A guide to cord grips

The purpose of strain-relief cord grips

Cord grips, also called cable glands, perform a number of essential roles in cable management. Designed to attach and secure the end of an electric cable and the device it’s connected to, cord grips provide earthing, grounding, insulation, bonding and strain relief. They can also be used to seal cables which pass through bulkheads of gland plates.

They are often located in hazardous or harsh environments where they need to contain electrical sparks or flames, or repel outside contaminants such as dust, dirt and fluids, such as the challenges facing an outdoor utility cabinet. In addition to this, their job is to stop cables becoming twisted or pulled to ensure a secure connection and continual performance.

In our guide, we'll cover:

• How to choose cord grips
• The purpose of armoring in cables
• Types of cord grips
• Cord Grip Materials
• Installing cord grips
• Cord Grip Considerations

https://iec.ch/homepageHow to choose cord grips

You have a world of choices before you and unfortunately, there is no one-size-fits-all option. But it does mean that you can custom select a cord grip based on your parameters. And to do that, you first need to consider a range of environmental and application factors.

The role of the environment

It doesn’t matter whether you’re working in aerospace, industrial, marine, power and utility, telecommunications or any other key industry. What’s important is identifying the core application environment of your cord grip. Questions to ask yourself:

• Are you using it indoors or outdoors?
• Will it be situated in a safe industrial zone or a hazardous or explosive environment?
• What’s the temperature and is it constant?
• Is the surrounding area damp or dusty?
• Are there any gases or corrosive materials nearby?

Your answers will help determine the cord grip specs and whether it requires a special protective plating or coating.

The purpose of armoring in cables

Different cables demand different types of cord grips. For example, the requirements for an armored cable, also called steel wired armored (SWA) are different to those of unarmored cables. Armored, or SWA, cables are used on exterior walls or underground.

Type	Characteristics	Application
Armored	Extra layer of protection to prevent damage This may be a single wire armor, braided armor, pliable wire armor or double steel tape armor	Areas where exposed to threat of mechanical damage
Unarmored	More basic than armored Can have no seal, or have a single outer seal or a double outer seal	Fixed installations not exposed to risk of mechanical damage

 

Does armored cable need conduit?

Typically, no. They’re armored for protection. You should use conduit for unarmored cable, however.

IP-rated cable glands

Cord grips are designed with safety in mind, so they come with an IP rating to ensure you know what you’re getting. The Ingress Protection Marking (IP) rates the glands depending on their design and efficiency throughout different tasks. These ratings often go up to IP68 and IP69K. It’s important to check that any devices placed in explosive atmospheres comply with national or international codes of practice. You can learn more about the ratings with IP codes and what they mean.

Types of cord grips

Below are examples of cord grips:

Cable gland size guide

• Cable diameter
• Construction size
• Cable material

For armored cables, you also need to consider:

• The diameter of the inner bedding
• The diameter of the lead covering
• The short circuit fault rating of the cable armor
• The type and size of the armor braid

Cord Grip Materials

Cable gland materials perform differently depending on the application, environment and cable type.

Metal cord grips are used in a range of applications, including the chemical industry, technology and areas with high demands on special mechanical and chemical stability. The pros are durability over time, even in wet conditions, and its rigid stability.

Plastic cord grips have a wide cable range due to their claw and seal design, which makes them extremely adaptable to various applications. The pros are resistance to salt water, grease and weak acids, just to name a few.

At a glance:

Material	Common applications	Characteristics
Metal cord grips	Medical equipment Controlling devices Measuring devices In machinery	Corrosion resistance Electrical and thermal conductivity
Nylon cord grips	Telecommunications Instrumentation Data cables Electrical power	Ideal for use on flexible cables High strain relief Can bear the highest IP rating (IP68) Available in colors for color coding cables

 

How to install a cable gland

Cable gland installation depends on the type of gland you’re using, but the basics are the same. You’ll need to follow the relevant codes of practice, your local regulations and the manufacturer’s cable-gland-installation instructions. Installation should only be carried out by a skilled person with experience and knowledge of cable glands.

Note: Take care not to damage loose entry wires.

Getting started

Step 1: Turn off all electrical equipment and disconnect any live wires

Step 2: Make sure your cord grip is compatible with your cables

Step 3: Keep cord grips clear of solvents, chemical substances, and dirt during installation

Installing cord grips

Step 1: Open the cable gland and remove the nut.

Step 2: Peel back the outer sheath of the cable to the same length of the cord grip itself. If there’s an inner metal armor, expose it.

Step 3: Insert the right end of the gland into the cable.

Step 4: Lay the peeled sheath or armor evenly around the gland.

Step 5: Apply the nut, taking care to tighten with a spanner to secure the gland in place.

Extra protection features

Your application or environment may demand the cord grip to possess a specific quality, above and beyond its basic function. That’s where you may consider one the following special features:

• Fire-stop cord grip which can withstand fire propagation through a barrier
• Explosion-proof cord grips
• EMI and RFI shielding and associated grounding features to minimize or eliminate electromagnetic or radio frequency interference
• Romex connections to specifically deal romex cables
• Wire mesh for additional strain relief
• Liquid tight cord grips to protect against penetrating oils and waters

Cord Grip Considerations

There are a few important considerations that fall outside of the categories above. So before you choose a cable gland, also ask yourself:

• Is the wire hole diameter large enough to house all the cables in the system?
• Is the cable diameter sufficient?
• Is the pressure rating high enough for your application needs?
• Is the mounting hold diameter large enough for my cord grip?
• Is the depth and size of the grip thread metric or PG?
• Is there a requirement for stopper plugs to close off any unused cable entries?

Download free CADs and try before you buy

Free CADs are available for most solutions, which you can download. You can also request free samples to ensure the solution you’ve chosen is exactly what you need. You might also find these guides helpful:

• Ultimate guide to cable management
• Quick guide: industrial components for outdoor cabinets
• Quick guide: the small HVAC components for your HVAC design
• Guide to cable strain relief and protection

 

If you’re not quite sure which cord grip will work best for your application, our experts are always happy to advise you, whether it’s with standard cable gland sizes, suitable outdoor cable glands or anything else that you need. We also offer plastic grommets, so we can help you with that too. Whatever your requirements, you can depend on fast despatch. Request your free samples or download free CADs now.

Questions?

Email us at sales@essentracomponents.com or speak to one of our experts for further information on the ideal solution for your application 800-847-0486.