Hello Sam,
Thanks for your enquiry! 
The enclosure ratings specified by the U.S. National Electrical Manufacturers Association (NEMA) define what environmental conditions a given enclosure can withstand and its sealing effectiveness. NEMA 4X enclosures are suitable for outdoor and indoor applications that require a level of protection against corrosion, dust, rain, dripping and light splashing of liquids, as well as external ice formation.
These features make NEMA 4X standards equivalent to U.S. Underwriters Laboratories (UL) 50 Type 4X ratings and comparable to VDE 0470 (British BS EN 60529, European EN 60529) Ingress Protection (IP) 66 rating, which ensures resistance against dust and high-pressure jets.
Spelsberg offers a wide range of certified 4X and IP66-rated enclosures to effectively protect electrical equipment in harsh conditions. For example, our GEOS series is designed to withstand corrosion and prevent the ingress of dust, moisture, rain and liquid dripping. You can learn more about Spelsberg’s GEOS range here: https://www.spelsberg.com/GEOS-Industrial-and-Outdoor-Enclosures/
If off-the-shelf solutions do not fully address your needs, we are able to create fully customised enclosures that suit your intended application. To help you get what you need as quickly as possible, we can deliver samples to our UK customers within 24 hours. For additional information on Spelsberg’s customisation capabilities, visit: https://www.spelsberg.co.uk/solutions/customising/overview/https://www.spelsberg.co.uk/customising/ 
If you have additional questions or would like a bespoke enclosure, please feel free to send me a private message to discuss the requirements that your enclosure needs to meet.
To read more about NEMA and IP equivalency as well as assembly and installation recommendations from Spelsberg, click here.
If you have anymore questions, please dont hesitate to get in touch!
Chris