what's the IP code of the frequency inverter?

First digit

The first digit indicates the level of protection that the enclosure provides against access to hazardous parts (e.g., electrical conductors, moving parts) and the ingress of solid foreign objects.

Level	Object size protected against	Effective against
0	—	No protection against contact and ingress of objects
1	>50mm	Any large surface of the body, such as the back of a hand, but no protection against deliberate contact with a body part
2	>12.5mm	Fingers or similar objects
3	>2.5mm	Tools, thick wires, etc.
4	>1mm	Most wires, screws, etc.
5	dust protected	Ingress of dust is not entirely prevented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment; complete protection against contact
6	dust tight	No ingress of dust; complete protection against contact

 

Second digit

Protection of the equipment inside the enclosure against harmful ingress of water.

 

Level	Protected against	Details
0	not protected	—
1	dripping water	Dripping water (vertically falling drops) shall have no harmful effect.
2	dripping water when tilted up to 15°	Vertically dripping water shall have no harmful effect when the enclosure is tilted at an angle up to 15° from its normal position.
3	spraying water	Water falling as a spray at any angle up to 60° from the vertical shall have no harmful effect.
4	splashing water	Water splashing against the enclosure from any direction shall have no harmful effect.
5	water jets	Water projected by a nozzle against enclosure from any direction shall have no harmful effects.
6	powerful water jets	Water projected in powerful jets against the enclosure from any direction shall have no harmful effects.
7	immersion up to 1 m	Ingress of water in harmful quantity shall not be possible when the enclosure is immersed in water under defined conditions of pressure and time (up to 1 m of submersion).
8	immersion beyond 1 m	The equipment is suitable for continuous immersion in water under conditions which shall be specified by the manufacturer. NOTE: Normally, this will mean that the equipment is hermetically sealed. However, with certain types of equipment, it can mean that water can enter but only in such a manner that produces no harmful effects.

Additional letters
The standard defines additional letters that can be appended to classify only the level of protection against access to hazardous parts by persons:

Level	Protected against access to hazardous parts with
A	back of hand
B	finger
C	tool
D	wire

Further letters can be appended to provide additional information related to the protection of the device:

Letter	Meaning
H	high voltage device
M	device moving during water test
S	device standing still during water test
W	weather conditions

Mechanical Impact Resistance
An additional number has sometimes been used to specify the resistance of equipment to mechanical impact. This has now been superseded by the separate IK number specified in EN50102 
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 correspondance of values between the old and new standards.

OLD 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	20.0 J	5.0 kg dropped from 40 cm

IK number	Energy	Equivalent impact
00	Non-protected	no test
01	Impact energy: 0,150 joules	Resistant against an impact from an object of 0.44lbs (200 grams) from a distance of 2.9” (7.5 cm)
02	Impact energy: 0,200 joules	Resistant against an impact from an object of 0.44lbs (200 grams) from a distance of 3.9” (10 cm)
03	Impact energy: 0,350 joules	Resistant against an impact from an object of 0.44lbs (200 grams) from a distance of 6.9” (17.5 cm)
04	Impact energy: 0,500 joules	Resistant against an impact from an object of 0.44lbs (200 grams) from a distance of 9.8” (25 cm)
05	Impact energy: 0,700 joules	Resistant against an impact from an object of 0.44lbs (200 grams) from a distance of 13.8” (35 cm)
06	Impact energy: 1,00 joules	Resistant against an impact from an object of 1.1lbs (500 grams) from a distance of 7.9” (20 cm)
07	Impact energy: 2,00 joules	Resistant against an impact from an object of 1.1lbs (500 grams) from a distance of 15.7” (40 cm)
08	Impact energy: 5,00 joules	Resistant against an impact from an object of 3.8lbs (1.7 kg) from a distance of 11.6” (29.5 cm)
09	Impact energy: 10,00 joules	Resistant against an impact from an object of 11lbs (5 kg) from a distance of 7.9” (20 cm)
10	Impact energy: 20,00 joules	Resistant against an impact from an object of 11lbs (5 kg) from a distance of 15.7” (40 cm)

 

IP69K
German standard DIN 40050-9 extends the IEC 60529 rating system described above with an IP69K rating for high-pressure, high-temperature wash-down applications.[ Such enclosures must not only be dust tight (IP6X), but also able to withstand high-pressure and steam cleaning. The test specifies a spray nozzle that is fed with 80°C water at 8–10 MPa (80–100 bar) and a flow rate of 14–16 L/min. The nozzle is held 10–15 cm from the tested device at angles of 0°, 30°, 60° and 90° for 30 s each. The test device sits on a turntable that rotates once every 12 s (5 rpm).
The IP69K test specification was initially developed for road vehicles, especially those that need regular intensive cleaning (dump trucks, cement mixers, etc), but also finds use in other areas (e.g., food industry)....
NEMA Rating
NEMA enclosure ratings have equivalent IP ingress protection ratings as follows. NEMA enclosure standards also dictate other product features not addressed by IP codes (such as submersibility, operation under icing conditions, and others).

NEMA Enclosure	IP Code
4, 4X	IP66
12	IP52
13	IP54