IP ratings (IEC 60529)

An IP code (ingress protection) says how well an enclosure keeps out solid objects and water. It is defined in IEC 60529. The code is IP, two digits, then optional letters: in IP65 the 6 is for solids and the 5 is for water. An X in place of a digit means that part was not tested, as in IPX7.

First digit: solids and dust

Digit	Protected against	In practice
0	Not protected	No protection against touch or solid objects.
1	Objects of 50 mm and up	Keeps out the back of a hand; no protection against deliberate contact.
2	Objects of 12.5 mm and up	Keeps out fingers.
3	Objects of 2.5 mm and up	Keeps out tools and thick wires.
4	Objects of 1 mm and up	Keeps out most wires and small screws.
5	Dust-protected	Some dust may get in, but not enough to stop the equipment working.
6	Dust-tight	No dust gets in.

Second digit: water

Digit	Protected against	In practice
0	Not protected	No protection against water.
1	Dripping water	Drops falling straight down do no harm.
2	Dripping water, tilted 15°	Falling drops do no harm with the enclosure tilted up to 15°.
3	Spraying water	Spray up to 60° from vertical does no harm.
4	Splashing water	Splashes from any direction do no harm.
5	Water jets	Jets from a 6.3 mm nozzle, from any direction, do no harm.
6	Powerful water jets	Powerful jets from a 12.5 mm nozzle do no harm.
7	Temporary immersion	Short immersion, tested between 0.15 m and 1 m depth.
8	Continuous immersion	Longer or deeper immersion, on conditions agreed with the manufacturer.
9	High-pressure, high-temperature jets	Close-range hot water jets, as in wash-down cleaning. Added in amendment 2 (2013).

Up to 6 the water digits build on each other. From 7 they don't: immersion (7, 8) is a different test from jets, so a motor that must survive both is marked twice, for example IP65/IP67.

IP69K is not an IEC 60529 code. The K suffix comes from ISO 20653 (road vehicles, replacing DIN 40050-9), where 9K means high-pressure, high-temperature wash-down. You see it on food-grade and wash-down motors.

Optional letters

An additional letter after the digits says how well people are kept away from hazardous parts, when that is better than the first digit says:

Letter	Meaning
A	Back of hand (50 mm sphere) cannot reach hazardous parts.
B	Finger (12 mm, 80 mm long) cannot reach hazardous parts.
C	Tool (2.5 mm, 100 mm long) cannot reach hazardous parts.
D	Wire (1 mm, 100 mm long) cannot reach hazardous parts.

A supplementary letter at the end adds information:

Letter	Meaning
H	High-voltage apparatus.
M	Water test done with the moving parts (e.g. the rotor) running.
S	Water test done with the moving parts stationary.
W	Suitable for stated weather conditions, with extra protective measures.

Common motor ratings

Code	What it means
IP54	Dust-protected (5) and splash-proof from any direction (4). Fine indoors, not for hosing down.
IP65	Dust-tight (6) and resists water jets (5). Survives a hose-down, not immersion.
IP67	Dust-tight (6) and survives temporary immersion up to 1 m (7). Not tested for jets unless also marked IP65 or IP66.

Read the footnotes too: on a servo motor the rating can depend on the connectors being mated or on an optional shaft seal.

Summarised from the standard named above. For a design decision, check the motor maker's datasheet and the current edition of the standard. More datasheet reference pages.