet of HELUPOWER® CU-STRAP FLAT BRAIDED BARE

Datasheet of HELUPOWER® CU-STRAP FLAT BRAIDED TINNED

5.6 Other HELU products for earthing applications

In addition to the products mentioned above, HELU also offers power supply cables for PROFINET devices with a dedicated pink Functional Earth (FE) conductor. This additional FE core ensures stable communication, reduces EMC interference, and enhances overall system reliability.

• HELUCONTROL® PROFINET 24V POWER PVC / HELUCONTROL® PROFINET 24V POWER + FE PVC
• HELUCHAIN® PROFINET 24V POWER PVC / HELUCHAIN® PROFINET 24V POWER + FE PVC

Furthermore, HELU provides two additional grounding cable types: H00V3-D (PVC insulated) and H00S-D (silicone insulated) , designed for portable grounding and short-circuiting applications.

• H00V3-D features a Class 6 extra-flexible copper conductor with PVC insulation. Thanks to its fine-stranded structure, the cable offers excellent flexibility and is suitable for applications requiring frequent handling or movement.
• H00S-D also utilizes a highly flexible Class 6 copper conductor but is insulated with silicone. This insulation enables operation in extreme temperature conditions while maintaining elasticity and high mechanical durability.

The transparent insulation layer protects the conductor from mechanical and chemical influences while allowing easy visual inspection of the core. The products are manufactured according to the harmonized standard PN-EN 61138, ensuring safety and reliability in industrial environments.