A cable gland is a fitting that connects a cable to an electrical source, and also is able to secure the cable so it will not escape. Cable gland units are placed into different categories, depending on whether the gland is used for general industrial work or needs hazard protection against high temperatures or explosions. The cables that fit into the glands are either armored or unarmored and a different type of gland will be required for each variety. The gland itself can be made of metals, such as brass or aluminum, or plastic; each material is useful in a different environment.
When electrical work is done, it is possible to secure a wire to electrical equipment without a cable gland, but this is a bad idea for several reasons. The gland provides sealing power, which ensures that the cable will not slip off during operation. Safety also is provided, because the gland ensures the electrical energy cannot leech from the cable, causing injury to anyone nearby. Glands often provide other safety features, such as grounding the wire or insulating cables, which is why they are often used for cable connections.
There are two major categories for cable glands: industrial and hazardous. An industrial cable gland is a general-use gland that meets general hazard requirements, so it is useful in environments without high temperatures or the risk of explosions. If the environment is hazardous, a hazardous gland is used, because these glands meet the necessary extra requirements. They are extra fortified, so they are resistant to temperatures and outside forces that general glands cannot withstand.
The two types of cables that can fit into a cable gland are categorized as armored or unarmored, and this will play into what gland will be picked for the job. An armored cable will require a gland that can clamp onto the wires and has the ability to terminate the energy from the armored sections. Unarmored wires do not require termination, but the glands need a high degree of protection and retention to keep the wires safe.
Most cable gland units are made from brass, which is thought of as a general material that is corrosion-resistant and conductive. When in the presence of aluminum and moisture at the same time, brass can begin to corrode. Brass is often plated with other metals to make the gland stronger and better against corrosion. Plastic is often used as an alternative to metallic glands.