Google search "receptacles IP54 IP67".
The IP67 receptacles are specified for outdoor areas in industrial facilities. ( simailar rating to a NEMA 6 - dusttight and water tight suitable for 1 meter submersion)
Most IP54 rated units are also IP67.
Several manufacturer's have good data on IEC receptacles: Appleton, Mennekes, Crouse-Hinds are some of the North American manufacturers. Check their websites.
I can't help on IP ratigns for indoor receptacles.