Electrical cable colors

Colors that guarantee safe energy

Electrical cable colors play a fundamental role to maintaining safety and make the work of professionals and users themselves easier. It's not a mere question of aesthetics. Each color has a meaning and a specific purpose that ensures the correct functioning of the electric system, reduces risk of errors, and makes repairs or installations easier.

The color code of cables is somewhat more than a useful practice. It is a universal system established by the International Electrotechnical Commission (IEC) that facilitates the quick identification of the function and phase of a cable, favoring the prevention of incidents and optimizing the efficiency of any electric system.

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What are the elements of an electrical cable?

In order to understand how and why the colors of electrical cables are so important, the first step is to know the elements that make them up. The safety and efficiency of the electricity transmission inside largely depends on them, since each one has a specific function, ensuring the resistance of the cable and allowing its use in different conditions and environments.

The basic structure is essentially made up of:

Conductor. It is the main component and is usually copper or aluminum, due to their high conduction capacity.
Insulation. It surrounds the conductor and is made with zero-conductivity materials, generally plastics such as PVC or polyethylene, which prevent direct contact with other materials and people, preventing short circuits or discharges.
Filler layer. Located between the conductor and isolation, it allows spaces to be filled while homogenizing the cable and giving it a circular appearance
External protection cover. It is designed to protect the cable from external factors such as moisture, abrasion, or chemical products.

Types of electrical cables

Voltage, materials, use... The colors of electrical cables aren't the only thing that differentiates them. There are different classifications based on a multitude of variants which, in practice, exponentially multiply the offer of cables available on the market. However, some of the most common are:

Rigid cables.
They have a solid and unique conductor that is ideal for fixed installations. Their resistance and durability make them suitable for walls and structures where stability is required and movement isn't needed.
Flexible cables.
Formed of multiple copper filaments, these cables allow greater flexibility and are commonly used in applications where the cable must move, such as household appliances and portable equipment.
Shielded cables.
Shielded cables include an extra protective layer made of metal that provides greater protection against electromagnetic interferences and mechanical damage, which makes them ideal for industrial environments.
Coaxial cables.
Used mainly to transmit radiofrequency signals such as on TV and the internet. Their design includes a central conductor surrounded by an insulator, a metal mesh, and a cover, which allows them to be safer and prevent interferences.
Twisted pair cables.
These cables contain pairs of twisted threads that reduce electromagnetic interference and are used in telecommunications and data networks.
High-voltage cables.
Designed to withstand large volumes of voltage in large-scale energy transmission systems, with high-resistance insulations that reduce the risk of electricity losses and leaks.
Low-voltage cables.
Used in low-power domestic and commercial connections, they are suitable for low voltages and provide safety in homes.

Each type of cable has specific applications depending on their flexibility, resistance, and transmission capacity, which facilitates their proper selection in installations of any type.

What do the electrical cable colors mean?

The color code of electrical cables aims to simplify the identification of the function of each cable in any installation. That standardization of electrical color cables also contributes to improving efficiency in installations and reducing the risk of connection errors. The most used are:

Blue cable: This cable, also known as the neutral cable, is tasked with closing the circuit and is essential for balancing the power load.
Brown cable: Known as the phase cable, it is tasked with carrying the active energy from the panel to devices.
Green and yellow cable: The green and yellow combination identifies the earth wire, a key cable for safety.

As well as these three, there are other colors that can be found in more specific or industrial installations:

Black cable: It is often used as an alternative phase cable or in three-phase systems to connect different points of the installation.
Gray cable: In some systems, the gray cable is used as an additional phase or to indicate a second circuit within the same installation.
Red cable: Although less common in modern installations, the red color was traditionally used in some countries to designate a second phase conductor.

What is the neutral cable, phase cable, and earth wire for?

Neutral cable (blue):
Its main function is to close the electric circuit and stabilize the current, allowing the electricity to return to the power supply without creating a risk. Without this cable, the current couldn't return to the source and the system would lose stability. Let's imagine, for example, a light bulb connected to the power grid. In this case, the current would arrive through the phase cable (brown) and would return to the installation through the neutral cable (blue), thus completing the circuit. Without this cable, the light bulb wouldn't turn on because the electricity would have nowhere to return.
Phase cable (brown):
When you plug in a household appliance, such as a toaster, for example, the current flows from the outlet through the phase cable to the resistance of the toaster, generating heat. If this cable isn't well connected, the device may not work or even generate a short circuit. In other words, this is the cable that transports the necessary electricity to power devices. As it is the one that carries the current, it is essential in any electrical installation and its correct connection is basic to minimize risks.
Earth wire (green and yellow):
This cable prevents unwanted currents from accumulating, grounding them and avoiding possible discharges. If a washing machine has a current leak due to a fault in the insulation of the internal wiring, for example, the earth wire redirects that electricity towards the ground instead of it passing to the metal frame of the device. Thus, if someone touches the washing machine, they will not suffer an electric shock. In this way, it protects both the equipment and the users themselves.

Tips to work with electrical cables

Regardless if you know what the blue and brown cable is, what a neutral cable is, or what the color of the phase cable is, the truth is that there are certain basic recommendations that, together with proper training, can facilitate work with these types of components and minimize risks, for example:

Cut electricity in the work area.
Before handling any cable, it is crucial to disconnect the electricity supply from the main switch or the distribution board. This removes the possibility of an unexpected discharge.
Use insulated tools.
Tools designed with insulated materials protect professionals and users from possible discharges or, in other words, increase their safety. Isolated screwdrivers, wire strippers, and pliers are just some examples.
Don't overload connections.
Each circuit has a current limit that it can withstand without overheating. Preventing overloads through the correct distribution of devices in the different circuits reduces the risk of accidents, just like knowing the color code of cables and respecting it.
Use protection devices and measures.
Installing circuit breakers and overload protectors helps to interrupt the electrical flow in case of overcharge or short circuit, protecting both the system and people. Likewise, given the conductive nature of water, it is essential to keep areas free of moisture.

Beyond the colors of cables: our activity

The correct use of electrical cable colors is key to ensure safety. However, beyond the color code, the truth is that wiring is an element that also affects the environmental impact of any installation.

With the aim of joining the commitment to the design of lower-environmental impact products and solutions, at Repsol we have developed our line of sustainable polyolefins for the cable industry. The Repsol Reciclex® range offers biobased and circular LDPE and mLLDPE alternatives with content between 55% and 70% mechanical recycling coming from post-consumer plastic waste as well as two polyolefin ranges: 100% circular coming from chemical recycling and, second-generation bio-circular polyolefins, coming from organic waste, all of them totally certified.

Moreover, we have a full range of polyolefins for cable coating, solutions for natural and black compound coating applications in power and telecommunication cables, LDPE and HDPE grades for cable insulation, and a EVA and EBA range for semiconductor s.

These materials are not only more sustainable from the point of view of their manufacturing, but they are resistant, durable, and minimize power losses, thus also actively contributing to the responsible care for the environment.