UL 1561-2023
Standard for Dry-Type General Purpose and Power Transformers

Standard No.

UL 1561-2023

Release Date

2023

Published By

Underwriters Laboratories (UL)

Lastest

UL 1561-2023

Scope

1.1 These requirements cover: a) General purpose and power transformers of the air-cooled, dry, ventilated, and nonventilated types to be used in accordance with the National Electrical Code, ANSI/NFPA 70. Constructions include step up, step down, insulating, and autotransformer type transformers as well as air-cooled and dry-type reactors or b) General purpose and power transformers of the exposed core, air-cooled, dry, and compoundfilled types rated more than 10 kVA to be used in accordance with the National Electrical Code, ANSI/NFPA 70. Constructions include step up, step down, insulating, and autotransformer type transformers as well as air-cooled, dry, and compound-filled type reactors. 1.2 These requirements do not cover ballasts for high intensity discharge (HID) lamps (metal halide, mercury vapor, and sodium types) or fluorescent lamps, exposed core transformers, compound-filled transformers, liquid-filled transformers, voltage regulators, general use or special types of transformers covered in requirements for other electrical equipment, autotransformers forming part of industrial control equipment, motor-starting autotransformers, variable voltage autotransformers, transformers having a nominal primary or secondary rating of more than 600 volts, or overvoltage taps rated greater than 660 volts. 1.3 These requirements do not cover transformers provided with waveshaping or rectifying circuitry. Waveshaping or rectifying circuits may include components such as diodes and transistors. Components such as capacitors, transient voltage surge suppressors, and surge arresters are not considered to be waveshaping or rectifying devices.

UL 1561-2023 history

• 2023 UL 1561-2023 Standard for Dry-Type General Purpose and Power Transformers
• 2019 UL 1561 BULLETIN-2019 UL Standard for Safety Dry-Type General Purpose and Power Transformers (COMMENTS DUE: April 22@ 2019)
• 1970 UL 1561-2019 UL Standard for Safety Dry-Type General Purpose and Power Transformers
• 2018 UL 1561 BULLETIN-2018 UL Standard for Safety Dry-Type General Purpose and Power Transformers (COMMENTS DUE: October 29@ 2018)
• 2015 UL 1561 BULLETIN-2015 UL Standard for Safety Dry-Type General Purpose and Power Transformers (COMMENTS DUE: February 9@ 2015)
• 2014 UL 1561 BULLETIN-2014 UL Standard for Safety Dry-Type General Purpose and Power Transformers
• 2012 UL 1561 BULLETIN-2012 UL Standard for Safety Dry-Type General Purpose and Power Transformers (COMMENTS DUE: May 07@ 2012)
• 2011 UL 1561-2011 UL Standard for Safety Dry-Type General Purpose and Power Transformers (Fourth Edition; Reprint with Revisions Through and Including June 16, 2015)
• 2010 UL 1561 BULLETIN-2010 UL Standard for Safety Dry-Type General Purpose and Power Transformers (COMMENTS DUE: JANUARY 31@ 2011)
• 2005 UL 1561 BULLETINS-2005 CSDS 07/22/2005 (2p)
• 2005 UL 1561 BULLETIN-2005 UL Standard for Safety Dry-Type General Purpose and Power Transformers
• 2004 UL 1561 BULLETINS-2004 UL Standard for Safety Dry-Type General Purpose and Power Transformers (09/17/2004 (8p); 01/19/2004 (40p))
• 2003 UL 1561 BULLETINS-2003 09/17/2003 (34p)
• 2003 UL 1561 BULLETIN-2003 UL Standard for Safety Dry-Type General Purpose and Power Transformers
• 1999 UL 1561-1999 UL Standard for Safety Dry-Type General Purpose and Power Transformers Third Edition; Reprint With Revisions Through and Including 9/15/2005
• 1994 UL 1561-1994 Dry-type general purpose power transformers