IP Ratings

At the time of writing this website is 20 months old and has just over 400 pages, and so I can't think why I haven't put this on before now. I blame it on the fact that I'm getting old and yes please Vicar I would like a pilchard sandwich.


Sorry, where was I? Oh yes, IP ratings. IP stands for ingress protection, and or those of you who don't know ingress means a way in. Egress means a way out. Knowing that you can be a proper swot and baffle people who come to your house or place of work by using the words ingress and egress.Or perhaps not  though  as pretty soon people will stop coming to your house and you'll probably get sacked. Or at least publicly debagged.


So, ingress protection then. As the name implies, the protection is against things getting into the electronic or electrical system and it's done by means of an enclosure which is usually a plastic or metal box.


Commonly you will see the letters IP followed by two digits:  IP55,  IP65,  IP 68  for three examples. If you've ever wondered what they mean, wonder no more.


The first digit after IP is the protection against solid particles; this can be anything from hands to little bits of dust.


0 means no protection whatsoever, that is the device is not enclosed. You'll not see that in consumer devices.


1 means protected against any object greater than 50 mm. You'd probably get a finger in there, but not the back of your hand. You'd certainly be able to shove a screwdriver or small knife in there.


2 means protected against any object greater than 12.5 mm. An adult won't be able to get a finger in there unless they have very slim fingers. A child will though.


3 means protected against any object greater than 2.5 mm. You shouldn't be able to get any part of your anatomy in there, and thick wires and tools are excluded too.


4 means protected against any object greater than 1 mm. Most things that can conduct will not go in there. But heat can still get out if needs be.


5 means dust protected. It's not entire, but all but the smallest particles will be prevented. Complete protection against bodily contact is achieved at 5.


6 means the unit is entirely enclosed. Nothing gets in, nothing gets out. It's not usual to see this in domestic terms, but you might in industry.


The second digit after IP is the protection against water. It's far more insidious than is dust and can get anywhere.


0 once again means the electrical/electronic parts are not protected against water.


1 means that vertically falling water cannot get in.


2 means that water falling at an angle not greater than 15 degrees can't get in.


3 means that water falling as a spray at any angle up to 60° from the vertical can't get in.


4 means that  water splashing against the enclosure from any direction can't get in.


5 means that  water projected by a 6.3 mm nozzle (the test size) against the enclosure from any direction can't get in.


6 means that water projected by a 12.5mm nozzle against the enclosure from any direction can't get in.


7 means that  no igress of water is possible even when submerged up to a depth of 1m.


8 means suitable for permanent immersion beyond 1m to a depth specified by manufacturer.



All of these ratings are defined in IEC standard 60529 and to get the full text you have to have a license; I don't know why either but they don't publish it for non-licensees. In domestic terms, IP 22 is the minimum standard for indoor use to which a product must conform. Electrical sockets outdoors are supposed to be at least IP54  but if they're to be used anywhere dusty then IP66 is better.


Sometimes there is a third digit, although it's no longer required you do see them. The third digit denotes impact resistance.



1    0.225 J     or      150 g dropped from 15 cm


2    0.375 J               250 g dropped from 15 cm


3    0.5 J                    250 g dropped from 20 cm


5    2 J                       500 g dropped from 40 cm


7   6 J                       1.5 kg dropped from 40 cm


9  20 J                     5.0 kg dropped from 40 cm



The Americans of course use their own codes, the NEMA codes. A guide to the differences is;



IP56 is NEMA 4, or NEMA 4x  if there are anti corrosion measures in place.


IP65 is NEMA 6


IP52 is NEMA 12


IP54 is NEMA 13


Ian Lang May 2012