Companies that operate internationally and offer electrical equipment require international approvals. For the US and Canadian markets, the UL and cUL standards are well known. Less familiar are the IP standards, i.e. the North American protection classes for enclosures, which are summarized in the UL rating types for indoor and outdoor use.

Among other things,Lütze offers certified control cabinet accessories in accordance with UL 50E UL ratings types 2, 3R, 4, 4X, 12 and 13. The Cablefix cable entry systems X and ONE, tested according to UL ratings types 4X, 12 and 13 for prefabricated or non-prefabricated cables, offer a wide range of clamping ranges from 3.5 mm to max. 29.5 mm and are oil-resistant. The control cabinet installation boxes for front mounting are available either as an RJ45 connection with Cat.6a or alternatively with a USB 3.0 interface. In addition to a wide range of different types of protection, such as IP65, both flush-mounted boxes comply with UL Type 4X.

Enclosures must protect active parts from adverse environmental conditions, e.g. prevent the ingress of foreign bodies such as dust and water and provide shock resistance. In Europe, this enclosure protection is usually defined in the protection classes IP 00 to IP 69K. The IP protection class specifies various environmental conditions and the protection of people against potential hazards during use. Basically, the higher the IP code number, the higher the degree of protection of the enclosure.

If you look beyond the borders of Europe, a NEMA 250 or UL 50E classification is used instead of IP protection. The UL ratings are just as recognized as the IP protection types in Europe and are generally required in the USA, Canada and Mexico. NEMA stands for "National Electrical Manufacturers Association" and is an organization that sets technical standards for the US electronics industry. NEMA's performance criteria and test procedures are used by Underwriters Laboratories UL as guidelines for the testing and listing of electrical enclosures and are defined in the UL 50E standard.

It should be noted that there is no direct conversion between IP and UL protection types. However, the level of protection they offer is comparable, as the following overview shows with regard to protection against water and dust.
In addition, NEMA also includes certain environmental conditions in accordance with the "NEMA 250" test specifications and - unlike the IP test procedures in accordance with EN 60529 - takes into account the corrosion resistance of the enclosure, for example. Ageing, oil and coolant resistance, icing and mechanical effects are also taken into account.

These differences clearly show that different equipment is required for the UL 50E test procedure than for the IP test procedures. For example, the water tightness test requires a water pump calibrated by an accredited test laboratory which, depending on the test procedure, guarantees the required pressure output and has jet nozzles with the corresponding internal diameter.