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Earth cables play a critical role in electrical circuits, serving as essential components that connect appliances to the ground. Their primary function is to safeguard individuals from electrical shocks by absorbing excess electrons and channelling them into the ground. Through this, earth cables provide effective protection against electrical shocks from current leakages. Without integrating earth cables, an individual can be exposed to electrical shocks, ultimately damaging their central nervous system.

Simply put, earth cables are necessary because they are protective conductors that help prevent electrical shocks and fire. It is often easy to identify these cables because they usually come with recognisable characteristics or features. Read on to learn more about earth cables, specifically the sizes, thickness, and colours they ordinarily come with.

Size of Earth Cables

The appropriate size of an earth cable is determined by its application. Temperature, material, length, elements, and fault current all affect the size of the conductor. The type of installation also has a bearing on what an earth cable’s size should be. When selecting an earth conductor, IEEE-80 recommends taking into consideration the following factors:

  • Being conductible to contribute minimally to regional voltage differences.
  • Having the ability to endure fusing and mechanical degradation. This should take place even in worst-case scenarios of the duration and size of a fault.
  • Having a high degree of mechanical toughness and dependability.
  • Having the ability to continuously operate even when subjected to corrosion or physical harm.

Generally, the least earth cable for a moderate household electrical circuit is 1.5 square millimetres in diameter. This size of an earth cable also aids in shielding electrical equipment against electrical shock. The gauge of the earth cable likewise serves as a protection for the hidden wirings within the PVC pipes. On the other hand, for greater electrical circuit capacities, like in the operation of an induction motor with 100 horsepower, a single core cable with a size of 35 square millimetres is ideal.

Thickness of Earth Cables

Electrical earth cables are generally thicker than neutral and live wires. This is because earth cables come with a larger cross-section and a lower resistance, which enable more current to flow through them in case a short circuit occurs. If an electrical failure happens, the current flow then becomes higher than normal. Therefore, it is necessary for earth cables to be thicker so that they can manage higher currents with low resistance.

Moreover, the fault current—which is more or less 50 times the rated current—passes through the earth cable. Hence, a thicker diameter cable is more suitable for evacuating fault current. This also makes third sockets in houses have greater diameters than ph-neutral ones. The earthing pin likewise tends to be thicker in a three-pin plug. However, it is important to keep in mind that a thicker earth pin or cable provides no absolute immunity to electrical shocks. As such, there is still a possibility of receiving an electrical shock.

Colours of Earth Cables

Back in 2006, earth cables were commonly found in green, red, and black. However, the industry has evolved, and today, the designated colours for these cables are green and yellow.

If you still have older earth cables, it is essential to upgrade to the modern green and yellow versions. The shift to green and yellow as the chosen colours for earth cables is rooted in their practicality—these colours align with the common occurrence of green or yellow soil ground. As a result, they are considered ideal for cable grounding purposes.


Earth cables offer an effective preventive measure against various electric mishaps, including electrical shocks. With their capability, earth cables can save not just the cost of repairing or buying new appliances but can also ultimately save lives. Luckily, identifying earth cables that are apt for an electrical system is relatively easy since they usually come with distinct sizes, thicknesses, and colours.

For the safest and highest-quality earth cables in Singapore, Cable Source is a supplier you can trust. Our commitment to excellence is evident in our state-of-the-art cables, which cover a wide spectrum, including earth cables, instrumentation cables, marine cables, offshore cables, solar cables, and more. We go the extra mile by offering top-notch drum reeling cables, enhancing both operational efficiency and safety. Explore our website now to discover more about our comprehensive range of products.