Ex & Degrees of Protection (IP) According to IEC 60529

Ex & degrees of Protection (IP) according to IEC 60529 in comparison to NEMA Enclosure-Types.

A system for classifying the degrees of protection provided by the enclosures of Electrical Equipment

Definition of protection includes:

• 1.    Protection of persons against access to hazardous parts of equipment inside the enclosures.
• 2.    Protection of the equipment installed  inside the enclosures, against the access (ingress) of foreign SOLID            objects
• 3.     Protection of the equipment installed inside the enclosures, against the access and the resulting harmful effects of ingress of water.

The overall object of this system is to promote uniformity in methods of describing the protection provided by the enclosures through a structured CODE, known as IP CODE or IP INDEX, which is documented and implemented through a series of tests.

The details of the protection associated with FIRST CHARACTERISTIC Numeral

The details of the protection from WATER associated with SECOND CHARACTERISTIC Numeral

Added in the IEC60529-2013 edition

..so now there are 10 (SECOND CHARACTERISTIC Numeral…. 0 to 9)

One interesting fact about IPX6  & IPX7 & IPX8 & IPX9

Enclosures for “versatile” application indicated in the last column shall meet requirements for
exposure to both water jets and temporary or continuous immersion.

Enclosures for “restricted” application indicated in the last column are considered suitable
only for the conditions to which they were tested.

The IP index is established through a series of tests , using high  precision tets devices as  documented in IEC 60529 .

For example , see the following  schematic of DRIP TEST device.  (Ref: IEC 60529)

Comparison between NEMA enclosures and IEC 60529 Complied Enclosures.

NEMA  is National Electrical Manufacturers Association  (of USA).

NEMA Publication 250-2008 defines the descriptions, applications, features ,test criteria, and design tests of all NEMA-type enclosures

Following is the list of described test in Publication 250.

• Test for Protection against Access to Hazardous Parts
• Test for Protection against Ingress of Water (Dripping and Light Splashing)
• Test for Protection against Ingress of Water (Rain)
• Test for Protection against Ingress of Solid Foreign Objects (Settling Airborne Dust, Lint, Fibers, And Flyings)

• External Icing Test
• Test for Protection against Ingress of Water (Hose down)
• Indoor Corrosion Protection (Rust-Resistance Test (24-Hour Salt Spray Test))
• Outdoor Corrosion Protection
• Corrosion Protection—Type 3X, 3RX, 3SX, 4X or 6P Enclosures
• Test for Protection against Ingress of Water (Temporary Submersion)
• Test for Protection against Ingress of Water (Prolonged Submersion)
• Oil Exclusion Test
• Gasket Tests

( This  list is shared by IEC 60529 ……….BUT  with a BIG DIFFERENCE)

The described tests are interesting due to the fact that there are following additional tests which are NOT required for  IEC rating :-

1. Corrosion test
2. Gasket aging test
3. Dust test
4. External icing test

Following Table can be used to carry out a comparison of the Type of enclosures from IP ‘s perspective.

To use this table , follow the procedure explained through an example.(Reference: IHS STANDARDS  STORE)

An IEC IP 45 Enclosure Rating is specified.   What NEMA Type Enclosures meet and exceed the IP 45 rating?

Referencing the first character, 4, in the IP rating and the row designated “IP4_” in the leftmost column in the table;

Follow the RED LINE for NEMA Types 3, 3X, 3S, 3SX, 4, 4X, 5, 6, 6P, 12, 12K, and 13 . These NEMA ratings meet and exceed the IEC protection requirements against access to hazardous parts and solid foreign objects.

Now Follow the GREEN LINE .Referencing the second character, 5, in the IP rating and the row designated “IP_5” in the rightmost column in the table;  NEMA Types 3, 3X, 3S, 3SX, 4, 4X, 6, and 6P are selected. These NEMA ratings meet and exceed the IEC requirements for protection against the ingress of water. 

As we can see that “NEMA Enclosure Type 5”  does not meet the IP 45 protection
requirements against the ingress of water. Likewise NEMA Type 12, 12K and 13 enclosures indicates that these enclosures do not meet the IP45 requirements for protection against the ingress of water.

Only Types 3, 3X, 3S, 3SX,4, 4X, 6, and 6P  could be used in an IP45 application.

(Reference : IEC 60529 Edition 2.2)

IP Perspective by Asif Mirza

(An animated Slideshow)