Getting to know NFPA-79

NFPA-79 is the section of the National Electric Code (NEC) that focuses on electrical wiringstandards used with industrial machinery. It applies to the electrical components installed in avariety of machines, as well as groups of machines working together, such as machine tools,injection molding machines, assembling machinery, and material handling equipment. The scope ofNFPA-79 includes all electrical and electronic elements operating at 600 V or less.

In 2007, the NFPA-79 code underwent significant revisions in order to harmonize with its European counterpart, IEC-60204. One of the major changes involved cable selections required under Section12.2.7.3. This section states that single conductor or multi-conductor AWM (Appliance WiringMaterial) is not permitted, unless the completed assembly has been listed prior for such use.

The change was added because, in many cases, AWM was being used incorrectly during machinery installation. Some installers were running AWM from the main source of power (circuit breaker orfuse box) to the machine's control panel. That's a problem. In other cases, improper use of AWMwas creating fire hazards. Machine Tool Wire (MTW), on the other hand, is one of the permissible options for wire and cable under the revised code.

Another requirement for machine cable is that it must be clearly labeled (on its jacket surface) with a UL symbol instead of the Recognized Cable Component (RU) logo, more commonly known as AWM. In cases where questions arise, the local inspector is the authority having jurisdiction in thearea, and their interpretation of NEC code regulations is the final decision. It's their job to keep non-listed products out of industrial installations. And when an inspector shuts down a facility, no further installation work is permitted anywhere on site.

It's important to note that NEC code interpretations can vary greatly among inspectors; for example,

what's considered acceptable in New York State may not be acceptable in New York City. To ignore cable-specific requirements or consider them as secondary can be a costly mistake, or in worst-case scenarios, a hazardous and life-threatening decision.

Key definitions: Regulatory agencies, functions

NFPA - The National Fire Protection Association (NFPA) acts as the sponsor of the NationalElectrical Code (NEC). The NFPA has no power to enforce compliance with the NEC's contents. TheNFPA does not list, certify, test, or inspect products, designs, or installations for compliance with theNEC, nor does it guarantee the accuracy of information published in the NEC.

NEC - The National Electrical Code (NEC) is considered purely advisory as far as the NFPA isconcerned. It is made available for a variety of public and private uses in the interest of life andproperty protection. These include use in law and for regulatory purposes, as well as use in self-regulation and standardization activities such as insurance underwriting, building construction andmanagement, and product testing and certification.

UL - Underwriters Laboratories Inc. (UL) is an independent, not-for-profit, product-safety testing andcertification organization. No laws specify that a UL mark must be used. However, in the U.S., manymunicipalities have laws, codes, or regulations that require a product to be tested by a nationallyrecognized testing laboratory. UL does not, however, maintain a list of the jurisdictions having suchregulations.

Authority having jurisdiction - The organization, office, or individual responsible for approvingequipment, materials, installation, or a procedure.