If you shop around for electrical enclosures, you might see something in the literature known as an IP rating. It might look like “IP65,” or have a different two-digit number on it.
What does this mean?
It’s a special rating maintained by the International Electrotechnical Commission (IEC), and it’s worth taking time to learn how these ratings work.
IP Ratings Explained
IP stands for “ingress protection.” This is a formalized rating system that explains how well an enclosure protects against ingress.
The rating starts with the letters “IP” followed by a two-digit number. The first digit expresses the foreign solid object protection while the second number denotes water protection.
The solid object ratings range from 0 to 6. A rating of 0 offers no special protection while a 6 is dust-tight.
The water scale ranges from 0 to 9. A 0 again offers no special protection, but a 9 is tested against high-pressure jets and high-temperature water. A rating of 7 is the lowest on the scale rated against total submersion.
If you want a detailed breakdown of the whole scale, you can find the IEC chart here.
What Do You Need for an Electrical Enclosure?
With that covered, what kind of rating do you need? Electrical devices need protection from water and many kinds of solid objects, so what should you look for?
That ultimately depends on the function of your enclosure, so we can break it down into a few categories.
Standard Junctions
If you’re installing an electrical box for junctions inside of a building, typically, you don’t need any IP rating at all. There’s no major concern for solid objects, dust, or water. As long as the enclosures suit the purpose they serve, they’re fine.
Outdoor Enclosures
Outdoor enclosures need more protection, and it’s common to look for IP ratings when making your selection. Typically, you want enclosures that can stand up to wind and rain. Depending on where the enclosure will live, you might need greater protection.
There is no universal answer, but in many cases, you want something in the ballpark of IP65. This can handle heavy rain in any direction, and it is dust-tight. Naturally, if you expect greater water exposure or less dust risk, you can shift your IP rating accordingly.
Specialty Enclosures
Lastly, we consider specialty enclosures. What if you’re designing an automated car wash and need enclosures that might be exposed to spraying jets and the like?
An IP rating of 69 is as high as it goes, and this will satisfy the vast majority of use cases. When in doubt, it’s a good rating to consider. Of course, it’s a matter of use cases. You can select an IP rating according to the exposure facing your electrical enclosure. If you need more water protection, move up the scale. The same goes for foreign solid objects. If you don’t need as much protection, you can typically save money by moving down on the rating scale.
That’s really all you need to know. There is no single IP rating that is optimized for all jobs, but there is a best rating for each job. Think it through, and you’ll get it right.
