What is a Cable Gland? A Guide to Cable Entry and Identification

A cable gland, sometimes called a cable connector, cable fitting, cord grip, or strain relief, is a mechanical device that attaches to the end of an electrical cable to secure it to a piece of equipment. These components are used on cables with diameters typically ranging from 1mm to 75mm.

The cable gland serves multiple purposes: it can provide strain relief, connect to the metallic sheath or armour of a cable, and create a sealed entry point that maintains the enclosure's ingress protection rating.

Beyond simply holding a cable in place, cable glands perform several critical cable management roles. They provide earthing, grounding, bonding, insulation, and strain relief. They can seal cables passing through bulkheads or gland plates, repel external contaminants such as dirt, dust, or fluid, and in certain applications, contain electrical sparks or flames.

The main function of a cable gland is to act as a sealing device that ensures the protection of enclosures on electrical equipment. This protection encompasses several aspects critical to safe and reliable installations.

Where higher ingress protection is required, cable glands provide additional sealing capabilities. This is particularly important in outdoor installations, industrial environments, or areas where equipment may be exposed to washdown procedures or harsh weather conditions.

Different materials offer different levels of performance depending on the application, environment, and cable type. The two primary categories are metal and plastic cable glands.

Metal Cable Glands

Metal cable glands have wide-ranging use across many applications, particularly in areas that demand high chemical and mechanical stability. Common materials include brass, stainless steel, and aluminium. They are commonly used in the chemical industry, heavy industrial settings, and applications requiring EMC (electromagnetic compatibility) shielding.

Plastic Cable Glands

Plastic or nylon cable glands offer a cost-effective solution for less demanding environments. They are lightweight, corrosion-resistant, and suitable for indoor applications or areas where metal glands are not required.

For armoured cables, additional factors must be considered, including the diameter of the lead covering and inner bedding, the cable armour's short circuit rating, and the size and type of armour braid.

Cable gland earth tags are metallic components installed between the cable gland and equipment to provide an earth bond connection. This earthing function is essential for safety, ensuring that all exposed conductive parts are at the same potential to prevent shock hazards.

Earth tags serve as the path for fault current to flow safely to ground in the event of a fault condition. For installations using steel wire armoured (SWA) cables, the earth tag connects the cable's metallic armour to the equipment's earthing system.

Cable Gland Earth Tag Installation

Proper cable gland earth tag installation requires careful attention to ensure electrical continuity and compliance with relevant standards. The tag is typically positioned as a slip-on component between the gland body and the equipment face, with an earth conductor secured to the tag's lug.

The location of earth tags, whether inside or outside the enclosure, can affect the IP rating of the installation. Always consult the gland manufacturer's guidance for specific installation requirements.

While cable glands secure and protect cables at entry points, proper cable identification at these locations is equally important for safe and efficient installations. Clear cable labelling enables maintenance personnel to quickly identify circuits, troubleshoot issues, and work safely on equipment.

Cable identification near gland entry points should include information such as the cable reference number, source and destination, and any relevant circuit information. Labels should be positioned where they remain visible after installation and can withstand the environmental conditions present.

Label Types for Gland Applications

Different label types suit different applications at cable gland locations. For harsh industrial environments where cables may be exposed to chemicals, oils, UV light, or extreme temperatures, Fox-Flo® tie-on cable labels offer exceptional durability. Made from Low Smoke Zero Halogen (LSZH) material, these labels maintain legibility throughout the equipment's lifespan while meeting fire safety requirements.

For general commercial applications, Fox-in-a-Box® enables you to print a wide variety of cable labels using one software, one printer, and one ribbon. This flexibility means you can produce the right label type for each application, whether tie-on tags for cables near gland plates or wrap-around labels for cable runs.

Both cable gland selection and cable labelling should align with relevant industry standards and site-specific requirements. For data and telecommunications infrastructure, standards such as ANSI/TIA-606 provide guidelines for cable identification and documentation.

In environments such as rail, offshore, or public buildings, Low Smoke Zero Halogen (LSZH) materials may be required for both cables and their labels. This ensures that in the event of fire, materials do not emit harmful halogen gases or excessive smoke that could impair evacuation or damage equipment.

Documentation and Records

Maintaining accurate records of cable installations, including gland types, cable identifications, and test results, supports ongoing maintenance and future modifications. Software solutions such as Labacus Innovator® can help generate consistent labelling while maintaining project documentation.

What size cable gland do I need?

Cable gland size is determined by the outer diameter of the cable and the thread size of the entry hole in the equipment. Manufacturers provide sizing charts that match cable diameters to appropriate gland sizes. Always measure the actual cable diameter rather than relying on nominal specifications.

How do I label cables at gland entry points?

Position labels close to the gland but ensure they remain visible and accessible after installation. Tie-on labels such as Fox-Flo® work well for this application as they can be secured independently of the cable's surface condition. For more guidance, see our step-by-step guide to labelling terminated wires.

Do I need an earth tag for every cable gland?

Earth tags are required for armoured cables where the armour provides the circuit protective conductor (CPC). For unarmoured cables or installations with separate earth conductors, earth tags may not be necessary. Always follow the electrical design and relevant standards for your installation.

What IP rating should my cable gland have?

The cable gland should maintain or exceed the IP rating of the enclosure it serves. For outdoor or wash-down areas, IP66 or IP68 glands are commonly specified. The sealing performance depends on correct installation and using the appropriate gland for your cable diameter.