I'm trying to replace connections between a trunk cable and drop cables in a DeviceNet system. The system is in a high humidity environment, so the current clamps used now are not holding up with the harsh conditions. The plan is to replace the cable with a round cable with t-port taps. The taps are IP67 rating, which can handle full submersion in water for 30 mins. I'm wondering though if it will still hold up in the high humidity environment which is constant. My question is asking if IP ratings correlate with a products ability to tolerate humidity.
I'm a little late to the party here, but it's worth mentioning (if only for anyone that finds this in the future) that IP levels don't stack beyond IPX6. Therefore something that's IP67 doesn't necessarily meet the criteria for water ingress levels 1-6. The same goes for IP68. Another note of worth is that IP67 & IP68 allow for some ingress of water, but only as long as it doesn't happen in harmful quantities.
The answer is really dependant on what the behaviour of the high humidity in the high humidity environment is. If you want to use IP67 parts in that situation, you really need them to be IP66/IP67 dual rated. (IP66 being a catch-all for IPX1 to IPX6)
I don't currently have access to the IEC 60529 standard, so my references are based around Wikipedia under the section detailing "Second Digit: Liquid Ingress Protection", and also a scanned in copy of the Indian Standard IS/IEC 60529 (which I found via search engine) which claims to be identical to the IEC 60529 standard (which I can't verify).
IS/IEC 60529 states: "An enclosure designated with second characteristic numeral 7 or 8, only is considered unsuitable for exposure to water jets (designated by second characteristic numeral 5 or 6) and need not comply with requirements for numeral 5 or 6 unless it is dual coded as follows:". Following this statement, there is a table detailing ratings such as IPX6/IPX7 as "versatile" and ratings such as IPX7 as "restricted"
The non-cumulative IPX7 & IPX8 can also be corroborated on multiple supplier websites (such as RS Components under the section on "Weatherproof & Waterproof IP Ratings").