UL or Underwriters Laboratories, is an independent, non-profit global safety certification company and testing laboratory headquartered in Northbrook, IL. UL conducts safety and quality tests on a broad range of products including more than 70 different wire and cable product categories to national and international standards for safety, performance, quality, environmental impact and regulatory compliance.

In other words, they test products for the above-mentioned safety standards, but they do not “approve” products, a misconception. Manufacturers submit products to UL for testing and safety certification on a voluntary basis. There are no laws specifying that a UL mark must be used, however, in the United States many municipalities have laws, codes and regulations which require a product be certified by a nationally recognized testing laboratory before it can be used. With over 125 years of testing and certifying, UL is the largest, oldest and most recognized laboratory listed and a mark that you find on almost all electronic products in your home or office.

There are (2) main designations of UL and they are very different.

UL Recognized is granted to components that are used in combination with other components to create a finished product. These components have been tested for specific applications in end products.

UL Listed means the product has been tested and meets the laboratory’s standard to be used by itself for a specific purpose.

UL Classified products have been evaluated only for specific properties, a limited range of hazards, or suitability for use under limited conditions. These products have more specific, limited purposes.

What does this mean for wire and cable?

Let’s put it in terms of an industrial machine system where you have a machine, the control cabinet and the wiring in between the machine and the control cabinet using a cable tray system.

A common use of UL Recognized wiring is on the machine and within the control panel or cabinet. The largest UL category for wire and cable – Appliance Wiring Material (AWM) is commonly used in a variety of applications such as general-purpose wiring circuits and internal wiring of appliances. AWM is always considered a “Recognized” component evaluated for specific uses, outlined by the style number printed on the jacket. These wires are not intended for field installation but rather for factory installation in an overall Listed or Classified product. In our example, the entire machine and control cabinet will be listed and would ship with this type of wire already installed.

UL Listed wire and cable describes field level wiring going to and from the machine, making connections to other machines, control cabinets, power source or equipment via an open or closed cable tray system. These cables are UL Listed for their specific use in the field, governed by the National Electric Code (NEC) and require more stringent tests and higher flame-retardant properties. TC or “tray cable” is a UL Listing and common in field wiring of industrial machine systems due to it’s acceptance per the NEC for installation in cable tray. We discuss this listing and others in the article “UL Listings for wire and cable”.

Right Hand Industrial can supply a wide range of UL Listed and Recognized wire and cable, including cables with multiple listings for broader installation options. Let’s discuss your application today.