Control Panel Markings – Labeling of Industrial Control Cabinets

A UL mark on a control cabinet confirms that it has been tested and certified in accordance with the relevant UL safety standards, such as UL 508A. It indicates that the control cabinet meets the specified requirements for electrical safety and compliance with standards.

The UL mark thus provides manufacturers, facility operators, and regulatory agencies with important evidence of compliance with applicable certification requirements.

Control Panel Markings and UL Markings—What Do They Mean?

Control panel markings are markings on industrial control cabinets that contain important technical specifications and information regarding compliance with relevant safety standards. They are usually affixed as nameplates or labels.

If it is an official UL certification mark, it is referred to as a UL marking or UL label. These confirm that the control cabinet has been tested and certified in accordance with the applicable UL certification requirements, such as UL 508A.

Are control panel markings required for control cabinets?

A UL mark is not generally required by law for industrial control panels in North America. However, certain technical markings (control panel markings) are required under applicable safety regulations.

When exporting control cabinets to the U.S. and Canada, UL certification can offer significant advantages. UL Solutions is one of the best-known and longest-established testing and certification organizations in North America.

A corresponding UL label often facilitates approval by the relevant regulatory authorities (AHJs) and serves as recognized proof of compliance with relevant safety standards.

Why UL Marking Is Often Essential

Many wholesalers, facility operators, and insurance companies require that electrical products have recognized UL certification. As a result, the UL mark plays an important role in gaining market access in North America.

This certification mark is particularly important for the acceptance testing of industrial machinery and equipment in the United States. The competent authority, known as the Authority Having Jurisdiction (AHJ), verifies compliance with applicable safety regulations.

A UL mark serves as recognized proof of certification and can significantly simplify the testing, acceptance, and commissioning processes.

Control Panel Markings from Other Testing Laboratories

In addition to UL, other recognized testing organizations may also issue control panel markings for industrial control cabinets. These include, for example, Intertek, FM Approvals, and TÜV SÜD, which are also recognized by the U.S. Occupational Safety and Health Administration (OSHA) as Nationally Recognized Testing Laboratories (NRTLs).

In principle, their certification marks can serve as equivalent proof of safety within the respective scope of recognition. In practice, however, some plant operators, customers, or insurance companies expressly require a UL certification mark.

It is therefore important for manufacturers to determine, before exporting control cabinets to North America, which certifications are accepted by the client and the relevant regulatory authority (AHJ).

Which UL markings are relevant for control cabinet construction?

There are numerous UL marks that differ in terms of their certification type and scope of application. While some marks are intended exclusively for specific products, others have no direct relevance to industrial control panel construction.

Below, we present the most important UL markings for control cabinets and explain which certification marks are particularly relevant for manufacturers, plant operators, and buyers of control cabinets.

UL Listing Mark – Certification of Finished Products
The UL Listing Mark is one of the best-known UL certification marks and is also used on our UL-certified control cabinets. It confirms that representative product samples have been tested and meet the relevant safety requirements.
Regular inspections of production facilities ensure that the manufacturer consistently complies with the applicable certification requirements. The UL Listing Mark thus provides important proof of safety for manufacturers, plant operators, and regulatory authorities.

Recognized Component Mark – Marking of Tested Components
The UL Recognized Component Mark identifies components intended for installation in larger devices or systems. For purchasers of ready-made control cabinets, this mark is generally less relevant.
However, UL Recognized Components play an important role in control cabinet construction. Since these components have already been evaluated by UL with regard to specific safety requirements, their use can simplify the certification process for the entire control cabinet.
This is contingent upon compliance with the specified installation conditions and usage restrictions. As a result, testing efforts and certification costs may be reduced under certain circumstances.

UL Classification Mark – Testing of Specific Characteristics
The UL Classification Mark is awarded to products that have been tested for selected safety features, characteristics, or operating conditions.
Unlike the UL Listing Mark, this certification applies exclusively to the specified test criteria. For example, the evaluation may pertain to specific environmental conditions or individual safety risks.
The certification mark thus confirms compliance with specific UL requirements without automatically demonstrating a comprehensive safety evaluation of the entire product.

Field Evaluation Label – On-Site Testing
The Field Evaluation Label is issued as part of an individual evaluation of electrical machines, systems, or control panels at the site of use. Such a field evaluation may be required, for example, if a system lacks appropriate product certification or has been custom-built.
Upon successful testing, the evaluated equipment may receive a corresponding Field Evaluation Label. This serves as important evidence of electrical safety for the competent testing authority, known as the Authority Having Jurisdiction (AHJ).
An existing UL Listing Mark on the control panel can facilitate the field evaluation of the entire system, as the certified electrical equipment does not need to be re-evaluated in its entirety. However, the final decision regarding acceptance and commissioning rests with the competent authority.

How Different UL Markings Complement Each Other

In addition to the certification marks mentioned above, there are numerous other UL markings; however, these are less relevant to industrial control panel construction. The key point is that the various UL certifications can complement one another effectively.

Thus, the use of UL Recognized Components often simplifies the certification process for a control cabinet and, consequently, the granting of the UL Listing Mark. A control cabinet that is already UL-certified can, in turn, reduce the testing effort required during a field evaluation of the entire machine or system.

The targeted use of appropriate UL marks can therefore simplify certification processes, reduce costs, and facilitate the approval of electrical systems in the United States. This is always contingent upon compliance with the relevant safety requirements and installation conditions.

Further Development of UL Markings

With the UL Enhanced Certification Mark and the Smart UL Certification Mark, UL has introduced additional labeling options to meet the increased demands for product safety and transparency.

These are not separate types of certification, but rather extensions of existing UL marks, specifically the UL Listing Mark and the UL Classification Mark.

The new labeling formats allow for more precise identification of certification status and make it easier to access additional information about the tested products.

Enhanced UL Certification Mark – Additional Certification Information

The Enhanced UL Certification Mark supplements existing UL certification marks with additional information about the respective certification. This includes the certification category and the geographic scope.

Terms such as “SAFETY” or “ENERGY” indicate whether the certification relates to product safety or energy efficiency, for example. Country codes such as “US” or “CA” identify the respective target markets.

Using a unique UL file number—for example, E12345—you can look up additional information about the certified product and the manufacturer in the official UL certification database.

Smart UL Certification Mark – Certification Information via QR Code

The Smart UL Certification Mark contains the same information as the Enhanced UL Certification Mark, but is supplemented by a QR code. This code provides direct access to additional information about the respective certification in the UL database.

Manufacturers may use this mark on a voluntary basis to provide customers and regulatory authorities with quick and easy access to certification information. There is no general requirement to use the Smart UL Certification Mark.