Don’t Get Left Behind Understanding the New VFD Cable Design Requirements

Belden Cable

With the hustle and bustle of everyday life, it is sometimes hard to keep up with all requirements and changes in our industry. One of the new updates this year is the VFD cable design requirement released by National Fire Protection Agency (NFPA) 79. In response to this announcement, we want to help you understand what it means and why it is important to you and your business.

First, what is a Variable Frequency Drive (VFD) Cable?
VFD controls the frequency and voltage supplied to your electric motor and controls the motor speed and torque. The VFD cable connects the VFD and electric motor to help build a reliable system that reduces downtime. VFD cables can be used in applications ranging from small appliances to large mine mill drives or compressors.

Second, what does the new VFD cable requirement say?
You can find the new VFD cable requirement in paragraph 4.4.2.8 of NFPA 79 / 2018 Edition. The requirement states that “Electrical conductors and equipment supplied by power conversion equipment as part of adjustable speed drive systems and servo drive systems shall be listed flexible motor supply cable marked RHH, RHW, RHW-2, XHH, XHHW or XHHW-2.”

Use of the approved materials for VFD cables discussed in the new requirement will help to provide long-term cable performance and help eliminate the risk of downtime due to cable failure. According to Lutze’s whitepaper, How NFPA 79 2018 Edition affects VFD cable, they discuss how the new requirement is aimed to “reduce the use of thermoplastic wiring material that is not capable to withstand the output and currents from VFD utilizing pulse width modulation.”

Third, why is the new VFD Cable requirement important?
You need to be aware that not just any VFD cable will work for your applications. According to Belden’s whitepaper, Selecting Compliant VFD Cable Under NFPA 79, “The VFD cable market has been marred by an assortment of products described by the manufacturers as VFD cables, but lacking the essential properties required to perform effectively and reliably in many applications."

Finally, what to look for in a VFD Cable?
When purchasing VFD cables, make sure they are marked with one of the following - RHH, RHW, RHW-2, XHH, XHHW or XHHW for your VFD applications to help ensure that it runs smoothly – both Belden and Lutze are manufacturers of the material and are in compliance with the new VFD cable requirement. McNaughton-McKay and its supplier partner, Omni Cable, can work with you to make sure you are buying the correct VFD cable that meets the new NFPA 79 requirements. If your VFD cable fails, it can become a safety issue and be costly for your customers in the end; this in turn can hurt your business and reputation.

 

Posted on Monday May 14, 2018 | 79, cable, drive, nfpa, vfd, wire,

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