NEMA and IP Ratings: How to Understand Them and Choose the Right Sensor

This rating is manufacturer-specified, often stemming from a customer request. While IP68 products must also meet the requirements of IP67, the manufacturer decides what further ingress protection is required. The manufacturer also determines if the enclosure needs to be tested to withstand temperature constraints. Be sure to check with each manufacturer of an IP68-rated product to understand their test procedure for this rating.

The IP ratings indicate whether a sensor enclosure meets the ingress protection required of the particular rating. IP and NEMA ratings do not describe a sensor’s ability to function.

However, IP68 is a manufacturer-specified test, meant to be more stringent than IP67. Each manufacturer sets their own maximum submersion time and depth, depending on the application. Sometimes moisture may condense inside the enclosure, but this is not considered water ingress for testing purposes.

The IP rating only indicates how well the sensor’s enclosure protects against ingress of solid particles and liquids. The IP rating does not tell you how the sensor enclosure might hold up in a corrosive environment. IP ratings also don’t take humidity into account, so sometimes humid air can find its way into an enclosure and cause condensation if there are drastic temperature changes. In turn, this condensation may cause erratic sensor operation.

The Banner test for IP68 involves first testing the enclosure to meet IP67. There are also rigorous temperature and submersion tests after which the sensor must still be able to function. Banner-defined IP68 means that a sensor should not leak for a minimum of 24 hours of continuous submersion at two meters of water.

Not necessarily. IP69K sensors are able to withstand a high-pressure water jet, but may not be able to withstand submersion. IP69K sensors do not have to automatically comply with IP67 and IP68 ratings, but all Banner products which are IP69K rated are tested to at least one meter submergence in water.

With IP69K, we spray a sensor with water at 1500 psi at four inches to six inches from the sensor. The water used is at 176 °F and is blasted at the rotating sensor for 30 seconds from four angles (120 seconds in total). The water has a flow rate of four gallons per minute. After testing, the sensor is inspected to determine if there is any water inside. An IP69K-rated sensor should continue to function even after exposure to high-pressure, high-temperature water jets.

No, there is a high-pressure washdown NEMA rating. The NEMA ICS 5 rating, also known as PW 12, specifies that a sensor must withstand a water spray of one gallon/minute at 1200 psi and 140 °F. A sensor with this rating is usually adequate for a variety of industrial environments that use high pressure washdown cleaning. The PW 12 designation is usually added to another NEMA rating, for example NEMA 6 PW 12.

Most IP and NEMA tests are conducted at 23 °C (room temperature). As it refers to use in washdown environments, IP69K has a specific temperature requirement of an enclosure resisting high-pressure, 80 °C water jets. IP68 is specified by an agreement between the manufacturer or the customer and as such, Banner will determine how to test a sensor for this rating. For example, a Banner IP68 test involves a water soak at both 70 °C and –25 °C for 24 hours, with a minimum of one hour at each temperature. 

IP ratings indicate protection against outside elements and don’t specifically take hazardous environments into account. NEMA ratings, on the other hand, have four specific ratings for enclosures used in hazardous areas: Types 7, 8, 9, and 10.

Though there seems to be a lot that goes into determining which sensor enclosure rating you need, it’s not complicated. For many applications, you just have to know what environmental situations you need to protect against. Make a comprehensive assessment, then choose the ratings that offer a level of protection sufficient for that environment. Contact a Banner engineer if you have any questions, and they’ll help you find a sensor solution with the proper level of protection to safely satisfy your application.