Which is Better – UL Listing, ETL Listing, MET Listing or CSA Listing?

Many areas require an independent laboratory listing be visible on electronic signs of any kind in order to provide a permit for installation. So, logically, it is often sought after. However, it can be extremely difficult to make sense of how an independent testing facility like UL, ETL, MET, or CSA, or others affect the way you should view the quality of any given product. The sign and display industry has made this particularly difficult since each company tries to make the case for their listing, or lack thereof, leaving you at a loss as to the truth of the matter. In this post, we’ll break down each of the top 3 listings to help separate the sales and marketing talk from the real truth of each. We’ll also include a few nuggets of info to help you decipher these options and verify them for yourself.

But first, it is important to understand just how these listings are given. Whether it is a single component, or a whole solution, like an LED church sign, for example, each manufacturer must pay the laboratory to submit their products to testing. The manufacturer works together with the laboratory to fix any issues causing the component or solution to fail any given test. Some laboratories also require regular visits to the manufacturer’s factory (usually 2-4 times per year) in order to verify that standards are being kept. These processes can be extremely costly, resulting in a higher-priced product in most cases.

#1 UL Listing (Underwriter Laboratories)

UL has been around the longest of the independent testing facilities and is widely recognized as a measure of quality and safety. For this reason, many sales companies and manufacturers alike tout UL as their quality standard.
However, claims do not always match up with the truth in these circumstances. The reason for this is that there are different types of UL Listings. You will often hear claims like UL Compliant, fulfills UL standards, or made with UL Listed components. These are red flags. Many factories use one or more components that are UL Listed, but leave the rest without any testing to cut costs while providing a quality statement.
The correct full listing of any given sign solution should read “UL Listed” with the trademarked UL Listed logo (see below).
UL Listed LED Signs Guthman Signs x

Also, UL knows this is going on in many markets so they provide a free search tool where you can verify any company’s claims of being UL Listed. You can access that tool here:


#2 ETL Listing (Edison Testing Laboratories)

The benefit of using ETL as the lab of choice for manufacturers is that they have a lower cost, and testing is generally a quicker process from start to finish, making it easier to innovate and change products while maintaining a quality listing. ETL is recognized by most of the same entities that accept UL Listing standards. The general rule is that ETL recognizes UL standards, but UL does not recognize ETL standards. Most experts in the signage industry, including outdoor LED signs, recognize both listings as acceptable. However, since ETL is lesser-known, many buyers feel it is substandard simply for the difference in brand recognition.

The ETL mark should be verified equivalent to the logo seen below.

ETL Listed LED Sign Ratings Guthman Signs x

Many claims are made for ETL compliant products etc , much like the UL claims outlined above. Thus, ETL has also provided a search tool to allow buyers the power of verification. You can access their database search tool, here:$$Search?OpenForm


#3 MET Listing (Eurofins)

In the past, MET laboratories were a competitive alternative to UL and ETL due to lower cost and a focus on OSHA standards rather than varying from those standards to create new required verifications that are billed to the manufacturers using their mark. In recent years, MET has grown enough that they decided to adopt the same tactics as ETL and UL in this sense, now requiring manufacturers to verify, and re-verify components and solutions previously confirmed as a way to make more money. However, MET laboratories do still focus on the OSHA requirements as a tactic to further verify their standing as a solid testing choice. Today, MET is an alternative that is still somewhat less expensive than ETL and UL, so many manufacturers are adopting the MET mark as their preferred show of compliance with quality and safety standards. MET visits factories 2 times per year for verification compared to up to 4 times a year required for many UL listed factories, depending on their size.

Most permitting offices accept MET marks for permitting in signage, but it is always a good idea to verify first before purchasing a MET labeled product for your outdoor electronic sign project, just to be sure.

It is always a good idea to verify the MET listing logo seen below as well.

MET Listed LED Signs Rating Guthman Signs x

MET Laboratories certification directory can be searched for verification purposes here:


#4 CSA (Canadian Standards Association) Group

Some people may not recognize the CSA mark, but it has indeed been a very reliable International Standards Development, Testing, Inspection, & Certification company based in Canada for over one hundred (100) years. Initially focused on building energy standards, they have branched into all fields including mental health and safety, and electronics including electronic signage such as LED signs and marquee displays as well.

In 1992 The United States Occupational Safety and Health Administration accredited CSA as a Nationally Recognized Testing Laboratory (NRTL). See notes below concerning the NRTL Listing process and background.

Manufacturers have claimed that CSA is much easier and more logical to work with because they have fewer fees and penalties. Reports are clear that CSA is more willing to allow for corrections to an issue prior to charging fees or penalties. This is at times seen as a weakness to the validity of the CSA mark. This is incorrect however, as such a perspective neglects to take into account that improvements still result from regular factory inspections. CSA proponents argue that this process is much better than draconian fees making, because it allows manufacturers to more freely expose issues and subsequently learn from them in much more effective fashion than perhaps they would have if they feared fees or other repercussions. 

The CSA mark should be verified equivalent to the logo seen below.

CSA Logo

CSA Group’s Product Listing directory can be searched for verification purposes here:

For more information on CSA Electrical Product Standards see here:

A note on NRTL Listing (Nationally Recognized Testing Laboratory)

You might notice claims concerning NRTL Listings for quality and safety standards while doing product research. NRTL is a program started by OSHA, and MET was the first to adopt this mark. The goal was to standardize the testing standards provided by the US government. However, this left UL, ETL, MET and others to simply add on to the OSHA standards as a way to set themselves apart as going above and beyond national standards, primarily as a marketing tactic.

If you have any more questions, please don’t hesitate to contact our team of sign experts!


Let us help you make a well-informed purchase. Contact Guthman, your digital experts, for the best LED signboards in the industry.