UL 1561:2019 PDF Download

The UL 1561:2019 standard provides requirements for different types of dry transformers used in accordance with the National Electrical Code (NEC), ANSI/NFPA 70. The standard covers both air-cooled, dry, ventilated, and nonventilated transformers, as well as exposed core, air-cooled, dry, and compound-filled transformers with a rating of more than 10 kVA.

The standard specifies various types of transformers, including step up, step down, insulating, and autotransformer types, as well as air-cooled, dry, and compound-filled reactors. However, it excludes ballasts for high-intensity discharge (HID) lamps or fluorescent lamps, exposed core transformers, compound-filled transformers, liquid-filled transformers, voltage regulators, and transformers with a nominal rating of more than 600 volts or overvoltage taps rated higher than 660 volts.

Additionally, the UL 1561:2019 standard does not cover transformers equipped with waveshaping or rectifying circuitry. Components such as diodes and transistors in such circuitry are not considered waveshaping or rectifying devices, while items like capacitors, transient voltage surge suppressors, and surge arresters are not included in this standard.