IP42 vs IP66
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP42 and IP66 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 4 vs 6) and liquid protection (level 2 vs 6). IP42 is rated for > 1 mm — small wires and dripping water at 15° tilt, while IP66 provides dust-tight and powerful water jets (12.5 mm nozzle).
With IP42, an enclosure receives protection against solid objects larger than 1.0 mm and protection against vertically falling drops of water when the enclosure is tilted up to 15° from its normal position.. It is an IEC 60529 ingress protection code combining first-digit (solid) level 4 with second-digit (liquid) level 2.
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)
IP42
4 — > 1 mm — Small Wires
IP66
6 — Dust-Tight
Liquid protection (second digit)
IP42
2 — Dripping Water at 15° Tilt
IP66
6 — Powerful Water Jets (12.5 mm nozzle)
Dust-tight
IP42
No
IP66
Yes
Water-jet resistant
IP42
No
IP66
Yes
Submersible
IP42
No
IP66
No
Outdoor suitable
IP42
No
IP66
Yes
The exact difference (IP42 vs IP66)
Solid protection
IP42
Level 4 — > 1 mm — Small Wires
IP66
Level 6 — Dust-Tight
IP42 provides "> 1 mm — Small Wires" (level 4), while IP66 provides "Dust-Tight" (level 6). IP66 is 2 levels higher.
Liquid protection
IP42
Level 2 — Dripping Water at 15° Tilt
IP66
Level 6 — Powerful Water Jets (12.5 mm nozzle)
IP42 handles 0.3 mm/min drip rate (Dripping Water at 15° Tilt), while IP66 handles 100 kPa (Powerful Water Jets (12.5 mm nozzle)). IP66 provides 4 levels more liquid protection.
NEMA equivalents
No direct NEMA equivalent.
Recommendation
IP66 offers higher overall protection than IP42. Choose IP66 for harsher environments; IP42 may suffice for milder conditions and can be more cost-effective.