Cord grips, also known as strain reliefs, cable support grips, cable glands, or cord connectors, relieve stress on cables, prevent cable damage and failure, and allow electrical cables to pass into enclosures or equipment. These devices also offer strain relief, vibration protection, and protection against liquid and dust while stopping the cable from being withdrawn from its installation.
When choosing an cord grip, you must consider the material, size, and installation design factors. Although most cable support grips have similar features, the quality and execution of these features can differ. In this post, you will learn about the factors to consider when choosing a cord grip. So read on.
Size
Choosing the appropriate cable gland size depends on the cable’s outside diameter (OD), the threaded opening or knockout size, or whether you need single or multiple cable terminations. Cable OD is vital because it determines the size of the hole in the enclosure or machine and helps choose a cable gland that fits tightly during installation.
The cable’s OD determines the cord connector size for single cable termination. However, all cables or conduits must be fed through a single hole for multiple terminations, so the cord grip size should fit all cables’ OD. The size of the knockout or threaded opening is another factor to consider. If the size is unknown, choosing the smallest cable gland that fits the cable’s OD is advisable.
Construction Material
There are several materials to choose from, including diecast zinc, aluminum, nylon, steel, valox, and stainless steel. While diecast zinc is suitable for residential and commercial applications, it only fits industrial use because of its soft and imprecise threads and inferior tensile strength.
- Aluminum is the most commonly used material in industrial applications thanks to its excellent durability, machineability, and performance.
- Nylon offers excellent corrosion resistance, is lightweight, and has durability. It would help if you used it in damp environments and corrosive applications.
- Steel has better tensile strength than aluminum and is typically zinc-chromium plated for enhanced rust resistance and better appearance.
- Valox offers superior corrosion resistance and is suitable for use in FDA-mandated washdown environments. However, it is the most expensive and only available in limited sizes.
- Stainless steel has exceptional tensile strength and the highest durability. These features make it ideal for severely corrosive environments like those filled with acids, chemicals, and salt water. However, it is only available in limited sizes.
Style and Attachment
Manufacturers typically manufacture two types of cord grips: straight and 90°, and choosing between them depends on various factors such as cable orientation, available space, and how the equipment should look.
Wire mesh attachments are also available. Their necessity depends on whether the cable or conduit needs protection from pull-out or if the application involves high-traffic areas, high-flex or excessive vibration, overhead suspension, or dropped cables. Wire mesh grips provide extra strength and security to protect the electrical termination
The Type of Thread
When choosing a cable gland for an application with a threaded opening, it’s essential to consider the thread type. The three most commonly used thread types are NPT, Pg, and ISO Metric. It’s critical to determine the thread type before selecting a cord connector, and you can do this by checking the spec sheet that came with the enclosure or equipment or by contacting the manufacturer. Once you determine the thread type, you can choose a cord connector with similar threads as your enclosure.
