Cable Gland Assembly: An ultimate guide on the working of cable glands

The high-tech world uses electrical and electronic devices in almost all areas of our life, and every application uses cable assemblies. People working with these cables must be careful while terminating cables, especially in harsh and dangerous environmental conditions. One such very reliable component for sealing cable ends is the cable gland. This blog post discusses cable gland assembly techniques.

What are cable glands?

You can use cable glands as mechanical cable entry devices in combination with cables and wiring for:

• Automation systems like data, telecoms, power, and lighting
• Electrical, control, and instrumentation

The cable glands mainly work as terminating and sealing tools; you can call them to cord grips, cable fitting, or cable connectors.

The function of cable glands

In addition to the protection of electrical equipment and enclosures, cable glands have multiple other functions, including:

Holding force

Cable glands also ensure mechanical cable pull-out resistance on the cable.

Earth Continuity

In armored cables, cable glands are present as a metallic structure. In such systems, you can test the cable glands to identify if there is sufficient peak short circuit fault current.

Environmental protection

Cable glands seal the cable sheath’s outer side, protecting from moisture and dust to the enclosure or the instrument.

Additional environmental sealing

At the entry point of the cable, cable glands ensure the correct rating of ingress protection with the help of different accessories.

Additional sealing

It also offers high ingress protection (if required) at the cable area near the enclosure.

Weatherproof

Cable glands come with an IP68 waterproof function which means you can use them to make watertight exit points in severe or adverse environmental enclosures or through bulkheads. The cable glands help compress a seal into a round cable so that there is no ingression of water or other particles which may damage electronic devices.

For example,

You must drill a hole to pass a cable through a watertight enclosure. As a result, it will no longer be watertight. To make it watertight again, you can use a cable gland to create a waterproof seal around the cable passing through the enclosure.

For cable from 3.5mm to 8 mm in diameter, an IP68 waterproof function works well.

Caption: electrical cable with connectors

Components of cable glands

You can determine the different parts of cable glands based on the type of cable glands. There are two types of cable glands:

Single compression cable gland

The single compression cable gland does not have a cone and cone ring. Instead, it only has a neoprene rubber seal to provide mechanical support to the gland when attached to the cable. The other parts of the single compression cable gland are:

• Gland body
• Gland body nut
• Flat washer
• Check nut
• Rubber washer
• Rubber seal
• Neoprene

You can use these cable glands for lightly armored cables, and the cable has some scope of getting damaged through corrosion or moisture with these cable glands.

Double compression cable gland

This cable gland differs from the above as it has a double sealing feature. Its cone ring and cone offer mechanical resistance to the cable, and you can use them where large armored cables and wires are coming out and getting into the board.

These cable glands work as weatherproof or flameproof cable glands. The different components of the double compression cable glands are:

• Check nut
• Cone ring
• Cone
• Neoprene rubber seal
• Gland body
• Gland body nut

Caption: cable connectors

Specifications of cable glands

You need to consider several specifications before you pick one for you. Here are some.

Material

Cable glands are available in various materials. 

• Stainless steel cable glands have high-pressure ratings and provide corrosion and chemical resistance.
• There are cable glands made of steel.
• You can also opt for PVC or polyvinyl chloride cable glands featuring smooth surfaces, non-toxic features, and good flexibility. As PVC is passive, manufacturers use some food and chemical processing grades.
• Apart from this, there are PTFE (Polytetrafluoroethylene) cable glands. These glands are highly resistant to chemicals and have a low friction constant.
• There are nylon glands that are tough and exhibit a high-pressure rating.
• Some others are made from brass, offering low magnetic permeability, good conductivity, corrosion resistance, cold flexibility, high-temperature ductility, and good bearing properties.
• Some cable glands comprise aluminum which is a bluish-white metal. It is an easily malleable and ductile element and shows excellent thermal conductivity.
• The metal also provides high reflectivity and resistance to oxidation.

Performance

The performance of the cable gland type is also essential which depends on the:

• Complete ambient operating temperature
• The pressure that a cable gland can bear without leakage
• Size selection that cable glands can accommodate
• Number of elements accommodated by assembly
• Size of thread or mounting feature

Installation of cable gland

When installing cable glands, you must follow local regulations and codes of practice. Carry out cable gland installation only if you are an experienced person. You must have the skill and knowledge needed for gland installation and take training. Here is a guide to ensure cable glands’ safe and reliable installation.

Installation tools

While you carry out cable gland installation, you need to choose some cable gland tools that ensure the safe installation of cable glands without damaging any material or equipment. 

PPE: Wear this to avoid personal injury while terminating or handling cables.

Digital Measuring Device: Check and record the cable size to verify it for each cable termination.

Spanners: You can use them to install the product correctly.

Armor forming tool: It helps prepare armor wires for the termination in the body of the cable gland.

Hacksaw: It helps to cut armor wires.

Outer seal tightening guide: You can correct the cable gland size.

Safety knife: It helps cut only the armor wires without damaging the bedding and insulation layer beneath them.

Electrical scissors: It helps remove excess cable braid. Ensure that you pick a sharp one so there is a clean cut without any snagging.

Cable Gland Assembly: Installation standards

The installation codes and standards for cable glands and accessories are:

1.IEC & EN 62444: for cable glands used in electrical installations

2. IEC 60079: explosive environment (Parts 0, 1, 7, 11, 14, 15, 17, 31, etc.)

3. IEC 61892: installations for mobile and fixed offshore units

4. IEC 60092: for electrical installations made in ships

NFPA 70/National electric code, Article 500 (for class or divisions), Article 505 for class/zone.

CEC or Canadian electric code, sec 18 for hazardous locations

API recommended practices API RP 14FZ and API RP 14F

NORSOK Standards E-001, Z010, I-001

Cable Gland Assembly: Cable gland installation safety:

During installation, you can ensure safety in many ways, such as:

Ensure that you do not damage entry threads while installing cable glands.

Do not start installing cable glands in live circuits. Similarly, wait to open the glands until you de-energize the circuit.

Different components of cable glands are compatible with each other only if they are from the same manufacturer. Further, installing components from the same manufacturer ensures the safety of the installation.

Cable glands fall under certification protocols, and a manufacturer cannot sell the installed products’ spare parts.

The sealing rings of the cable gland come with cable glands right from the factory. Under no circumstances are sealing rings removed from the cable glands.

Do not expose sealing rings to dirt, chemicals, and other foreign bodies.

Cable Gland Assembly: Installation instruction:

Follow these instructions to install cable glands:

Detach the two components of the cable gland, i.e., the entry point and nut

Now, fix a shroud over an outer cable

The Remove the cable outer sheath and braid to properly manage the cable to fit into the equipment geometry.

Remove the outer sheath 18mm away to reveal the armor

Remove any wrapping or tapes to reveal the inner sheath if required

Now, secure the cable entry component into the equipment

Allow the cable to pass through the entry item and space the braid around the cone in an even fashion.

Prevent contact between the cone and the armor and screw the nut tightly to engage the armor.

With this, you complete the installation.

Cable Gland Assembly: Check the performance

After the installation, you must ensure the safety of the cable gland.

Sealing performance: Check the sealing ring’s suitability, functional performance, and reliability. The things that can affect the cable glands’ performance include material choice, sealing design, and valid and effective testing program. Different tests include pull-out resistance tests, thermal endurance, ingress protection, and cable anchorage.

Armor clamping: Loose armor clamping can also result in improper cable gland installation. Using the right armor cone and clamping ring ensures that you create the proper termination that secures the armor wires during the crimping process.

Earth Continuity: If you do not clamp the armor cables correctly, it will affect the potential equalization adversely. With the right armor clamping method, you can create a low-impedance termination that does not undergo self-loosening. Instead, it enables reliable earth passage.

Conclusion

The cable gland is a crucial component for cable assemblies and wiring harnesses. If you need help buying or installing cable glands, contact Cloom. We manufacture a wide range of cable assemblies and deal with all the related components, and our team has extensive knowledge about the cables used in different applications.