IP ratings in RF connector applications

Most engineers (including this author) have at one time or another been accused of over-designing or over-engineering a product.  It is often claimed that tolerances that are unnecessarily tight, or a requirement is impossible to meet, or an electrical spec can't be met.  Whether its the manufacturing engineer, the purchasing manager, or a supplier, someone will be sure to give you an earful about how you don't need something that performs that well.  One such topic that runs across my desk fairly often is the IP rating of connectors.

Lets start with some definitions!  Since ratings less than IP54 become meaningless in the connector world, lets start there and work our way up the most common ratings.  IP67 and IP68 are the two most common seen in the marketplace.  IP ratings are split between 2 numbers that reflect the products ability to resist solid particles and liquid particles.  The first number represents the solids and second number represents the liquids.

IP54: 5 = dust protected,  4 = splash proof

IP67: 6 = dust sealed, 7 = submersion to 1 meter for 30 minutes

IP68: 6 = dust sealed, 8 = submersion to customer specification

For the full breakdown please see the Connex page.


The critical take-away from this brief explanation is to show that the rating can be vague, so a full understanding of the connector is critical to not over-designing your application.  In most applications when a customer purchases an IP67 connector for a non-submerged application, IP54 would achieve their goals.  If you need your panel sealed - is the connector IP67 rated to the panel or just through the interface? Is it only sealed to the panel and not through the interface?  Is it sealed in the mated condition only?  In all cases, a connector may be labeled as IP67, even though it may seem that it is a misrepresentation of the product.

Is IP68 better than IP67?  Well, it depends - is the application fully submerged for longer than 30 minutes and at depths more than 1m?  If not, then the two ratings are largely indistinguishable.  Just because 8 is a higher number than 7, does not mean that it is "better" or more appropriate for the application.  Furthermore, IP68 is achieved to a customer specification - there is no industry standard.  Be sure to investigate the actual test (or equivalence of the test done) to determine the capabilities of the connector.  IP68 could mean that the connector is capable of 1.1m for 31 minutes or it's capable of 100m for 10 years.  Those are wildly different, but achieve the same rating.  This is a bit of trickery that marketers love to exploit.  Conversely, a well designed IP67 rated connector may meet the customer’s IP68 requirements, but because it has not been tested to that customer's specification, it has not been granted the IP68 rating.

For a comprehensive list of our IP67 parts available through distribution, please see our Digi-Key page.

Amphenol RF is your source for RF interconnect information, please contact us with any questions you may have!