8 PC Power Supply Cable Color Codes (Purpose Explained)

Every PC uses a Power supply unit that provides adequate wattage to each hardware component. If you look at the cables present in the PSU, there will be color coding, but it doesn’t tell what it means. Since many users are unaware of these color codes, we are providing you with detailed information on the purpose of these color codes and what they represent.

PC Power Supply Cable Color Codes

List of PC Power Supply Cable Color Codes

PC power supply cables typically follow standard color codes to provide users with visual identification of the nature of their connectivity. Also, these color codes help users identify and connect the cables correctly, reducing the risk of improper connections and potential damage to components. Here are the color codes used in PC power supply cables and their purpose.

Black or Gray Colored Cable

The black is typically used for ground (GND) connections. Ground wires provide a path for electrical current to return to the power supply, completing the circuit and preventing electrical hazards.

Black wires are typically used for ground connections because black is a universally recognized color for grounding purposes in electrical wiring. It serves as a visual indicator for users to identify and connect the ground wires correctly.

The ground wire’s purpose is to protect against electrical faults and provide a safe path for excess electrical current to dissipate. It helps prevent electrical shock by diverting potentially dangerous currents away from sensitive components into the ground.

In a PC power supply unit, the ground connections are crucial for maintaining the electrical balance within the system. They ensure that all components, including the motherboard, processor, and peripherals, are protected from the leaking voltage. A common reference point helps maintain stability and prevents voltage fluctuations that could damage sensitive hardware components of the PC.

The use of black wires for ground connections also helps distinguish them from other power wires that carry different voltages. Overall, the black color code for ground wires in PC power supply cables is an important part of ensuring electrical safety, maintaining system stability, and facilitating proper installation and maintenance procedures.

Yellow Colored Cable

Yellow is commonly used for +12V DC connections. These wires provide the main power supply voltage for most components in a computer, including the motherboard, CPU, and graphics card.

Yellow wire carry +12V power from the PSU to the respective components. The +12V voltage rail is crucial for supplying power to demanding components in a computer system, particularly the CPU and graphics card, which often require substantial power for their operation. The +12V power is used to run motors, drive fans, and provide power to other high-performance peripherals.

Additionally, the high power demand of components connected to the +12V rail necessitates the use of appropriately sized wires to handle the current flow without overheating. Therefore, the use of yellow as the color code aids in ensuring proper gauge selection and cable quality for efficient power transmission and safety.

Overall, the color yellow in PC power supply cables signifies the +12V DC connections, which are vital for powering critical components in a computer system.

Red Colored Cable

Red is usually associated with +5V DC connections. The +5V voltage rail powers various components, such as USB ports, some motherboard components, and certain peripherals.

The +5V voltage rail is an important power supply line that delivers a stable and regulated 5 volts of direct current to the connected components. It plays a vital role in powering devices that require a +5V power source, such as USB devices, fans, LEDs, and certain integrated circuits.

Red is a commonly recognized color for power, and its use in PC power supply cables for +5V connections aligns with this convention. It serves as a visual aid to differentiate the +5V cables from other voltage lines within the system.

Proper connection of the red +5V cables ensures that the connected components receive the required power to operate correctly. It contributes to the overall functionality and performance of the computer system.

Orange Colored Cable

Orange is commonly used for +3.3V DC connections. The +3.3V voltage rail supplies power to specific components, such as memory modules (RAM) and certain motherboard components.

The +3.3V voltage rail is particularly important because it provides power to critical components that require a lower voltage than what is supplied by the +5V or +12V rails. In modern computer systems, the +3.3V rail is vital for the proper functioning of DDR memory modules, as well as various integrated circuits and peripherals that operate at lower voltages.

Blue Colored Cable

Blue is used for -12V DC connections. The -12V voltage rail is relatively less used in modern computer systems but can be necessary for certain legacy devices or specialized hardware.

The -12V voltage rail provides a negative voltage supply, which is essential for certain devices which might include older serial ports, some audio equipment, or specific industrial components. The -12V rail is not widely utilized in standard consumer desktops or laptops.

The blue wire’s purpose is to carry the -12V voltage from the power supply to the designated components or connectors. It helps ensure proper functioning and compatibility with devices that rely on this negative voltage supply.

It’s important to note that in newer power supply standards, such as ATX12V 2.3 and later versions, the -12V rail is not mandatory, and the blue wire might be absent. This is due to the reduction in usage of devices that rely on the -12V supply in modern systems.

Therefore, if you have a modern PC power supply, you may not find a blue wire or a -12V connection. However, for older systems or specific hardware requirements, the blue wire serves as a crucial identifier for the -12V voltage rail.

White Colored Cable

White in PC power supply cables are typically used for -5V DC connections. However, it’s important to note that the -5V voltage rail is rarely used in modern PC power supplies and has been discontinued in newer standards. As a result, the presence of white wires in power supply cables has become less common in recent years.

The -5V voltage rail was once utilized to power certain devices and components that required a negative voltage supply. These could include older serial ports, ISA expansion cards, or specialized peripherals.

However, with the advancement of technology and the shift towards more efficient and standardized power requirements, the need for the -5V voltage rail has diminished significantly. Removing the -5V rail from modern power supplies allowed for greater efficiency and cost savings, as well as a reduction in the complexity of the power supply unit itself.

Therefore, it’s important for users to refer to the specific documentation provided by the power supply manufacturer to understand the color codes and functionalities of the cables they are working with, as variations may exist between different models and manufacturers.

Green Colored Cable

The green is specifically reserved for the Power Good (PG) signal. This wire carries a signal from the power supply to the motherboard, indicating that the power supply is operating correctly. The Power Good signal is a crucial aspect of the power supply unit (PSU) that communicates with the motherboard to indicate the stable and reliable delivery of power.

The green wire carries a low-level, continuous signal from the power supply to the motherboard, indicating that the power supply is functioning correctly and within the specified parameters.

When the power supply is turned on, it takes a brief moment to stabilize and provide steady power to the system. During this time, the Power Good signal wire transmits a signal to the motherboard. The motherboard waits for a positive Power Good signal before allowing the system to boot up fully. If the signal is not received or is interrupted, the motherboard will not initiate system operations, preventing potential damage or instability caused by inadequate power.

Purple Colored Cable

Purple wires are often associated with +5VSB (Standby) connections. The +5VSB voltage rail provides a low-power standby voltage even when the computer is turned off.

The +5VSB voltage rails power feature like Wake-on-LAN, which allows the computer to be powered on remotely, and certain USB charging functionality even when the computer is powered off. This enables devices such as smartphones or tablets to be charged through USB ports on the computer, even if it’s not actively running.

The purple wire is used to connect the +5VSB voltage rail from the power supply to the motherboard. This connection allows the motherboard to receive signals to power on the system when the appropriate input is detected, such as pressing the power button or receiving a wake-up signal.

The +5VSB voltage rail also provides a small amount of power to keep some components active in standby mode. This includes maintaining the system’s real-time clock and powering certain circuitry responsible for functions like remote control capabilities.

Therefore, the purple color code for +5VSB wires in PC power supply cables is crucial for providing standby power to enable various features and functionalities in a computer system, even when the system is turned off. It facilitates functions such as remote power-on, USB charging, and maintenance of essential components in standby mode.

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These are the color codes used in PC power supply cables and with this information, you can easily identify which cable to connect appropriately. The specifications of each color code are standard, and the purpose mentioned here is also commonly used. If you find any variations, you can look into the manufacturer’s manual for detailed information.

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