IP66 vs IP42
Head-to-head comparison of two IEC 60529 ingress protection ratings.
IP66 and IP42 are both IEC 60529 ingress protection codes, but they differ in solid-object protection (level 6 vs 4) and liquid protection (level 6 vs 2). IP66 is rated for dust-tight and powerful water jets (12.5 mm nozzle), while IP42 provides > 1 mm — small wires and dripping water at 15° tilt.
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).
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.
Detailed comparison
The stronger rating on each row is highlighted in emerald.
Solid protection (first digit)
IP66
6 — Dust-Tight
IP42
4 — > 1 mm — Small Wires
Liquid protection (second digit)
IP66
6 — Powerful Water Jets (12.5 mm nozzle)
IP42
2 — Dripping Water at 15° Tilt
Dust-tight
IP66
Yes
IP42
No
Water-jet resistant
IP66
Yes
IP42
No
Submersible
IP66
No
IP42
No
Outdoor suitable
IP66
Yes
IP42
No
The exact difference (IP66 vs IP42)
Solid protection
IP66
Level 6 — Dust-Tight
IP42
Level 4 — > 1 mm — Small Wires
IP66 provides "Dust-Tight" (level 6), while IP42 provides "> 1 mm — Small Wires" (level 4). IP66 is 2 levels higher.
Liquid protection
IP66
Level 6 — Powerful Water Jets (12.5 mm nozzle)
IP42
Level 2 — Dripping Water at 15° Tilt
IP66 handles 100 kPa (Powerful Water Jets (12.5 mm nozzle)), while IP42 handles 0.3 mm/min drip rate (Dripping Water at 15° Tilt). 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.