IP code, ingress protection, IP67, IP69K, environmental rating
The IP code comes from IEC 60529. The first digit runs from 0 to 6 and describes protection against solid objects, ending at 6, which is dust-tight. The second digit runs from 0 to 9K and describes protection against water, from dripping through spray and jets to immersion and high-pressure washdown.
The ratings a harness buyer meets most often are IP67, IP68 and IP69K. IP67 is dust-tight and protected against temporary immersion, typically one metre for thirty minutes. IP68 is immersion beyond that, under conditions the manufacturer defines rather than the standard. IP69K covers close-range high-pressure, high-temperature water jets, which is what a steam cleaner does to a chassis connector and what a pressure washer does to an agricultural or commercial vehicle.
Two things about IP ratings cost people money. First, the digits are not cumulative in the way they appear. IP69K does not automatically include IP68 immersion, because they are different tests against different failure mechanisms, and a connector qualified for one is not necessarily qualified for the other. The datasheet is the source, not the number.
Second, an IP rating belongs to a correctly assembled connector, not to a housing on its own. The rating holds only when the interface seal is present, every populated cavity carries the correct wire seal for the insulation diameter in use, every empty cavity carries a cavity plug, the terminals are fully seated, and the two halves are fully mated and latched. One missing plug and the rating is a number on a page.
Harness Code sources within the same environmental class when a sealed part is unavailable, and quotes the matching seals and plugs, because an IP rating that arrives incomplete is not an IP rating.
Related terms
Sealed vs unsealed connector
A sealed connector uses interface seals, wire seals and cavity plugs to keep moisture and dust out, and carries an IP rating such as IP67 or IP69K. An unsealed connector has no such protection and is used only in dry interior locations.
Wire seal and cavity plug
A wire seal is a rubber grommet crimped with the terminal that seals the gap between the wire and the connector cavity. A cavity plug seals an unused cavity. Together they give a sealed connector its rated ingress protection; a single missing seal voids it.
USCAR and LV214 (automotive connector test standards)
USCAR-2 and LV214 are the two dominant automotive connector qualification standards. USCAR-2 is the North American specification from the US Council for Automotive Research; LV214 is the German OEM specification. A substitute part has to carry the standard the drawing names.