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Cable Gland Size Calculation: Ultimate Guide

Author    |    hongxiang_admin    |    March 19, 2024

In the field of electrical and electronic engineering, cable glands play a vital role in providing safe and reliable connections to cables. Choosing the correct size cable gland is critical to ensuring proper installation and protection against environmental factors such as dust, moisture and vibration.

However, determining the correct size can be a complex task as it requires consideration of various factors such as cable diameter, material and cable gland specifications.

In this ultimate guide, we’ll explore the factors to consider and the steps to follow when accurately sizing your cable gland, helping you make an informed decision and ensure a safe and efficient cable installation.

Understanding Cable Glands

A cable gland, also known as a cable connector or cable fitting, is a device designed to secure and seal cables entering electrical equipment or enclosures. They protect against environmental factors such as dust, water, and other contaminants while maintaining the integrity of the cable.

Importance of Correct Cable Gland Sizing

Cable glands are used to secure and protect cables entering electrical equipment or enclosures. They provide a seal to prevent dust, water, or other contaminants from entering the unit. Here are the main reasons why it is important to correctly size cable glands:

Proper cable support

Cable glands should provide sufficient support to prevent tension on the cable. If the gland is too small, it may not secure the cable securely, resulting in damage or disconnection of the cable. On the other hand, a gland that is too large may not provide enough support, causing the cable to become loose or misaligned.

Effective sealing

The main purpose of a cable gland is to create a watertight seal around the cable entry point, protecting electrical installations from moisture, dust or other particles. Using a gland that is too small may result in an improper seal, leaving the installation vulnerable to potential damage or failure. Properly sized glands ensure a tight, reliable seal, minimizing the risk of contamination.

Comply with standards and regulations

Electrical safety standards and regulations often require correct sizing of cable glands. These standards specify minimum size requirements based on cable diameter and type. Complying with these standards ensures that the installation meets the necessary safety requirements and minimizes the risk of electrical hazards such as short circuits or electric shock.

Easy to install and maintain

Using the correct size cable gland makes the installation process easier and more efficient. It ensures that cables are installed correctly, reducing the effort and time required for installation. Likewise, when maintenance or repair is required, using a properly sized gland provides quicker access to the cable, making troubleshooting or replacing components simpler and more convenient.

Easy to install and maintain

Steps to Calculate the Actual Size of a Cable Gland

To calculate the actual size of a cable gland, follow these steps:

1. Measure the outer diameter (OD) of the cable you will be using the gland with. This is the widest point of the cable.
2. Determine the nominal size of the cable gland. This is typically based on the outer diameter (OD) of the cable.
3. Look up the nominal size of the cable gland in a cable gland sizing chart. These charts provide the specific dimensions for each nominal size.
4. Calculate the actual size of the cable gland by referring to the chart. The chart will give you the appropriate dimensions for the thread size, thread length, and overall size of the gland based on the nominal size.
5. Double-check the actual size by measuring the cable gland using a calliper or other measuring tool. Ensure that the dimensions match those indicated in the sizing chart.


It is important to ensure that the cable gland size matches the cable size to ensure a proper and secure fit.

How to check you have the correct cable gland size?

To check that the cable gland is the correct size, follow these steps:

Measuring the diameter of the cable – Use a caliper or tape measure to measure the outer diameter of the cable. Make sure to measure the widest point of the cable.

Compare cable diameter to a gland size chart – Most cable gland manufacturers provide a gland size chart that lists recommended gland sizes for various diameter cables. Match the measured cable diameter to the corresponding gland size on the chart.

Verify compatibility – Check the specifications of the cable gland to make sure it is suitable for the specific type of cable you are using. Some cable glands are designed for specific cable materials, such as PVC or metal-sheathed cables.

Consider Cable Gland Thread Size – In addition to the cable diameter, you will also want to make sure that the cable gland’s thread size matches the thread size of the entry hole or device you are connecting to. Check the specifications of cable glands and equipment to ensure compatibility.

Benefits of Using High-Quality Cable Glands

Using high-quality cable glands provides several benefits, including:

How to check you have the correct cable gland size

Enhanced protection

Increased safety

High-quality cable glands provide a tight seal around the cable entry points, protecting the internal components from moisture, dust, dirt, and other environmental factors. This helps to prevent damage to the cables and ensures optimal performance and longevity of the connected equipment. Cable glands that meet international standards for safety, such as IP68 or IP69K ratings, offer improved protection against water ingress and dust penetration. This significantly reduces the risk of electrical shorts, shocks, or fires, making them ideal for applications in harsh or hazardous environments.

Reliable performance

Easy installation

High-quality cable glands are designed to withstand various mechanical stresses, including vibration, pulling, or bending of the cables. This ensures that the connections remain secure and intact, minimizing the chances of signal loss or disruptions. Cable glands with user-friendly designs make installation quick and hassle-free. They often feature simple push-fit or screw-in mechanisms, allowing for efficient and tool-free setup. Additionally, high-quality cable glands are compatible with a wide range of cable types and sizes, ensuring versatility in various applications.

Cost savings

Aesthetically pleasing

While high-quality cable glands may have a higher initial cost compared to lower-grade alternatives, they offer longer-lasting performance. This means fewer replacements or repairs are required, resulting in lower maintenance costs in the long run. High-quality cable glands often come in sleek and visually appealing designs. This can be beneficial in applications where cable management and aesthetics are important, such as in offices, homes, or commercial spaces.


Cable gland sizing is a critical aspect of any electrical installation. Choosing the right size is critical to ensuring proper functionality, safety and compliance with industry standards. If you have any other questions, please feel free to contact us.