UL Certificate

To determine whether a product has been tested and certified by Underwriters Laboratories (UL), it is recommended that you first check for the UL mark on the product. This provides an initial indication of whether UL certification has been granted and for which target market—the U.S., Canada, or both countries—the mark applies.

Further information regarding the scope of certification, as well as any manufacturer-specific operating conditions and restrictions, can be verified by referring to the relevant certification documents and the entry in the official UL certification database.

What is a UL certificate?

A UL certificate is proof that a product or electrical component has been tested and certified in accordance with the applicable safety standards of Underwriters Laboratories (UL). UL certification plays a particularly important role in the U.S. and Canadian markets.

It confirms that the product in question meets the requirements of the applicable standard. A corresponding UL mark identifies the certification on the product and can facilitate regulatory approval. This is contingent upon the certification being valid for the respective target market and all specified operating conditions being met.

Roles and Importance of Underwriters Laboratories (UL)

Underwriters Laboratories (UL) was founded in Chicago in 1894 by William Henry Merrill. Today, the organization is one of the world’s leading institutions for the development of safety standards and the testing and certification of products. UL Solutions is headquartered in Northbrook, Illinois. The company also has a presence in Germany, including a location in Neu-Isenburg near Frankfurt am Main.

UL’s primary goal is to improve the safety of products, technical systems, and work environments. To this end, more than 1,300 safety standards have been developed throughout the company’s history. In addition, UL Solutions tests and certifies electrical components, materials, machinery, systems, and industrial equipment, among other things.

If a tested product meets the requirements of the applicable standard, it may receive the corresponding UL certification. This is indicated by a recognized UL mark. Maintaining certification requires continued compliance with the applicable requirements. This is verified, among other things, through regular monitoring measures.

UL Solutions is also one of the Nationally Recognized Testing Laboratories (NRTLs) recognized by the U.S. Occupational Safety and Health Administration (OSHA).

OSHA is a federal agency of the United States responsible for promoting and enforcing workplace safety and health. As part of the NRTL program, it recognizes independent testing laboratories that are authorized to test and certify certain products for compliance with relevant safety standards.

How are products tested and UL-certified?

For UL certification, not every single product is typically tested. Instead, UL Solutions examines representative samples of a specific product type to verify compliance with applicable safety standards and certification requirements.

The tests focus in particular on potential risks from fire, electric shock, and mechanical hazards. If the tested samples meet all relevant requirements, the certification may be extended to other products of the same design from the same production series.

These products may then be marked with the corresponding UL mark, provided that the specified manufacturing conditions are met. Regular monitoring and production controls ensure that the certified products continue to comply with applicable safety standards.

Every year, billions of products worldwide bear the UL mark.

Which products require UL certification?

UL certification is particularly relevant for products and components intended for use in the North American market. These include, among others:

• Information Technology and Communications Technology
• Household Appliances
• Cables and electrical wires
• Alarm and Security Systems
• Electronic Devices
• Electrical Parts and Components
• Electrical Equipment for Potentially Explosive Atmospheres
• Fire Extinguishers and Fire Safety Equipment

Whether UL certification is required depends on the specific type of product, its intended use, and the applicable legal or regulatory requirements.

An Overview of the Most Important UL Marks

A UL mark certifies that a manufacturer’s product has been tested and certified in accordance with the relevant safety standards. Regular inspections also ensure that applicable requirements are met throughout the production process.

However, there is not just a single UL certification. For the North American market, there are various UL marks and types of certification that differ in terms of their scope, the underlying test procedures, and the respective product requirements.

The following overview lists the most common UL markings and explains their meanings.

The Most Important CCN Codes for Control Panel Construction According to UL 508A

What does NITW stand for?

NITW refers to the Category Control Number (CCN) for industrial control cabinets certified in accordance with the UL 508A standard. This standard defines the safety requirements for industrial control cabinets and mounting panels intended for use in the United States.

The NITW product category includes control panels for ordinary operating environments, known as Ordinary Locations (OrdLoc). This includes areas that are not classified as potentially explosive. The corresponding electrical installations must comply with the applicable requirements of the National Electrical Code (NEC, NFPA 70).

The scope of application of the CCN NITW extends to various industrial sectors. These include, among others, control systems for production machinery, air conditioning and refrigeration systems, cranes, and elevators, as well as flame monitoring systems. Certain applications in the maritime sector and in the field of electrical power supply systems may also fall under this scope.

For the Canadian market, this product category is listed under the designation NITW7. It refers to industrial control cabinets that are certified in accordance with the applicable Canadian safety requirements.

What is NRBX?
The designation NRBX stands for the Category Control Number (CCN) in the UL 698A standard. This product category includes industrial control cabinets that are installed outside potentially explosive atmospheres but are connected to equipment within such areas via intrinsically safe circuits.

The control cabinets are located in a non-hazardous environment, while the connected equipment can be used in so-called hazardous locations (HazLoc). To ensure a safe connection, the corresponding circuits must be designed according to the principle of intrinsic safety (Ex i). For this purpose, suitable UL-listed safety barriers are used, for example, which limit the electrical energy in the intrinsically safe circuit in such a way as to prevent ignition of the explosive atmosphere.

For the Canadian market, there is a corresponding product category designated NRBX7. It includes control cabinets with intrinsically safe circuits that are certified in accordance with the relevant Canadian safety requirements.

What does NNNY mean?
NNNY is the CCN for the UL 1203 standard. This standard specifies the safety requirements for control panels intended for use in hazardous locations (HazLoc) in accordance with Articles 500–505 of the NEC, NFPA 70, which are to be installed in Classes I, II, and III, Divisions 1 and 2; Class 1, Zones 0, 1, and 2, and Groups 1A, 1B, and 1C.

There are particularly strict technical requirements for these potentially explosive areas that must be met in order for electrical equipment to be labeled as “explosion-protected” and “dust explosion-protected.”

For example, when designing control cabinets, care must be taken to ensure that no arc-prone components are present and that the control cabinets can withstand elevated temperatures, as under no circumstances should a source of ignition be created or enter the hazardous area.

The CCN for UL standards in Canada is NNNY 7.