The UL 508A certification: Why it is important

Sept. 25, 2023
The certification exists for a reason — to ensure that the control panels being built meet the very highest safety standards available.
Courtesy of Valin Corporation
A Valin UL 508A control panel.
A Valin UL 508A control panel.

The world of control panels and enclosures is not only a bit more complex than most realize but it is also very tightly regulated. As automation and industrial automation continues to grow, so does the need for high quality control panels and enclosures.

But how do we know the panels being built for a particular application make the grade? There is a significant amount of nuance involved in building a control panel, so how can the end user be confident that what they are ultimately receiving is correctly built and most important, safe.

There are elements in a control panel that must meet a certain standard for the process to be successful once implemented. There are environmental factors, safety concerns, wiring protection and proper component usage standards that all need to be met by the builder. Fortunately, the buyer does not have to simply trust that the builder knows what they are doing. Instead, there is a certification program that ensures the builder follows the proper process and approach that will meet all these requirements, the UL (Underwriters Laboratories) 508A Industrial Control Panel Shop Program.

Why is this certification important?

First and foremost, the UL 508A program is a safety standard. It was designed to improve the safety of the control panels being built along with their proper installation. The standard also applies to operator stations and motor controllers. In an industry where fires and electrical hazards are real risks, by following a global standard for safety, the UL 508A certification ensures that the panels that earn such a distinction are the safest available. 

UL is regarded by many as the standard for safety and the UL sticker placed on panels and various items provide operators with confidence that the product was built to those standards.

It is also important to understand the differences between UL 508A and UL 508. Although both are safety standards, the latter is a standard for industrial control equipment as opposed to the control panels themselves.

According to UL, its Industrial Control Panel Program covers multiple requirements such as:

  • Proper component usage
  • Enclosure environmental ratings
  • Wiring and motor protection
  • Safety markings
  • Conformance to the National Electric Code and Canadian Electrical Code

For example, the UL 508A Standard lists components and how they should be used, however there are exceptions that accompany the use of some components. For example, exception one states that equipment intended to be connected to a source of supply greater than 1,000 volts shall not be used.  The second exception has to do with the location of the component.

According to standard, “the following hazardous locations equipment and associated apparatus shall not be used as part of an ordinary locations industrial control panel:

A) An explosion-proof enclosure marked for Class I hazardous locations.

B) A dust-ignition-proof enclosure marked for Class II hazardous locations.

C) A barrier or other equipment that provides intrinsically safe input/output connections for use in Class I, II and III hazardous locations.”

The third exception is for “equipment intended for a non-industrial use such as consumer appliances and equipment for residential use shall not be used.”

This is just a minor part of the standard regarding proper component usage. What its inclusion in this discussion is intended to illustrate is the comprehensive nature of this standard and how rigorous the certification truly is.

The UL Listing Mark on an industrial control panel signifies above all else that a third party has certified the control panel to an accepted safety standard. They are the municipal inspection authority as it applies to control plans and is recognized globally as a trusted source for product compliance. The mark also has some versatility. It can be found on a wide range of designs. Whether a control panel has been completely custom built or only has minor variations, the UL508A certification can be applied to the product.

The certification has gained enough traction and universal acceptance and adherence over the years that many organizations flat out require the vendors that build their control panels to have earned such a certification.  

If there are compliance regulations associated with a facility, they cannot merely be sidestepped. There are inspectors that do regular checks on control panels in the field. If, during one of these inspections, it is determined the facility is not using a certified control panel, it can be decommissioned on the spot.

Other than a catastrophic accident, this could be considered a worst-case scenario. It causes the facility to have that panel rebuilt by a shop that is certified. As one would imagine, this is an incredibly costly exercise. Not only does the expedited build have a hefty price tag attached, but any process that needs to be shut down while the replacement is being made suffers. This cost can become very high, very quickly.

The program is very thorough, with representatives visiting the shops that build the control panels bi-monthly in order to verify that the proper methodology is being followed. This ensures the sticker attached to any control panel built by a UL 508A certified panel shop has real meaning.

This element of control engineering is not only important to be aware of, but also to have a better understanding of its ramifications. The certification exists for a reason — to ensure that the control panels being built meet the very highest safety standards available. Failure to do so not only puts the safety of personnel at risk, but can also lead to the unnecessary costs associated with reaching compliance if it is not built properly in the beginning. The first step in your research should be to find a UL 508A certified control panel shop to assist you with your build. They can custom build panels from the ground up, or bring existing control panels up to UL safety standards.

Jason Gaines is an engineering manager at Valin Corporation, a leading technical solutions provider for the technology, energy, life sciences, natural resources and transportation industries. Valin offers personalized order management, on-site field support, comprehensive training and applied expert engineering services utilizing automation, fluid management, precision measurement, process heating, and filtration products. For more information, please visit

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