Panel builders can prevent costly safety and compliance problems by knowing the latest changes to key standards and regulations.
When control panels are being conceived and created, developers often say they’re focused on the needs of the customer. Savvy designers often add another focal point: the regulators and industry groups that set standards that must be included from the outset of the design cycle.
Standards that come from a number of regulatory bodies must often be considered in the critical field of control panels. Though standards organizations are often slow moving, it’s always wise to keep an eye on these regulations to make sure that developers don’t get tripped up by designing to an outdated document.
An aptly-named webinar, Codes and Regulations for Panel Builders, provides a broad view of the standards environment as it concerns control panels. It addresses some of the recent changes while also serving as a refresher for experienced staffers and a tutorial for design team members who haven’t yet learned the nuances of understanding standards and making them an integral part of the end product. One of the most important is from Underwriters Laboratory.
“UL 508A is the real governing document for designing industrial panels,” said Jeff Woolfolk, one of two Siemens experts.
Jim Sirois listed other standards that often play a role in products designed for domestic and global markets. The Occupational Safety and Health Administration, the National Fire Protection Association, the American National Standards Institute and the Canadian Standards Association are the dominant players in North America. Though the two focus primarily on North America, they also noted that IEC requirements will play a role for companies that sell into Europe.
In North America, the venerable UL 508 is gradually being displaced by an enhanced mark. The newer version provides more information, primarily the country of origin and a file number. The latter makes it easier to find information about the product.
The enhanced edition, now in the later stages of a 10-year phase-in period, won’t impact existing products that don’t have the new mark. It doesn’t come with additional requirements, so its impact is relatively small. One of the biggest challenges is that providing more information means taking more space. That’s an issue for push buttons, contactors and other small components that don’t have room for a larger label.
At the same time, UL 508 is migrating to UL 60947. This change is being made to harmonize UL 508 with IEC 60947, the international standard for Low-Voltage Switchgear and Controlgear. While the nomenclature will be different, compliance won’t change.
The UL website tells you that technically, UL 508 and UL 60947 are exactly the same,” Woolfolk said. “What happens in a few years is hard to say, but that’s the way it is now. The actual impact is zero at this time.”
While UL has moved to harmonize with the IEC, it’s currently not in harmony with the National Electrical Code. In 2014, the NEC changed the definition of low voltage to 1 kV or less. That’s up from the previous U.S. definition of 600 V. It’s likely that UL will change its requirements, though nothing has yet been formalized.
Another change came in 2014, when UL altered the protection requirements for circuits above 32V. If a control panel has circuitry above 32V, it must have a dc protective device. Below 32V, a dc-rated protective device is not necessary.
Sirois noted that air conditioning is no longer part of the short circuit current calculations for products that are cord connected or are supplied by branch circuits that are protected to 60 amps.
“A lot of air conditioners have just one or two amps, which is hard to work with. Some parts don’t go that small,” Sirois said. “That’s very helpful if you’re doing any type of cooling on a panel. Eliminating this requirement helps to maintain a higher panel SCCR rating.”
The reach of the UL standard is also expanding. In recent years, control panels for fountains and irrigation systems must now comply with the document.
Both Sirois and Woolfolk touched on the compliance differences between IEC and UL. Design teams working towards IEC compliance must select the relevant standards for their project and meet them, then create a declaration of conformity saying that they’ve met the standards. They can then put a certificate on the product. IEC puts the responsibility for safety on the owner, operator and manufacturer of the equipment.
In the U.S., companies must go to a third party company that will ensure that the product meets the relevant safety requirements. These companies, called authorities having jurisdiction, certify compliance. That’s often easier than self-qualifying, the two speakers agreed.Have an Inquiry for Siemens about this article? Click Here >>