Success Depends on the Crimp: Understanding the UL-486F Standard for Bare and Covered Ferrules

If you were not able to attend our Product and Technology Expo, we didn’t want you to miss out on some great information! Panduit hosted a seminar on Understand the UL-486 Standard for Bare and Covered Ferrules. Let’s dive right in!

First of all, what is a ferrule? Ferrules are terminals that only have a barrel. They effectively prevent straying of wire strands.

But what is the difference between a Pin and Ferrule? They both serve a similar purpose, but the pin terminal is larger. The final connection point with a pin terminal is not on the wire itself, but on the separate pin. The ferrule is smaller for the same wire size. With terminal blocks becoming more and more dense, the smaller footprint is an advantage. The final connection point with a ferrule is on the wire itself, and not on a separate pin.

The evolution of ferrule standards started with DIN. Ferrules have been used in applications for many years in Europe, and is required in most control panel applications. Ferrules standards started with DIN and was adopted by CAS in 2004. UL then allowed for the use of ferrules in accordance with UL-508A. Finally, UL and CSA worked with NEMA to develop the current standards that were released in 2014.

CSA listing were based on DIN. Basically, if a manufacturer had their ferrules listed as DIN, you could obtain CSA. However, as more questions arose over time regarding ferrules, CSA realized the need for a true standard which covered more than the Dimensional Requirements and/or references.

As more customers started using Flex Cable, UL saw the need to address the issue, but had not yet finalized a true listing for ferrules. In the interim, UL-508A allowed for the use of ferrules within a control panel with several restrictions. This approval did not offer customers assistance on how to test or inspect the final crimped ferrules.

Finally, in March of 2014, UL released the harmonized UL and CSA Ferrule Standard UL- 486F and CSA C22.2 No 291. This harmonized CSA Group and UL standards for bare and covered ferrules.

UL-486F and CSA C22.2 No 291

General Scope:

  • Intended for field and factory wiring
  • Facilitate connection of stranded wire to a device
  • Suitable for use with 1/0 – 20 AWG stranded wire to a device
  • Terminated in wire connection devices rated for solid conductors
  • Not intended for use in IDC
  • Does not apply to pin adapters covered by UL 486A-486B


  • Materials- copper and tin plated
  • Flammability- coverings shall have minimum classification of UL94HB
  • Thermal properties- covering shall have minimum relative thermal index of 80 degrees Celsius

Test Requirements

  • Tensile test- shall not visibly move within the ferrule or be pulled out
  • Mold stress relief- no warpage, shrinkage or other distortion
  • Dielectric voltage-withstand- plastic sleeve shall withstand the applied potential without breakdown

Sampling Requirements

  • Three samples of each assembly requirement
  • Four assembly requirements
  • Conducted for each wire class
  • Conducted for each tool being listed

Ferrule Offerings

  • Standard Ferrules
  • Expanded sleeves
  • Short circuit sleeves
  • Twin ferrules
  • Large wire ferrules up to 500 kcmil (with and without sleeves)
  • Ferrules on reel and mini-reels
  • Tools (hand tools, battery powered, automated wire stripped/crimper)

When selection ferrules and wire terminals, from ring forks, disconnect, lugs, etc., you will want to work with a company who can help ensure the product is not only UL listed, but that the product is installed correctly.

Take a look at this photo. Is there anything you can identify which may be an issue?


Did you know?
The leading reason for warranty claims on electrical assemblies is due to poor electrical connections, like the ones pictured here. To see the full presentation, check out the Product and Technology Expo page HERE.

For more information on ferrules or to get a quote on products, please contact your French Gerleman Account Manager or complete an info request form HERE.

Ferrules Panduit UL-486F