What Is the Best IP Waterproof Rating?
When most people buy a new smartphone, they check its specs to find out if it’s durable enough to fit their lifestyle. One common thing that smartphone buyers now look for is an IP67 or IP68 rating, which indicates substantial protection against your smartphone’s natural enemy: water.
The IP rating system applies to far more than consumer device protection, however. IP ratings are also widely used for electrical and electronics enclosures in industries like manufacturing, construction, agriculture, energy and many others. Hongfa sells a huge variety of IP rated enclosures, and that means we hear the question fairly often: What is the best IP waterproof rating?
We’ll talk about that question below, along with some other key facts — such as how to figure out which IP rating you need, as well as where to find IP rated enclosures with the right ratings. To get started, let’s quickly review the IP rating system.
What Are IP Ratings?
Ingress protection (IP) ratings are an international standard for rating how well protective enclosures perform against environmental hazards. Device designers around the world use the IP rating system to easily compare protective performance between different enclosure models and specify requirements for enclosures in a project.
IP ratings are based on a section of the International Electrotechnical Commission code, and they’re the major standard for protective enclosures in the European market. They’re also common in the United States, where they exist alongside the NEMA rating scale.
The IP rating scale evaluates two specific factors: protection against solids (such as objects, dirt or sand) and protection against water (such as rain, snow, hose spray or submersion).
Each rating is made of two digits.
Examples: IP55, IP68
The first number measures the enclosure’s resistance to solids, while the second refers to its resistance to water.
Both ratings are ascending numerical scales — 1 through 6 for dust protection and 1 through 8 for water protection.
In this guide, we’ll mostly be concerned with what IP ratings can tell you about waterproofing. For a full introduction to how IP ratings work, including how to make sure your IP enclosure is dustproof, see our ultimate guide to IP ratings!
IP68: The Top IP Waterproof Rating
In terms of which IP rating offers the most waterproof protection, there’s a clear answer: IP68 is the best commonly available waterproof IP rating. Technically, the first digit doesn’t matter if we’re only discussing waterproofing. Since 8 is the highest number on the IP water rating scale, any IP enclosure with a rating ending in 8 offers the best possible waterproof protection. However, IP68 is usually acknowledged as the most protective IP waterproof rating in common use.
Here’s the official meaning of the number 8 in an IP rating:
“Ingress of water causing harmful effects shall not be possible when the enclosure is continuously immersed in water under conditions which shall be agreed between manufacturer and user but which are more severe than for numeral 7.”
If that standard sounds slightly vague, don’t worry — we’ll explain why in just a minute. Right now, understand that this means that an IPx8 rating means the enclosure can protect a device against prolonged submersion in water. The IPx8 standard also specifies that the enclosure also has to keep water out at a depth greater than one meter.
P68 is the rating that many device designers look for when specifying a waterproof electrical box. Since an IP68 rated enclosure is also dust-tight, an IP68 enclosure provides the best value for most applications, making it easy to keep sensitive devices safe from dust and other particulates, as well as water.
Technically, one higher rating than IP68 does exist: IP69K. An IP69K enclosure adds protection against high temperature and high pressure water jets. However, IP69K enclosures aren’t widely used outside of a few specific applications. In most cases, IP68 is the rating you’ll want to look for if you need an ultra-durable waterproof enclosure.
How Protective Is an IP68 Rating?
We’ve discussed how IP68 enclosures are at the top of the IP rating scale, but how does that protection actually work in practice? We cover this topic in depth (no pun intended) in our TechTalk article, What is IP68?, but we’ll discuss some of the essentials in the next sections.
The short version is that device designers who need IP68 enclosures (or any IPx8 enclosure) always need to check the actual protective specs of the enclosure they’re choosing. Because IP68 represents the top of the rating system, it encompasses enclosures with a wide variety of specs so long as they meet its minimum requirements. This is why the wording of the IPx8 standard is so non-specific.
With that in mind, it’s important to learn about how to access UL testing data for an IP rated enclosure. UL is an independent lab company that tests IP rated enclosures to verify their compliance with IEC standards. Any IP rated enclosure you purchase should have its rating tested and verified by UL, which is why Hongfa provides UL reference numbers for all of our IP and NEMA enclosure models. Using the UL reference number and UL’s Product iQ tool, it’s simple to find detailed info to verify an enclosure’s IP rating and examine its specs.
With that in mind, let’s examine a few more of the key factors that it can be important to look for when evaluating an IP68 (or any IPx8) rated enclosure.
Determining the Rated Depth and Time of Your IP68 Enclosure
According to the standard, an IP68 enclosure should protect against water ingress during submersion at depths of one meter or more. However, there’s no universal requirement for exactly how deep an IP68 enclosure should be rated for.
Instead, the standard only says that the conditions “shall be agreed upon between manufacturer and user.” Most common IP68 applications don’t involve submersion in more than a few feet of water. However, some specialty applications may require enclosures rated for much deeper submersion. That means an important part of shopping for an IP68 enclosure is checking the manufacturer’s UL testing data to determine the enclosure’s rated depth.
Be sure to also check the duration of submersion that the enclosure has been tested for. While IPx7 enclosures are specifically rated for a submersion duration of 30 minutes, IP68 enclosures can be rated for any length of submersion greater than that. Submersion time is thus also a factor to look for when evaluating the specific performance of an IP68 enclosure.
Other Things to Know About IP68 Enclosures
In some cases, IP68 enclosures may also allow a small amount of water ingress if testing authorities consider the quantity of water to be non-hazardous to the device. Again, however, there’s no single unified standard to determine what counts as non-hazardous, so it’s always better to check testing data and communicate with the manufacturer regarding the specific water ingress levels.
The IP68 rating also doesn’t rate protection against any liquids other than water. Soap, grease, oil and other liquids aren’t part of the IP rating standard, so be careful to verify that the enclosure model you’re considering offers protection against other liquids if your application requires it. This also applies to factors such as corrosion resistance, which we’ll discuss in just a minute.
Is There a NEMA Equivalent to IP68?
Finally, you might also be wondering how an IP68 rating compares to the NEMA enclosure ratings that are common in the North American market. While converting IP ratings to NEMA ratings can be tricky, an IP68 rating is generally equivalent to a NEMA 6P. Both of these ratings represent the very highest levels of waterproof protection that you’ll find in an electrical enclosure.
Remember, though, that NEMA ratings can’t always be converted back into IP ratings. Some factors of the NEMA scale, such as corrosion resistance, aren’t included on the IP scale. If these factors are important for your application, you’ll need to look at enclosures with additional NEMA ratings, such as NEMA 4X enclosures.
