UL 506

Specialty Transformers

UL 506

1 Scope

1.1 These requirements cover ignition transformers for use with gas burners and oil burners and specialty step-up transformers used in applications such as insect electrocuting. Transformers incorporating overcurrent or over-temperature protective devices, transient voltage surge protectors, or power factor correction capacitors are also covered by these requirements. These transformers are intended to be used in accordance with the National Electrical Code, NFPA 70.

1.2 These requirements do not cover liquid-immersed transformers, variable voltage autotransformers, transformers having a nominal primary rating of more than 600 volts, transformers having overvoltage taps rated over 660 volts, cord and plug connected transformers, garden light transformers, voltage regulators, swimming pool and spa transformers, or other special types of transformers covered in requirements for other electrical devices or appliances.

1.3 These requirements do not cover:

a) Autotransformers used in industrial control equipment, which are evaluated in accordance with the Standard for Industrial Control Equipment, UL 508.

b) Class 2 or Class 3 transformers, which are evaluated in accordance with the Standard for Low Voltage Transformers – Part 1: General Requirements, UL 5085-1, and the Standard for Low Voltage Transformers – Part 3: Class 2 and Class 3 Transformers, UL 5085-3.

c) Toy transformers, which are evaluated in accordance with the Standard for Toy Transformers, UL 697.

d) Transformers for use with radio- and television-type appliances, which are evaluated in accordance with the Standard for Transformers and Motor Transformers for Use in Audio-, Radio-, and Television-Type Appliances, UL 1411.

e) Transformers for use with high intensity discharge lamps, which are evaluated in accordance with the Standard for High-Intensity-Discharge Lamp Ballasts, UL 1029.

f) Transformers for use with fluorescent lamps, which are evaluated in accordance with the Standard for Fluorescent-Lamp Ballasts, UL 935.

g) Ventilated transformers for general use or non-ventilated transformers for general use (other than compound filled or exposed core types), which are evaluated in accordance with the Standard for Dry-Type General Purpose and Power Transformers, UL 1561.

h) Dry-type distribution transformers rated over 600 volts, which are evaluated in accordance with the Standard for Transformers, Distribution, Dry-Type – Over 600 Volts, UL 1562.

i) Transformers incorporating rectifying or waveshaping circuitry evaluated in accordance with the Standard for Power Units Other Than Class 2, UL 1012.

j) Transformers of the direct plug-in type evaluated in accordance with the Standard for Class 2 Power Units, UL 1310.

k) Transformers for use with electric discharge and neon tubing, which are evaluated in accordance with the Standard for Neon Transformers and Power Supplies, UL 2161.

l) General purpose and industrial control transformers evaluated in accordance with the Standard for Low Voltage Transformers – Part 1: General Requirements, UL 5085-1, and the Standard for Low Voltage Transformers – Part 2: General Purpose Transformers, UL 5085-2.