Ingress Protection (IP) Ratings, IP Codes and Standards

What is the meaning of Ingress Protection?
If a liquid and/or solid particle enters into electrical equipment it may not only be harmful to the equipment, it may also be dangerous to the operator. The degree to which the electrical equipment prevents the entry, i.e. ingress, of liquids and solids is known as its ingress protection rating. Therefore when buying electrical equipment whether it be a motor, a transmitter, a switch, or a warning beacon it is essential to know what degree of ingress protection the item offers.

Ingress Protection Terminology
The acronym IP is very commonly used for ingress protection. And as can be seen in the IP protection tables and charts below, different degrees of protection are given ratings - and these are variously referred to as IP ratings, IP codes, IP classes, IP numbers or even IP grades. They all mean the same.
In the North America the NEMA classification is used for ingress protection and occasionally reference is made to an instrument's nema number, or nema rating.

What are the Ingress Protection (IP) Standards?
The applicable European standards for ingress protection are:
- BS EN 60529:1992 Specification of Degrees of Protection Provided by Enclosures
- IEC ( International Electrotechnical Commission) 60529 Specification of Degrees of Protection Provided by Enclosures.
In the USA, the National Electrical Manufacturers Association (NEMA) defines enclosure types in NEMA standard number 250. NEMA is a US trade association representing the interests of electroindustry manufacturers of products used in the generation, transmission and distribution, control, and end-use of electricity.
The International Standards Organisation publish ISO 20653. This standard applies to degrees of protection (IP code) provided by enclosures of the electrical equipment of road vehicles so is not discussed further on this page.



So how is Ingress Protection quoted?
An "IP" number, or as it is commonly known, an IP rating is used to specify the environmental protection offered. The IP rating is composed of two numbers, the first referring to the protection against solid object ingress and the second against liquid ingress. The higher the number the better the protection.

How is Ingress Protection Marking shown?
IP ratings are shown by the use of letters and numbers e.g IP54, or IP65C. Hyphens are not used in IP codes, therefore IP-35 is written wrongly. The IP Code Breakdown table below shows how ingress protection codes are made up:
ingress protection markings

What do the IP Numbers Mean?
The Ingress Protection table below shows the degree of protection that corresponds to the two numerals used in an IP protection rating.
Using this IP rating chart we can answer questions like
- What does IP54 mean? This means the equipment is protected against dust, and water sprayed from all directions.
- Is IP67 waterproof? In this case, the second numeral tells us that the instrument is protected against immersion in liquid up to 1m depth. So, yes, fairly waterproof.
IP ratings chart


How does the IP and NEMA systems compare?
The IEC and NEMA degrees of protection can not be fully compared as equivalent ratings. The NEMA Standard includes tests for environmental conditions such as mechanical damage, corrosion, rusting, ice formation, etc. However the following ip vs nema ratings table can be used as a guide:



Technical Library

The following pages on Control and give more detail on other environmental considerations when specifying instruments, junction boxes and wiring enclosures:


Further Reading

For those who want to delve further into choosing electrical components and their installation, then the following books will be of interest: