We all know that an electrical power cord is made up of two or more wires running side by side to form an assembly, in which the ends can connect to two devices, allowing electrical signals to flow from one device to another. However, most of us wonder what that big molded thing at the end of a connector is. That big “thing” is called a strain relief. Sounds pretty self-explanatory, right? Just like its name, a strain relief relieves a cable of stresses and tensions that could break the conductor inside or even the connection between the plug and the cable.
There are different types of strain relief too. The first one always comes molded to the jacket and part of the plug. This type of strain relief is mainly designed to avoid any damage to the conductors and separation of the plug from the cord itself.
Second, we have a type of strain relief called Cable Glands. Cable glands are known as a cable connector or “fitting”. This kind of strain relief often comes in the form of a separate, mechanical cable entry device that is installed over the connector and the cable joint. Cable Glands serve as a sealing device to make sure that the characteristics of the enclosure which the cable enters, can be effectively and securely maintained.
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Depending on the application, cable glands also come at a 90° angled snap “elbow” to minimize wire strain. They help secure the wire connection to the equipment while providing longer life to the cord by preventing it from rubbing against rough or sharp edges where the cord passes through the equipment panel.
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If you work in food processing or water treatment where cords come in contact with liquid, or even applications that are subjected to freezing temperatures, ideal materials of cable grips are stainless steel, nylon, silicone, or nickel-plated brass. These materials are also recommended in situations that subject cords and their connectors to frequent bending and flexing, such as in robotics or automation.
For environments that expose cords to high temperatures such as in welding or cords that are exposed to chemicals, connectors should be made of stainless steel, PVC, or nickel-plated aluminum.