What is considered Low Voltage for distribution transformers?

The term “Low Voltage” for electrical distribution transformers can refer to different voltages. Generally transformers with primary and secondary voltages at or below 600 volts are considered “Low Voltage”.

• 690 Volts is sometimes considered low voltage. It is sometimes referred to as a 600/690 volt system.
• The National Electric Code considers voltages <1000 volts to be low voltage.
• Some regulatory agencies consider 1.2 kV and below to be low voltage.

As a result there is some market confusion for voltages between 600 and 1200 volts with some regulations having a definition gap for some of these voltages.