scope:

This standard is intended for use as a basis for determining the energy-efficiency performance of the equipment covered and to assist in the proper selection of such equipment.

This standard covers single-phase and three-phase dry-type and liquid-immersed distribution transformers as defined in the following table:

Products excluded from this standard include:

a. Liquid-immersed transformers below 10 kVA

b. Dry-type transformers below 15 kVA

c. Drive transformers, both AC and DC

d. All rectifier transformers and transformers designed for high harmonics

e. Autotransformers

f. Non-distribution transformers, such as UPS transformers

g. Special impedance, regulation, and harmonic transformers

h. Regulating transformers

i. Sealed and non-ventilated transformers

j. Retrofit transformers

k. Machine tool transformers

l. Welding transformers

m. Transformers with tap ranges greater than 15%

n. Transformers with frequency other than 60 Hz

o. Grounding transformers

p. Testing transformers