Does UL Certify Air Compressors?


We’re struggling to find listed air compressors, does UL List (certify) air compressors?



Yes, UL certifies (Lists) air compressors under the product category Compressors, Vacuum Pumps and Pneumatic Paint Sprayers (QDGS), located on page 330 in the 2013 UL White Book. By accessing UL’s Online Certifications Directory at and entering QDGS at the category code search field, you can access the nearly 60 manufacturers that have certification under this category.

This category covers air compressors and vacuum pumps, including pneumatic-type paint sprayers rated 600 volts or less.

Products can be cord-connected or provided with means for permanent connection in the field. Permanently connected products are intended to be installed in accordance with ANSI/NFPA 70, National Electrical Code (NEC).

The basic standard used to investigate products in this category is ANSI/UL 1450, the Standard for Safety for Motor-Operated Air Compressors, Vacuum Pumps, and Painting Equipment.

If there is an uncertified compressor that is already installed in the field, UL can conduct a field evaluation on the compressor. For more information on field evaluations, or to schedule a field evaluation, call 877-ULHELPS (877-854-3577) or request this online at



Article 502 in the NEC permits electrical metallic tubing (EMT) as a wiring method in Class II, Division 2 hazardous classified locations provided the fittings are dust tight. The contractor wants to use certified (Listed) compression type EMT fittings suitable as rain tight. Are EMT fittings certified for use as “rain tight” also dust tight? Are there any certified dust tight EMT connectors?



EMT connectors that arecertified (Listed) as rain tight are certified for use in wet locations and not additionally evaluated as dust tight, there is no correlation between the two ratings. EMT fittings are certified under the product category Electrical Metallic Tubing Fittings (FKAV), located on page 151 in the 2013 UL White Book and also on UL’s Online Certifications Directory at and enter FKAV at the category code search field.

The Guide Information for FKAV states that fittings suitable for use where exposed to rain are so indicated on the device or carton. The terms “rain tight,” “wet location”or the equivalent on the carton indicates suitability for use where directly exposed to rain.

Consequently, there are no EMT fittings that are rated as dust tight, Type 4 or Type 4X. If EMT fittings were submitted for such a rating, UL would consider developing/expanding certification requirements, as necessary, for these type of fittings for use with EMT just as UL can currently evaluate EMT fittings for use with enclosures for other environments, in accordance with UL 514B, the Standard for Safety for Conduit, Tubing, and Cable Fittings.


I have encountered the installation of ceiling-mounted LCD or DLP projectors in suspended ceilings. From my perspective, NEC 400.8(5) would not allow a cord to be located above a suspended ceiling. Does UL certify (List) permanently mounted projectors, or any projectors in which the cord is located above the ceiling and permanently wired into a box?


No, UL does not certify (List) flexible cord connected projectors to be installed above a ceiling. LCD and DLP projectors are certified (Listed) under the product category Information Technology Equipment Including Electrical Business Equipment (NWGQ), located on page 277 in the 2013 UL White Book or on UL’s Online Certifications Directory at and enter NWGQ at the category code search field. Certified projectors would be certified to be installed in accordance with the NEC which prohibits flexible cords installed above or through a suspended ceiling.

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