Glossary
Materials and construction
NEMA enclosure rating
Also known as NEMA 4, NEMA 4X, NEMA 12, NEMA rating.
NEMA enclosure ratings are the US National Electrical Manufacturers Association standards for electrical-enclosure protection, paralleling the IEC IP code used internationally. Common ratings encountered on sonic-horn accessories:
| NEMA rating | Description | IP equivalent |
|---|---|---|
| NEMA 4 | Watertight; indoor / outdoor | IP66 |
| NEMA 4X | Watertight + corrosion-resistant | IP66 + |
| NEMA 7 | Class I Div 1 hazardous-area | (no direct IP equivalent) |
| NEMA 9 | Class II Div 1 hazardous-area (dust) | (no direct IP equivalent) |
| NEMA 12 | Industrial indoor, dust-tight | IP55 |
Cross-referencing
US-market sonic-horn installations typically specify NEMA ratings; European-market installations use IP ratings. Vendors serving both markets cite the equivalent rating from the other standard for clarity.