A Guide to Codes & Markings on Cable Products

In today’s world, many consumers are far too busy to be scrutinizing and examining every detail of their products. This is especially true with cables and wires, items that are often plugged into more seemingly important pieces of equipment and used without any consideration for how they are made.

However, if you’ve ever acquired a cable product, like a fiber optic cable, you’ve likely noticed it has some distinguishing features. One of these features is the coding printed alongside the wire. You will likely see a set of numbers, letters or names that seem nonsensical to you.

Yet, for product manufacturers, having quality wires with clear printed coding is necessary to support their wider manufacturing efforts. Even more importantly, these cables designate important codes that ensure a safe product for us consumers to use. In this post, we’ll be exploring what consumers should know about the print work on their cables and why it’s needed.

Why Cables are Printed

First and foremost, let’s explore why cables and other wire products often contain codes or numberings on them.

One of the most important and obvious reasons to have codes on cables or wires is to help identify their purpose. This is especially important for cables used in certain situations, like fitting electrical units or when replacing parts in a piece of equipment.

Another important reason to make sure cables are properly marked is for product safety. Warnings might be marked on certain cable products that are highly sensitive or are at risk of overheating, surges and so on. These markings are really a benefit for all consumers, including the user of the final product, the manufacturer including a cable in their product, as well as service providers like electricians or engineers.

Cables can be also distinguished not just by the coding on them, but also the color, size, length and thickness.

What Cable Markings Means

The content of the wire cable depends on its use. For consumers at home, wires feature a range of markings which explain a cable’s characteristics, most commonly:

  • T = Thermoplastic (to protect against fire damage)
  • H or HH = Heat or high-heat resistance
  • W = ‘Wet’, safe for use in moist, damp environments
  • X = Synthetic polymer, a durable material
  • N = Nylon-coating

For most of your household products, you will typically see a combination of these codes on your product’s cables. These include combinations such as THHN or THW.

Wire markings can also give other useful information to help the consumer use the cable correctly, like the manufacturer’s name, maximum voltage and more.

Other types of wires, like underground cables will have a different range of letters or codings. They will have a dull, greyish coloring, unlike household or consumer-grade wires.

Discover more about each wire marking means and its classification here.

How Cables are Printed 

Now we understand why cables need to be printed, let’s explore how cables get their markings. There are a variety of techniques to ensuring a cable or wire gets its markings, these include:

Hot Foil Marking: Ideal for use on hard-to-print surfaces, hot foil marking is where a metallic strip is heated and marked with pressure.

Hot Stamp Marking: Similar to hot foil, hot stamp marking works in the same way by using heat to directly print onto wires.

Emboss Marking: This printing technique leaves slightly raised print work on cable jackets.

Indent Cable Marking: Like emboss marking, indent marking directly prints on the cable jacket. The differences are that it can be applied to cold cable jackets and leaves an indent rather than raised print work.

Sinter Cable Marking: Sinter printing takes a unique approach by printing powder to cables. It leaves a permanent mark and helps protect the print work against corrosion or acids that could compromise it.

Cable and marking machines, like this emboss wire marker, are used to leave an impression on the cable product.

Getting quality print work is important for manufacturers as it not only gives consumers absolute transparency into the cable product, but also ensures the product meets regulations. So, next time you open up a new electronic or find yourself plugging a fiber optic cable into port, do take a moment to check its markings. You will be amazed at what you can learn from just a few lines of codes.


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