NEMA publishes reinstated dry type transformer standard.
Press Release Summary:
June 27, 2014 - NEMA has published NEMA ST 20-2014 Dry Type Transformers for General Applications, which applies to single-phase and polyphase dry-type transformers for supplying power, heating, and lighting circuits, and designed to be installed and used in accordance with National Electrical Code®. Standard also covers transformers with or without accessories having ratings of 1.2 kV class, 0.25–4,000 kVA. NEMA ST 20 specifically addresses sound levels for these types of transformers.
Original Press Release
NEMA Publishes Reinstated NEMA ST 20-2014 Dry Type Transformers for General Applications
Press release date: June 23, 2014
The reinstated and revised edition of NEMA ST 20 applies to single-phase and polyphase dry-type transformers (including autotransformers and non-current-limiting reactors) for supplying energy to power, heating, and lighting circuits, and designed to be installed and used in accordance with the National Electrical Code. It also covers transformers with or without accessories having ratings of 1.2 kV class, 0.25 kVA through 4000 kVA.
NEMA ST 20 is one of the few standards in the marketplace that specifically addresses sound levels for this particular type of transformer. The U.S. Army Corps of Engineers still references it in their criteria documents. Changes in the latest version include a single average sound level table, more alignment with IEEE (Institute of Electrical and Electronics Engineers), and a new appendix providing a brief introduction to U.S. efficiency regulations.
NEMA ST 20-2014 may be downloaded at no cost or purchased in hardcopy for $71on the NEMA website.
NEMA is the association of electrical equipment and medical imaging manufacturers, founded in 1926 and headquartered in Rosslyn, Virginia. Its 400-plus member companies manufacture a diverse set of products including power transmission and distribution equipment, lighting systems, factory automation and control systems, and medical diagnostic imaging systems. Total U.S. shipments for electroindustry products exceed $100 billion annually.
National Electrical Manufacturers Association
Visit our website at www.nema.org