TDK-Lambda Americas Blog

What is a Power Supply’s IP Rating?

Ingress Protection (IP) Safety Certification Application Information

December 5, 2011

The popularity of outdoor electronics has brought the subject of a power supply’s IP rating from almost obscurity to an everyday question. I frequently get asked about it by our sales people now, so I thought it would be nice subject to cover in our blog. In researching this blog article I even discovered something new myself.

IP is the acronym for Ingress Protection, and for power supplies the IP Rating Code consists of the letters “IP” and two numbers as defined below.

The first number indicates the power supply’s protection level against the ingress of solid objects or dust.

First Number for Solids or Dust
Level Size of Object Type of Object
X Test not made Test not made
0 N/A No protection
1 50mm or larger Large body surfaces*
2 12.5mm or larger Fingers
3 2.5mm or larger Small tools
4 1mm or larger Screws
5 Dust protected -
6 Dust tight -
* Does not include deliberate body part contact


The second number indicates the power supply’s protection against the ingress of water or other liquids.

Second Number for Liquids
Level Protected against
X Test not made
0 No protection
1 Water dripping vertically
2 Water dripping at an angle
3 Spray water up to 60° from vertical
4 Splashing water from any angle
5 Low pressure water jets
6 Strong spray jets, heavy seas (ship decks)
7 Temporary immersion (up to 1m)
8 Permanent immersion (deeper than 1m)


Most recently LED power supplies, or drivers as they are often referred to, have ratings of IP66 or higher. Referring to the charts above, an IP66 rating means the unit has ingress protection from Dust and Strong Jet Sprays of Water.

These IP ratings also apply to the end system of course, and many of our customers utilize a NEMA enclosure to make their products meet a higher rating.

The IP rating is usually stated in the Safety Certification reports and the installation manual.

Power Guy