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USB-C – Length Limitation

By October 13, 2023Knowledge base

The length limits of USB-C cables and connections depend on the version of the USB standard and the specific use case. USB-C cables are designed to be versatile and support various data speeds and power delivery levels. Here are some general guidelines:

USB 2.0

USB 2.0, which is one of the earliest versions of USB-C, supports a maximum cable length of about 5 meters (16.4 feet). However, longer cables may result in signal degradation.

USB 3.0 and 3.1

USB 3.0 and USB 3.1, also known as USB 3.1 Gen 1 and USB 3.1 Gen 2, respectively, support data transfer rates of up to 5 Gbps and 10 Gbps, respectively. These higher data rates are more sensitive to cable length. For USB 3.0 and 3.1 Gen 1, a cable length of up to 3 meters (9.8 feet) is generally recommended. For USB 3.1 Gen 2, the recommended maximum length is about 1 meter (3.3 feet) to maintain the highest data transfer speeds. Longer cables can work but may result in signal degradation.

USB 4

USB 4 is designed to support data transfer speeds of up to 40 Gbps. To achieve these high speeds, the recommended maximum cable length for passive cables is typically 0.8 meters (2.6 feet). However, for longer cable runs, active cables or optical cables can be used to extend the reach while maintaining higher data rates.

USB-C for Power Delivery (USB PD)

USB-C is commonly used for power delivery, allowing you to charge various devices. The length of a USB-C power delivery cable can vary, but it’s important to use quality cables for longer lengths, as voltage drop can become a concern. Standard USB-C charging cables are often 1 to 2 meters (3.3 to 6.6 feet), but longer cables are available.

To carry 100W (watts) of power over a USB-C cable, you typically need to consider the limitations imposed by voltage drop and the cable’s current-carrying capacity. USB Power Delivery (USB PD) is the standard used for delivering higher levels of power, and it can support up to 100W or more. However, the effective cable length for carrying 100W can vary based on factors like cable quality and gauge (thickness of the wires).

As a general guideline:

  1. Shorter cables: For USB-C cables that are relatively short, up to 1 meter (3.3 feet), it’s often possible to reliably deliver 100W of power without significant voltage drop or power loss.
  2. Longer cables: As the cable length increases, voltage drop becomes more of a concern. Longer cables can still carry 100W, but the actual distance over which you can do this will vary based on the cable’s quality and gauge. For high-quality cables with a thicker wire gauge, you may be able to maintain 100W delivery over distances of 2 meters (6.6 feet) or more. However, cheaper or thinner cables might have limitations at shorter distances.

It’s essential to use high-quality USB-C cables with sufficient current-carrying capacity to minimize voltage drop, especially when delivering 100W of power. Thicker cables with larger conductor sizes are better at minimizing voltage drop. Look for cables that are specifically rated for 100W or higher power delivery, and consider cables with higher AWG (American Wire Gauge) ratings, as lower AWG numbers indicate thicker wires and better current-carrying capacity.

Additionally, for longer cable runs, you can consider using active or electronically marked cables, which have built-in signal boosters to help maintain power delivery over extended distances.

Always check the cable’s specifications and the power delivery capabilities of your specific devices to ensure you’re using an appropriate cable for your needs.