UL Standard for Safety Transformers@ Distribution@ Dry-Type - over 600 Volts (Third Edition; Reprint with Revisions Through and Including November 07@ 2002)
These requirements cover single-phase or three-phase@ dry-type@ distribution transformers@ including solid cast and resin encapsulated transformers. The transformers are provided with either ventilated or non-ventilated enclosures and are rated for a primary or secondary voltage from 601 to 35000 V.These transformers are intended for installation in accordance with the National Electrical Code@ ANSI/NFPA 70.These requirements do not cover the following transformers:a) Instrument transformersb) Step-voltage and induction voltage regulatorsc) Current regulatorsd) Arc furnace transformerse) Rectifier transformersf) Specialty transformers (such as rectifier@ ignition@ gas tube sign transformers@ and the like)g) Mining transformersh) Motor-starting reactors and transformersThese requirements do not cover transformers under the exclusive control of electrical utilities utilized for communication@ metering@ generation@ control@ transformation@ transmission@ and distribution of electric energy regardless of whether such transformers are located indoors@ in buildings and rooms used exclusively by utilities for such purposes; or outdoors on property owned@ leased@ established rights on private property or on public rights of way (highways@ streets@ roads@ and the like).