The application, installation, operation, and maintenance of single- and polyphase dry-type general purpose, distribution, power, and autotransformers are covered. The following types are included: ventilated, indoor and outdoor, self- or forced-air cooled; nonventilated, indoor and outdoor, self- or forced-air cooled; and sealed, indoor and outdoor, self-cooled. Instrument transformers, step voltage and induction-voltage regulators, arc furnace transformers, rectifier transformers, and specialty transformers are not covered.