If circuit voltage is unknown, what is one method to find it?

The method of checking the transformer nameplate and its connections is a valid approach to determine the circuit voltage when it is unknown. The nameplate on a transformer typically provides key information, including the rated primary and secondary voltages. By examining the connections and noting the transformer’s specifications, you can derive the expected circuit voltage based on how the transformer is configured in the electrical system. This approach is particularly useful because it ensures that voltage is assessed in context with the equipment being used and can help confirm if it aligns with the expected operational parameters.

Using a multimeter, while an effective tool for measuring voltage directly, may not always be possible if the circuit is de-energized or if there are safety concerns. Similarly, relying on a low voltage test instrument could limit the range of voltages that can be assessed and may not provide the necessary information if the voltage is above that threshold. Asking a supervisor could yield answers, but it might not be the most efficient or reliable method compared to the direct examination of transformer specifications.