How do you know if an enclosure is UL approved?

UL-approved enclosures display a UL mark on their casing. Sometimes this is a standard UL mark, but you might also see variants such as C-UL US in Canada or UL-EU in the European Union. You may also find an RU mark: these are used on components of UL listed products that cannot carry the full logo themselves.

UL is the American safety consultancy company previously known as Underwriters Laboratories. It sets and administers a wide range of standards, including those for electrical and electronic products. UL standards scrutinise the entire manufacturing process, from source materials through to manufacturing and packaging, and while UL approval is particularly important to American markets, the markings are recognised internationally.

The relevant standards for enclosures are:

• UL94 – Tests for Flammability of Plastic Materials for Parts in Devices and Appliances

• UL746C – Polymeric Materials: Use in Electrical Equipment Evaluations

• UL50 – Enclosures for Electrical Equipment, Non-Environmental Considerations

• UL50E – Enclosures for Electrical Equipment, Environmental Considerations

• UL508 – Industrial Control Equipment (harmonised with the IEC 60947 series)

It is worth knowing that the UL508 standard is no longer tested for new products, although existing products, including many of our enclosures, can stay accredited as long as they continue to undergo testing. IEC 60947 is the internationally recognised standard to look for in new products.

It is fair to assume that products with UL markings bought from reputable manufacturers or distributors are legitimate. If you have concerns about a product, you would be within your rights to contact your supplier and request details of the testing procedures.

All Spelsberg enclosures undergo rigorous in-house testing in our UL-audited test facility. This means you can rely on high manufacturing standards for your enclosures.