The term "IP Rated" is used to evaluate electronic equipment for their resistance to dust and water.  IP stands for Ingress Protection and this system is one that has been defined by the International Electrotechnical Commission (IEC) standard IEC 60529. 

The IP rating is crucial because it gives customers purchasing the products a clear, objective measure of a device's resilience, helping them to choose the right product for their needs.

Understanding the IP Code Structure

An IP rating will always start with the letters "IP" followed by two numbers. IP67 is an example of this.

First Digit: Protection Against Solids (Particulate Ingress)

The first digit gives us the level of protection against solid objects getting into the light.  This ranges from large body parts down to microscopic dust. The scale goes from 0 (no protection) to 6 (total dust ingress protection).

Second Digit: Protection Against Liquids (Moisture Ingress)

The second digit indicates the level of protection against various forms of moisture such as dripping water ranging up to powerful jets or long periods of being submerged in water. This scale typically goes from 0 (no protection) to 9 (high-pressure, high-temperature jets).

Please be advised that if the letter “X” is used in place of one of the numerical digits it means that the fixture was not specifically tested to give it a rating for this or that the data for this classification is unavailable.

What IP Rating is Waterproof?

In regards to electronics the phrase “waterproof” is used fairly loosely.  It would be more accurate to describe any electronic objects that have this description as water resistant because it is impossible for a device to be 100% waterproof for an indefinite amount of time.  Choosing an item that has an IP rating of IPX7 or IPX8 would be the best choice for choosing a device which will be highly resistant against water ingress.  Waterproof seals can also degrade over time reducing the level of protection.  You should consult the manufacturer’s guidelines if you have any doubts or concerns.

Summary:

IP ratings are given to light fittings so that the user can know how much protection they offer against solid objects getting into the fixture including dust and how much protection they will have against water as well.  For the best protection about both of these things it is highly recommended that you choose an IP67 or IP68 rated item.