Cable glands may not be the most exciting topic in the world, but they’re essential for protecting your electrical cables from water, dust and other contaminants. In this blog, we’ll take a look at the different types of cable glands and how to choose the right one.
Introduction to Cable Glands
A cable gland is an accessory used to fix, terminate and secure the end of an electrical cable passing through a hole in a wall or panel. A cable gland sealing surface must provide a watertight, dustproof seal against the entry of foreign bodies. The installation of a gland on to an electrical cable and into equipment provides essential environmental protection to the internal components of the equipment.
Cable glands are classified according to their intended use, including:
- Indoor applications
- Outdoor applications (including direct burial)
- Glands for armoured cable
- Glands for cores with copper tape screen
Joints between conduits and glands shall be made gas tight and liquid tight.
Types of Cable Glands
Cable glands are essential in ensuring the electrical safety of an installation. It is important to select the correct type of cable gland for the application, taking into account the type of cable, environmental conditions and level of protection required.
There are three main types of cable gland:
- PG (Parallel) gland – for unarmoured cables
- SWA (Short website address) gland – for armoured cables
- ATEX gland – for use in explosive atmospheres
In addition to these three main types, there are also several other specialist types of cable gland available, such as midget glands, locknuts and reducers.
Selection of Cable Glands
The selection of cable glands mainly comes down to 4 key elements:
- The type of cable gland required – is it for indoor or outdoor use, does it need to be waterproof, what protection degree is needed etc.
- The type of cable being used – is it armoured or not, what is the diameter of the outer sheath etc.
- The type of equipment or enclosure being used – is it metal or plastic, what are the entry/exit points etc.
- The environment in which they will be used – will they be subject to mechanical or chemical stresses, what temperatures will they need to withstand etc.
Installation of Cable Glands
Most effective and accepted practice for the installation of cable glands is to torque tighten them by using a calibrated torque wrench and the relevant Nylon Locknut.
The accepted rule when installing threaded metal fittings is “snug plus a quarter turn”. This bears no relationship whatsoever to the recommended tightening torque figures given in this guide, which are there to maintain theclamping force required for each cable gland size, thread size and condition.
To achieve the correct torque, follow these four simple steps: 1. Place the wrench on the gland nut and align it so that when turned, it will tend to screw the gland into the equipment rather than unscrew it. 2. Start the gland nut onto the threads by hand until snug. 3. Torque-tighten using a steady motion until the required value is achieved on your torque wrench dial or scale (refer torelevant table). 4. Finally, double check that your Installation of Cable Glands is secure by trying to unscrew it by hand in an anticlockwise direction
Accessories for Cable Glands
Cable glands provide a sealing and termination point for electrical cables. They are used in a variety of applications, including industrial, marine, and commercial. There are many different types of cable glands available on the market, each designed for specific environments and applications.
Cable glands are available in a variety of materials, including brass, plastic, stainless steel, and aluminum. They are also available in a variety of sizes and styles to accommodate different cable diameters and configurations. Cable glands can be purchased with or without threads, and they can be either fixed or adjustable.
When choosing a cable gland, it is important to consider the environment in which it will be used. For example, stainless steel or aluminum cable glands should be used in corrosive environments. Brass or plastic cable glands should be used in non-corrosive environments.
It is also important to select the appropriate size and style of cable gland for the application. For example, adjustable cable glands should be used when terminating cables with irregular diameters. Fixed cable glands should be used when terminating cables with regular diameters.
Advantages of Cable Glands
Cable glands provide many advantages over other cable termination methods, such as tape, heat shrink tubing, and mastic. When used properly, they provide a watertight seal that prevents moisture from entering the electrical enclosure, which could lead to shorts or shocks. Additionally, they protect the cable’s jacket from abrasion and provide mechanical support to prevent the cable from being pulled out of the enclosure. And finally, they lock the cable in place so that it cannot be easily removed by unauthorized persons.
Disadvantages of Cable Glands
Cable glands have a number of disadvantages, including:
- They can be expensive, especially compared to other electrical connection options.
- They are not as flexible as other options, so they may not be able to accommodate some cable sizes or shapes.
- They require more time and effort to install than other options.
- They are not reusable, so once they are installed, they cannot be removed and reused elsewhere.
Cable glands are essential in many electrical applications. They provide a seal against water and other contaminants, and allow for strain relief so that the cable is not damaged. There are many different types of cable glands, so it is important to choose the right one for the job.
This guide has provided an overview of the most common types of cable glands, their features, and their applications. When selecting a cable gland, be sure to consider the environment in which it will be used, the type of cable being used, and the requirement for strain relief. With this information, you can select the perfect cable gland for your needs.