What Is cULus?

cULus is a UL safety mark showing that a product has been tested and certified by UL Solutions to both Canadian and US safety standards. The small “c” to the left of the UL logo stands for Canada and the “us” to the right stands for the United States, so one certification covers both markets.

The mark matters because electrical equipment installed in North American workplaces is expected to carry a recognised safety certification. In the US, OSHA rules call for equipment to be listed by a Nationally Recognized Testing Laboratory (NRTL), and UL Solutions is one. In Canada, provincial electrical codes require approval by a certification body accredited by the Standards Council of Canada (SCC), and UL Solutions is accredited for that too. Inspectors, insurers and end customers look for the mark on the nameplate.

A cULus mark is not a one-off test. The manufacturer’s factory is visited by UL inspectors on an ongoing basis to check that production still matches the product that was certified. The mark normally sits on the rating label next to the word Listed or Recognized and a UL file number, which is the reference you use to check the certificate.

The letters around the logo tell you which country’s standards the product was assessed against, and the type of mark tells you how it may be used.

For a buyer in North America, cULus, cCSAus and cETLus are accepted the same way: each shows certification to the same published standards by an accredited laboratory. UL Solutions has also been introducing a newer UL Certified mark that names the countries covered, so both styles appear on products in service.

Listed applies to a complete, stand-alone product, such as a computer, a power supply or a switch, that has been assessed for its intended use. Recognized applies to a component, such as a power supply module, relay or fan, assessed for use inside a larger product. A Recognized component carries conditions of use, and the end product still needs its own certification.

The difference matters most to control panel builders. A panel built to UL 508A is easiest to certify when the parts inside are Listed or Recognized for that use. Our white paper on how UL-certified computers help control panel builders covers this in more detail.

cULus is a mark, not a standard. The certificate names the standard the product was tested against, and that depends on what the product is.

The two marks answer different questions. CE shows that the manufacturer declares the product meets EU directives, such as the Low Voltage, EMC and RoHS Directives, and in most cases no independent laboratory is involved. cULus shows that a third party has tested the product to North American standards and keeps inspecting the factory. A product sold on both sides of the Atlantic usually carries both, and in Great Britain the UKCA mark is accepted alongside CE.

In our range, many industrial Ethernet switches list UL 61010-1 certification, some with Class I, Division 2 as well, and several industrial panel PCs list cULus certification to UL 62368-1. Always check the product’s own datasheet and certificate, because approvals differ between models in the same series.

We supply the compliance documents that come with each system, and we can shortlist computers, panel PCs and switches whose datasheets list the North American approvals your installation needs.