I thought I would post up a good explanation of Ingress Protection Ratings (IP Rating). Ingress Protection (IP) ratings are developed by the European Committee for Electro Technical Standardization (CENELEC) (NEMA IEC 60529 Degrees of Protection Provided by Enclosures - IP Code), specifying the environmental protection the enclosure provides. The IP rating normally has two (or three) numbers: 1. Protection from solid objects or materials 2. Protection from liquids (water) 3. Protection against mechanical impacts (commonly omitted, the third number is not a part of IEC 60529) Example - IP Rating With the IP rating IP 54, 5 describes the level of protection from solid objects and 4 describes the level of protection from liquids. An "X" can used for one of the digits if there is only one class of protection, i.e. IPX1 which addresses protection against vertically falling drops of water e.g. condensation.. IP First number - Protection against solid objects 0 No special protection 1 Protected against solid objects up to 50 mm, e.g. accidental touch by persons hands. 2 Protected against solid objects up to 12 mm, e.g. persons fingers. 3 Protected against solid objects over 2.5 mm (tools and wires). 4 Protected against solid objects over 1 mm (tools, wires, and small wires). 5 Protected against dust limited ingress (no harmful deposit). 6 Totally protected against dust. IP Second number - Protection against liquids 0 No protection. 1 Protection against vertically falling drops of water e.g. condensation. 2 Protection against direct sprays of water up to 15o from the vertical. 3 Protected against direct sprays of water up to 60o from the vertical. 4 Protection against water sprayed from all directions - limited ingress permitted. 5 Protected against low pressure jets of water from all directions - limited ingress. 6 Protected against temporary flooding of water, e.g. for use on ship decks - limited ingress permitted. 7 Protected against the effect of immersion between 15 cm and 1 m. 8 Protects against long periods of immersion under pressure. In my experience, most fixture failures are due to moisture and insects getting inside the body of the fixture. Moisture, even small amounts of condensation, wreak havoc on internal wire connections, sockets, and lamps. And we have all found ants, and other bugs making their home inside fixtures. By designing and building fixtures that have a high IP rating, we do away with all of this and have fixtures that stand the test of time. Obviously a lot more engineering has to go into a fixture that obtains an IP68 rating (the highest level of ingress protection) but I think this is a direction that the industry must move towards. Does it result in a more expensive product? Sure it does, but I have always maintained that one of the best ways to make more money in your operations is to install better, more expensive products.