Establishments primarily engaged in manufacturing power, distribution, instrument, and specialty transformers. Establishments primarily engaged in manufacturing radio frequency or voice frequency electronic transformers, coils, or chokes are classified in Industry 3677, and those manufacturing resistance welder transformers are classified in Industry 3548.
- Airport lighting transformers
- Auto-transformers for switchboards, except telephone switchboards
- Auto-transformers, electric (power transformers)
- Ballasts for lighting fixtures
- Control transformers
- Current limiting reactors, electrical
- Distribution transformers electric
- Doorbell transformers, electric
- Electric furnace transformers
- Feeder voltage regulators and boosters (electric transformers)
- Fluorescent ballasts (transformers)
- Generator voltage regulators electric induction and step type
- Ignition transformers
- Instrument transformers except portable
- Isolation transformers
- Lighting transformers, fluorescent
- Lighting transformers, street and airport
- Line voltage regulators
- Luminous tube transformers
- Machine tool transformers
- Ratio transformers
- Rectifier transformers
- Signaling transformers electric
- Specialty transformers
- Street lighting transformers
- Toy transformers
- Transformers, electric power
- Transformers, for electronic meters
- Transformers, reactor
- Tripping transformers
- Vibrators interrupter
- Voltage regulating transformers electric power
- Voltage regulators, transmission and distribution