The Basics of IP Ratings and IP Rated Connectors

Everybody knows someone who has accidentally spilled liquid on their smartphone or dropped the device in water. Studies suggest that about 20% of phones may suffer this fate, with some models now built to resist immersion in shallow water for short periods of time.

Demand is growing for new types of portable and wearable electronics and many of these devices (along with IoT devices such as outdoor environmental sensors and industrial process monitors) need protection against unintentional or unavoidable contact with moisture. Risks include exposure to rainwater, liquid splashes, or even full immersion for indeterminate periods. Ingress of dust or particles may also prevent correct operation and compromise reliability.

Effective protection against these hazards needs to be designed-in at an early stage. Potential entry points for moisture or particles include the seams or joints of the enclosure and any exposed connection points for attaching cables or external devices. When choosing the enclosure and connectors, designers can assess the extent of the protection provided by looking at the stated Ingress Protection (IP) rating.

What is IP Rating?

IP rating codes are internationally recognized and follow a standardized scale defined in IEC 60529 and its national or regional equivalents such as ANSI 60529 in the US and EN 60529 in Europe. The code contains the IP prefix followed by two numbers. The first number describes resistance to ingress of solids such as dust or other small particles, while the second number expresses protection against liquids.

IP67 = Solids Rating (First Number)

IP67 = Liquids Rating (Second Number)

Basic breakdown of IP rating classifications

How are the IP Rating Numbers Defined?

The following table describes the extent of the ingress protection implied by each number. For example, IP67 rated means the part is dust-tight and will survive full immersion in water up to 1 meter deep for up to 30 minutes.

Choosing IP Rated Connectors

When choosing components such as exposed external connectors that could allow water or particles to enter the equipment, selected parts should have a high enough IP rating to provide the required minimum protection based on the application’s intended use.

Some applications may require the combination of a connector and plug that are sealed when mated. These are often needed for industrial cable-to-cable connections used to link controllers or modules in environments where penetrating dust or moisture can disrupt signals, corrode contacts, or damage components such as transmitters or power sources. These fully sealed cable connections can resist water ingress even if exposed to high-pressure water – for example if nearby equipment is cleaned with a pressure washer – or if they become fully immersed.


Example of a fully IP rated receptacle and plug connection with locking/sealing interface


On the other hand, where a device has external ports such as a micro USB port, headphone socket, or dc power input, IP rated connectors may be needed to protect internal circuitry when no external cables or equipment are connected. A high enough IP rating enables designers to ensure their device enclosure is fully sealed and protected against dirt and moisture. This type of usage is more prevalent than those that require permanent waterproofing when mated and is expanding much faster thanks to the rapidly growing market demands for portable devices.

It is important to note that connectors, which are independently IP rated, are not designed to remain waterproof when a plug is inserted, even if the plug is IP rated as well. An additional locking and sealing mechanism would be required to provide the necessary ingress protection at the interface between the plug and receptacle, similar to the screw terminal interface shown in the image above.


Liquid and dust can still penetrate mating connection without additional sealing mechanism


Air Electro IP Rated Connectors

Air Electro has a portfolio of IP67, 68 and 69 rated connectors including Power and Control connectorsUSB Micro B and Type C receptacles that conform to either USB 2.0 or USB 3.1 Gen 2, as well as fully submergible deep sea connection solutions like the Souriau SWIM series. These solutions can prevent dust and high-pressure water from passing through to the device in an unconnected state. Sealing is typically achieved using rubber parts such as a custom-shaped gasket or o-ring positioned to provide effective sealing.

The growing use of portable devices has led to the need for more rugged products and components. Air Electro’s IP rated connectors provide extra protection from dust and moisture, giving designers added flexibility in applications that must remain sealed from outside contaminants.

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