Confused about the difference between cable glands and strain relief? You’re not alone. These two components may seem similar at first glance, but each serves a distinct purpose in protecting electrical cables and equipment.
In this blog post, we’ll clarify the primary functions, environmental sealing capabilities, strain relief properties, and typical applications of both cable glands and strain relief.
What Is a Cable Gland
A cable gland, also known as a cable connector, is a device used to attach and secure the end of an electrical cable to a piece of equipment such as a junction box, motor, or control panel. Cable glands provide a secure connection that protects the cable and prevents damage from abrasion, tension, twisting, or compression. They allow the electrical connection to be made in a way that seals the interior of the equipment against external contaminants like dust, dirt, and liquids.
What Is Strain Relief
Strain relief is a technique used to transfer the mechanical stress on an electrical cable away from the electrical termination points and onto the cable’s insulation or outer jacket. The purpose of strain relief is to protect the electrical connections from damage due to cable movement, flexing, or pulling.
There are several methods to provide strain relief. One common way is to use a strain relief gland or cord grip that clamps onto the cable near the point of entry into a piece of equipment. Inside the enclosure, zip ties, clamps, or a knot in the cable can serve as anchor points to provide strain relief and absorb any tension. Adhesive-lined heat shrink tubing is another option that can be used to reinforce the cable insulation at the entry point.
The Difference Between Cable Gland and Strain Relief
Primary Function
The main job of a cable gland is to seal the end of a cable and provide environmental protection at the entry point into an enclosure.
The primary purpose of strain relief is to prevent mechanical forces on the cable from causing damage at the point of electrical termination.
Environmental Sealing
Cable glands provide an environmental seal to prevent ingress of dust, dirt, moisture, or other contaminants into the equipment enclosure.
Most strain relief devices do not offer a seal against the elements.
Strain Relief
While cable glands do provide some anchorage and strain relief capability, this is a secondary function.
Strain relief fittings are expressly designed to secure the cable and absorb mechanical stress.
Application
Cable glands are used at the interface where a cable enters an enclosure such as a junction box, control panel, motor housing, or bulkhead.
Strain relief is used anywhere along the length of a cable where it is subject to movement, bending, or tension, whether inside or outside an enclosure.
When to Use a Cable Gland
- For connecting cables to enclosures or equipment that must be sealed against environmental contamination
- In harsh industrial environments with dust, dirt, oil mist, or wash-down conditions
- In hazardous environments requiring Ex or explosion-proof rated cable entry
- For outdoor installations exposed to weather and moisture
- To maintain the IP rating or NEMA rating of an electrical enclosure
- When frequent disconnection and reconnection of the cable is not required
When to Use Strain Relief
- To protect solder joints, crimped terminals, connectors or splices from mechanical stress
- On cables subject to repeated flexing, vibration, or tension
- At the cable entry point of an enclosure, even when using a cable gland
- On portable equipment, moving machinery, or robotics where cables are constantly moving
- To extend the life of cables and connectors and prevent fatigue failures
- When cables may be subject to being pulled, snagged, or abraded