W-T-631 Revision C, June 4, 1964
Includes all amendments and changes through Cancellation Notice 1, December 28, 2012
Additional Comments: CNCL NO S/S
This specification covers single-phase and three-phase 60 cycle, overhead-type, liquid-immersed, air-cooled distribution power transformers rated 500 kv.-a and smaller; high voltage, 67,000 volts and below; low voltage 15,000 volts and below.
Distribution transformers furnished under this specification shall be of the following types and classes, as specified (see 6.1).
Types: Type I--Mineral oil insulated. Type II--Nonflammable liquid insulated. Type III--Mineral oil insulated, wholly self-protected. Classes: Class 1--Single phase. Class 2--Three phase.
Transformers furnished under this specification shall be of standard commercial kv.-a and voltage ratings, as specified (see 6.1).