Here are my views when it comes to this subject and I will make a discloser now that I am currently and actively designing and selling commercial lighting systems for the farming industry and will be selling to industrial and manufacturing toward the end of this year..
When considering lighting within a machine enclosure:
Low voltage systems are a must… never use high voltage systems.
What I've found through testing:
Of the so called imported “quality” LED products
at their claimed rating, 30% have failed static testing for moisture and 45% fail during active testing (vibration with water spray and age testing).
Of the really “cheap “ products like some on the web… failure was as high as 80% static and 100% active. Again at their claimed IP rating
Now you know what I know about the imported LEDs and of coures... there are aways some exceptions.
You can, in a lot of cases, fix the moisture problems that plague these low voltage cheapo’s . Get yourself some “The Right Stuff” sealant at the auto parts store. Take the unit apart remove all of their sealant and reseal all of the joints with the Right Stuff. If any gaskets and they are made of a foam like material you will have to replace it too with a material resistant to the coolant ( Most polyester gasket materials are) Of course you need a transformer too.
Twenty or thirty bucks later and an hour of your time you might get a decent light…Oh… I almost forgot…if they have venting on the case…as some do… you can’t usually get away just with sealing the vents because the LED may over heat then start over current drawing and fail. Well... to be fair, you can add a heatsink to the unit… if you can figure where to put it.
For general information, here is a link to a simplified version of the IP rating system.
IP Rating Chart | DSMT.com