While navigating UL can be confusing, UL 698A can be even more difficult to understand. This is because this UL certification has two very different sub-designations: NRBX and NNNY . Manufacturers of industrial control panels (ICP) must diligently comply to ensure they design, manufacture, deliver, and install appropriate control panels for their applications. It is also important for purchasers of control panels to understand that the application and environment of the ICP should be known, as the safety features and UL certification vary.
Understanding 698A: What are the differences between NRBX and NNNY designations?
If you are looking for a short answer to the question, it is relatively simple: The key difference between the NRBX and the NNNY designation is the location where the control panel will operate once installed.
First, the NRBX designation for UL 698 is for industrial control panels that will feed into or control hazardous locations. This UL698A designation further states that these control panels cannot be located in hazardous locations. For example, a 698A certified industrial control panel, certified to the NRBX designation, requires “intrinsically safe” components, such as control circuits. These “intrinsically safe” components shall mitigate ignition risks as the environments will likely be near, but not in, environments where flammable gases, vapors, liquids, combustible dust, or any other particle-igniting elements may be present. In simple terms, to be “intrinsically safe” means to be usable around gases or fuels without risking static electricity or heat exchange causing ignition with the surrounding volatile particles. This designation includes industrial control panels in unclassified locations with intrinsically safe circuit extensions into the following hazardous (classified) locations in accordance with NEC NFPA 70: a) Class I, Division 1, b) Class I, Zone 0 and Zone 1 AEx, c) Class II, Division 1, d) Class III, Division 1, and e) Zone 20 and Zone 21 AEx.
While NRBX control panels are located away from the hazardous locations, UL698A category NNNY ICPs are located in an environment that has the presence of flammable gas, liquid, vapor, or dust. Due to the increased risk of peril, the NNNY designation for industrial control panels certified to UL 698A is much more stringent. These hazardous locations require special care when electricity is introduced, such as with controls and control panels. Because explosions are a risk, any industrial electric control panel certified to 698A with the NNNY category designation must be built in a panel capable of containing any possible explosions of circuitry, sparks, or arcs within the electric control panel. The industrial panels, designated as NEMA Type 7 panels, must also be non-incendive, meaning they cannot start or catch fire.
What is the Difference in UL 698A Classes, Groups, and Divisions?
If an industrial control panel will be used in an area that is designated as a hazardous location under NEC NFPA 70 Articles 500 through 503, then a UL698A certification is required. For a brief overview of the descriptions of Classes I and II Divisions 1, 2, and 3, and definitions of Groups as outlined by NEC, please refer to the infographic, Hazardous Location Designations, for additional details.
Trust the Experts at McIver for Hazardous Location Panels
Since 1978, McIver Engineering and Controls has been designing and manufacturing industrial control panels to UL certifications. With thousands of panels still in operation in applications from underground mining to dairy processing and everything in between, we have solidified ourselves as a trusted manufacturing partner for some critical applications. If you have a question on your design, or would like to discuss how we can deliver a quality, safe control panel for your application, contact our team today!