An Ingress Protection Rating is given to a garden lighting product to show its resistance to entry by physical objects and particles in the atmosphere and its resistance to water entering the enclosure or housing. It consists of two digits after the capital letters “IP” – the first digit is resistance to objects and particles and the second digit shows the resistance to water.
The first digit provides a measure of protection against solids – how dust or insect proof the product is:
4: Resistance to foreign bodies down to 1mm- this is the minimum for an exterior fitting in order to keep insects out of the live part areas.
5: General proof against dust and contact.
6: Completely dust-proof.
The second digit measures protection against liquids – in practice this means that lights are weatherproof enough for outdoor use with a minimum rating of 4. Ratings of 5 and 6 means they are OK in areas where you are using a hosepipe (but not pointing a pressure washer directly at the light!). 7 is where lights start to become more than weatherproof – they can be regarded as waterproof for limited immersion in water – this rating was originally for marine fittings as a ship’s deck rolled into a wave. Only the 8 rating means the light is waterproof for use in ponds, bog gardens or riverside gardens prone to flooding. So if your lawn becomes very soggy for a while after heavy rain, make sure recessed lights are IP68 rated or provide drainage beneath and away from the underside of an IP67 light – a gravel-filled trench or tile drain along the cable route is often sufficient.
4: Splash proof
6: Pressure hose proof
7: Protection against limited submersion
8: continuous submersion
Ingress of water can still happen to IP68 lights if but this is often to do with interference, substandard installation or extreme weather conditions which is why maintenance checkups are highly recommended at least once a year.