Independent Electrical Contractors (IEC) Year 2 Part 3 Practice Test 2025 - Free Electrical Contractor Exam Questions and Study Guide

To determine the voltage that will be applied to the control panel requiring 208 volts with an input voltage of 240 volts when using a 120/240V-12/24V transformer, we consider the transformer ratio and how it steps down voltage.

The transformer is designed to convert 240 volts to a lower secondary voltage. The specification of 120/240V indicates that the primary side can handle up to 240 volts, which is then transformed to a lower voltage on the secondary side.

In this case, with a 12/24V designation, it’s essential to understand how the ratios work. If the transformer reduces the primary voltage of 240 volts to achieve a specific secondary voltage, you can calculate the expected output. The transformer effectively steps down the voltage in a proportional manner based on the turns ratio.

Given that the control panel is designed for 208 volts, a common target with transformers is to achieve voltages close to the requirement. The output voltage provided by a 120/240 volt transformer setup, when supplying a 240 volt input, will be close to the specified voltage when calculated using the relationship of the turns ratio and the load on the transformer.

By understanding the step-down function of the transformer and how it mod