An important data sheet specification for industrial measuring instruments in general and pressure sensors in particular is the so-called ingress protection. In this context, an alledged printing error in the data sheet of the electronic pressure switch PSD-30 was already pointed out to me several times because it says that the device meets both IP65 and IP67 standards at the same time. Yes, this is absolutely true. Sounds strange? But it is true!
The explanation for this is relatively simple and straightforward considering the fact that the two IP-ratings and thus the underlying test procedures are completely different and the supposedly “higher” ingress protection IP67 does not cover or include automatically the ingress protection IP65. The PSD-30 was designed and tested for both IP-ratings. This is confirmed not only by WIKA in-house tests, but also by external tests carried out by independent test centres, for example, as part of UL approval.
The difference between IP65 and IP67
To solve the mystery of the two ratings, here is the technical explanation: According to IEC 60529, the first code number establishes protection “against ingress of solid foreign matter” and the second code number protection “against ingress of water”. Both ingress protections mentioned for the PSD-30 confirm that the PSD-30 is “dust-proof” (IP6x) equipment and protected against “splash water” (IPx5) and “temporary immersion” (IPx7). Not every device protected against immersion also withstands splash water and, vice versa, not every splash-water-protected device is also protected against immersion. A small, but important difference in some applications.
This means that the electronic pressure switch PSD-30 meets the ingress protection IP65, i.e., it is dust-proof and protected against splash water. It also meets the ingress protection IP67, i.e., it is additionally also protected against temporary immersion in water.