What must you do when checking for unknown voltage on a live circuit?

What must you do when checking for unknown voltage on a live circuit?

• A. Scale must be set at the highest scale
• B. Scale should be set to auto
• C. Use the lowest scale
• D. Use a separate meter

Answer: (A)

When checking for unknown voltage on a live circuit, you should set the meter to the highest voltage range first. This protects the meter from overrange and reduces the risk of damaging the input when the actual voltage is higher than you expect. Starting on the highest scale ensures you won’t exceed the meter’s limits, and if the reading sits safely within that range, you can then switch to a lower, more precise setting to get a clearer measurement. Using the lowest scale from the start could overload the meter and cause a blown fuse or damaged input, while auto scaling or using a separate meter isn’t necessary for this discipline.

When checking for unknown voltage on a live circuit, you should set the meter to the highest voltage range first. This protects the meter from overrange and reduces the risk of damaging the input when the actual voltage is higher than you expect. Starting on the highest scale ensures you won’t exceed the meter’s limits, and if the reading sits safely within that range, you can then switch to a lower, more precise setting to get a clearer measurement. Using the lowest scale from the start could overload the meter and cause a blown fuse or damaged input, while auto scaling or using a separate meter isn’t necessary for this discipline.