If you find electrical safety standards confusing, you’re not alone. Many machine builders have recently had to grapple with an ambiguous round of changes to NFPA–79, the portion of the National Electrical Code that governs the electrical wiring of industrial machines.
The most important change to NFPA–79 for 2012 involves the ability to use Appliance Wiring Material (AWM), which had been banned since 2007.
AWM can be a cost-effective wiring choice compared to higher-performing UL listed Machine Tool Wire (MTW). And though there had been some [sound technical reasons behind the ban](link to white paper download), high-quality AWM can be a valid wiring choice if properly specified.
One company that has successfully navigated the shoals of the changes related to AWM usage is Krones Inc., a manufacturer and integrator of packaging lines for some of the world’s best known food and beverage companies.
Krones’ engineering team recently found that compliant AWM usage does require a bit of extra effort compared to the automatic compliance found with listed UL wire. “Whenever you have to implement changes to an electrical code, there’s definitely an engineering labor factor,” says Mike Nelson, the Krones engineer charged with NFPA–79 compliance.
Some of that engineering labor has gone into researching into specific AWM products to see whether they meet the compliance restrictions. Even proper jacket labeling doesn’t answer all the compliance questions regarding AWM, “so you can’t tell whether a product complies just by looking at the cable,” says Nelson. More engineering labor has been devoted to NFPA–79’s documentation requirements.
In all, Nelson estimates that Krones has spent more than 150 engineering man hours complying with the requirements related to AWM use. And that figure represents just work done to formulate a compliance strategy. It does not include the technical documentation and drawing changes needed for each and every machine.
For more information about NFPA-79 compliance, download our latest white paper. Or contact the experts one our application engineering team for compliance help.
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