IP21 vs IP66
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP21 and IP66 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 2 vs 6) and liquid protection (level 1 vs 6). IP21 is rated for > 12.5 mm — finger and vertically dripping water, while IP66 provides dust-tight and powerful water jets (12.5 mm nozzle).
Designed for environments requiring protection against solid objects larger than 12.5 mm and protection against vertically falling drops of water. Dripping water shall have no harmful effects., IP21 is an IEC 60529 code combining solid level 2 with liquid level 1.
IP66 is dust-tight and resists powerful water jets (12.5 mm nozzle, 100 kPa). A robust outdoor rating for equipment exposed to heavy rain, storms, or directed high-pressure hosing (but not high-pressure washdown).
Detailed comparison
The stronger rating on each row is highlighted in emerald.
Solid protection (first digit)
IP21
2 — > 12.5 mm — Finger
IP66
6 — Dust-Tight
Liquid protection (second digit)
IP21
1 — Vertically Dripping Water
IP66
6 — Powerful Water Jets (12.5 mm nozzle)
Dust-tight
IP21
No
IP66
Yes
Water-jet resistant
IP21
No
IP66
Yes
Submersible
IP21
No
IP66
No
Outdoor suitable
IP21
No
IP66
Yes
The exact difference (IP21 vs IP66)
Solid protection
IP21
Level 2 — > 12.5 mm — Finger
IP66
Level 6 — Dust-Tight
IP21 provides "> 12.5 mm — Finger" (level 2), while IP66 provides "Dust-Tight" (level 6). IP66 is 4 levels higher.
Liquid protection
IP21
Level 1 — Vertically Dripping Water
IP66
Level 6 — Powerful Water Jets (12.5 mm nozzle)
IP21 handles 0.1 mm/min drip rate (Vertically Dripping Water), while IP66 handles 100 kPa (Powerful Water Jets (12.5 mm nozzle)). IP66 provides 5 levels more liquid protection.
NEMA equivalents
Recommendation
IP66 offers higher overall protection than IP21. Choose IP66 for harsher environments; IP21 may suffice for milder conditions and can be more cost-effective.