What Is A Cable Gland?
A cable gland, also sometimes called a cable connector or strain relief device is defined as a mechanism that allows the attachment and securing of the end of a cable to an electrical device. Additionally, they provide a seal for the protection of cabled devices, ensure the safety of the cabled device from the environment (e.g., water and dust), and provide strain relief to the cable. cable glands are an essential part of electrical systems in many different industries, from electrical service equipment to heavy industrial equipment.
Common Cable Gland Types
There are many types of cabling glanding, and these types are divided into categories based on their construction, material composition, and the environment in which they will be used, so there are many types of cable glands that are used for many different applications. The most common types of cable glands can be listed as follows:
1. Metal Cable Glands
Metal Cable Glands include brass, stainless steel, or aluminum and are known for their durability, high tensile strength and provides resistance to extreme harsh environments. By their very designs, these types of cable glands provide additional mechanical protection in heavy-duty industrial use.
2. Non-Metallic (Plastic) Cable Glands
Constructed of either nylon or high-quality polycarbonate plastics, these types of cable glands have several advantages over metal. Metal Cable Glands are generally heavier than their non-metallic equivalents, and they also tend to rust and corrode easily. Non-metallic cable glands can be used for general-purpose applications in the absence of extreme temperatures or mechanical stress, such as in telecommunications or consumer electronic devices.
3. Explosion-Proof (EX) Cable Glands
Ex Cable Glands are designed specifically to be fitted into or connected to equipment that is in a classified area, such as the oil and gas or chemical industries where flammable vapours, gases, or dust may be present. They are manufactured to comply with rigorous industry safety standards, and are thus safe to use in hazardous locations.
4. Waterproof Cable Glands
Cable glands that are water resistant, use enhanced sealing materials (typically rubber or silicone) to protect the cables from water damage. They are most often installed in marine applications as well as in outdoor lighting fixtures.
5. EMC Cable Glands
Cable glands which are manufactured to protect sensitive electrical devices from electromagnetic interference (EMI) caused by equipment that produces electromagnetic interference (i.e., electrical appliances). These types of cable glands are generally located in locations where sensitive electrical devices are being used or are located near to other devices that produce electromagnetic interference.
6. Multi-Entry Cable Glands
Cable glands that provide Multi-entry – this refers to an application or installation with numerous cables passing through one entry point. Cable glands are advantageous for providing compact, space-saving design solutions for installations where access to the interior of an enclosure (for example, control systems) is limited in size (cable entry) and number of cable entries required.
Components of a Cable Gland
Typically, the main components of a cable gland consist of:
- Body: The main structure (usually metal or plastic) holds the cable gland together. It provides mechanical support.
- Seal: The rubber or silicone seals keep the cable gland watertight, dustproof, and protects against dirt and water from entering through the opening of the cable near where it connects with the enclosure.
- Locknut: A threaded nut attaches the cable gland to the enclosure (inside of the opening).
- Clamping Mechanism: Provides strain relief and holds the cable securely in place so it cannot be torn from the installation.
Choosing the Right Type of Cable Gland
The correct selection of a cable gland depends on several factors, including:
- The type and size (armored or unarmored) of cable being inserted into the cable gland.
- The environment that the cable gland will operate in (temperature extremes, humidity, proximity to chemicals, water, etc.).
- The intended use for the cable (hazardous or standard).
- The ingress protection (IP) rating required for the application (for example, an IP68-rated cable gland would be used for wet locations).
When selecting the proper type of cable gland for a given application it is strongly recommended to use a cable gland specification chart to make sure the selected product meets the project requirements.
Common Applications of Cable Glands
Cable glands are widely used in various industries, including the manufacturing, automotive, renewable energy, and construction industries. They provide essential services in terms of ensuring safe, reliable, uninterrupted operation of electrical systems (wind turbine electrical connections) as well as providing security for data cabling used on construction sites. Cable glands help improve operational efficiency while reducing system downtime and improving safety to personnel and equipment.
Frequently Asked Questions About Cable Glands
1. What does a cable gland consist of?
Electrical cable glands are made up of four main components: main body (typically metal or plastic), seals (rubber or silicone), threaded locking nut, and – occasionally – clamping insert to provide strain relief (optional). Each of these components should be chosen to suit the intended operating environment.
2. What are the advantages/disadvantages of using metallic vs. non-metallic cable glands?
Metallic cable glands generally provide superior strength, durability, and resistance to extreme operating conditions making them ideal for tough industrial environments. While non-metallic cable glands are lighter-weight, corrosion-resistant, and cost-effective in comparison to metallic cable glands, they are more suitable for common applications in less demanding operating environments.
3. What is an IP rating and how does it apply to cable glands?
Ingress Protection (IP) ratings provide an indication of how well a given cable gland provides protection from dust as well as moisture. An IP68-rated cable gland would provide 100% dust and moisture protection making it ideally suited for harsh industrial environments.
4. Am I able to use the wrong type of cable gland?
Using the wrong type of cable gland could pose a risk to personal safety, damage to the environment, cable failure, and/or damage to the equipment to which the cable is connected. When selecting a cable gland for an application, always refer to the installation requirements and/or consult an electrical professional for assistance.
Cable glands are critical components of electrical and mechanical cable connections used in a wide variety of industrial applications. From metallic vs. non-metallic and specialized/ex-proof & waterproof cable glands, selecting the proper type of cable gland is essential for safe operation and performance of the system. Understanding your application requirements and considering environmental conditions as well as adhering to electrical codes will help ensure a successful installation of long-lasting, reliable, and safe cables.