NEMA 4X Rated LED Lighting

What NEMA 4X Means

NEMA 4X combines the water and dust protection of NEMA 4 with added corrosion resistance, making it a common requirement anywhere washdown procedures or corrosive substances are present. The rating is defined by the National Electrical Manufacturers Association (NEMA) and is widely used in North American specifications, particularly in food and beverage, chemical, and marine-adjacent applications.

Unlike the IP rating system (which is international and numeric), NEMA ratings are specific to North American standards and combine several protective criteria — ingress, corrosion resistance, and in some cases additional criteria like ice formation resistance — into a single classification.

NEMA 4X vs. IP66/IP67

NEMA and IP ratings address overlapping but not identical criteria:

• NEMA 4X includes corrosion resistance as part of its rating criteria, in addition to dust and water ingress protection.
• IP66/IP67 address dust and water ingress specifically, without a built-in corrosion resistance requirement.

Many industrial fixtures carry both a NEMA and an IP rating, since specifications in North America commonly reference NEMA while international projects may reference IP — confirm which standard your project requires.

Where NEMA 4X Is Needed

• Food and beverage processing facilities — frequent washdown and corrosion-prone cleaning agents
• Chemical and petrochemical plants — corrosive atmosphere and wash-down requirements
• Coastal and marine-adjacent industrial sites — salt-air corrosion combined with moisture exposure

Salt Spray Testing (720-Hour Standard)

Salt spray testing (per ASTM B117) exposes a fixture to a continuous salt fog environment for a set duration to evaluate corrosion resistance over time. A 720-hour rating — 30 days of continuous exposure — is a common benchmark for Marine-Grade Lighting and NEMA 4X-rated fixtures, and is worth requesting as supporting documentation alongside the NEMA rating itself, since NEMA 4X confirms enclosure design but salt spray hours confirm actual material and coating performance under sustained corrosive exposure.

Choosing the Right Fixture

Confirm whether your project specification calls for NEMA or IP ratings (or both), and evaluate corrosion exposure specifically — NEMA 4X's corrosion resistance criteria make it a stronger fit than IP66/IP67 alone for facilities with washdown chemicals, salt air, or other corrosive conditions.