An additional number has sometimes been used to specify the resistance of equipment to mechanical impact. This mechanical impact is identified by the energy needed to qualify a specified resistance level, which is measured in joules (J). This has now been superseded by the separate 'IK code' specified in EN 62262.
Although dropped from the 3rd edition of IEC 60529 onwards, and not present in the EN version, older enclosure specifications will sometimes be seen with an optional third IP digit denoting impact resistance. Newer products are likely to be given an IK rating instead. However there is not an exact correspondence of values between the old and new standards.
Dropped IP level |
Impact energy |
Equivalent drop mass and height |
0 |
— |
— |
1 |
0.225 J |
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 |
IK number |
Impact energy (joules) |
Equivalent impact |
00 |
Unprotected |
No test |
01 |
0.15 |
Drop of 200 g object from 7.5 cm height |
02 |
0.2 |
Drop of 200 g object from 10 cm height |
03 |
0.35 |
Drop of 200 g object from 17.5 cm height |
04 |
0.5 |
Drop of 200 g object from 25 cm height |
05 |
0.7 |
Drop of 200 g object from 35 cm height |
06 |
1 |
Drop of 500 g object from 20 cm height |
07 |
2 |
Drop of 500 g object from 40 cm height |
08 |
5 |
Drop of 1.7 kg object from 29.5 cm height |
09 |
10 |
Drop of 5 kg object from 20 cm height |
10 |
20 |
Drop of 5 kg object from 40 cm height |