Dear Leonard,

Great question! UL is the American safety consultancy company previously known as Underwriters Laboratories. They set and administer a wide range of standards, including those for electrical and electronic products.

UL standards scrutinise the entire manufacturing process, from source materials to manufacturing and packaging. While UL approval is particularly important to American markets, their 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 (harmonized with the IEC 60947 series)

It’s worth knowing that the UL508 standard is no longer tested for new products, but existing products (like many Spelsberg 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.

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

It is fair to assume that products with UL markings bought from reputable manufacturers or distributors are legitimate. If you have concerns about the product, you would be within your rights to contact your supplier and request details of 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. Find out more about our [UL tests] and testing methods as well as [IEC-/EN testing] on the Spelsberg website or drop me a message if you’d like more specific information about the Spelsberg range of UL-approved enclosures.

Kind regards,

Chris