What is the normal low-side rating of a potential transformer?

The low-side rating of a potential transformer is typically standardized to 120 volts. This value is commonly used because it aligns with the nominal voltage levels found in residential and commercial power distribution systems, allowing for efficient and safe voltage regulation and monitoring.

Potential transformers are designed to step down high voltages to lower levels that can be safely measured by metering equipment. For most applications, particularly in the United States, the 120-volt rating is a practical choice that ensures compatibility with typical electrical instrumentation. This rating facilitates the accurate measurement and control of electrical systems without subjecting the measuring devices to high voltages, which could damage equipment or pose safety risks.

In contrast, the other voltage levels, such as 5 volts, 240 volts, and 480 volts, do not represent the conventional low-side outputs for potential transformers in most applications. Therefore, 120 volts stands out as the standard level for operational efficiency and safety in monitoring systems.