For an IP67 rating (http://en.wikipedia.org/wiki/IP_Code), an electrical enclosure must be submerged to 1m for 30 minutes with no water ingress. A basic test setup is shown in Fig A with the EUT ( Equipment Under Test) placed at the bottom of a tank. An alternative test setup was proposed to me, as shown in Fig B. This setup has a thin pipe into a closed chamber, with the same overall depth of water. I want to say that the pressure on the EUT is the same with the two setups, but my intuition says otherwise. So, does Fig B result in the same water pressure on the EUT as Fig A? Why?