Will checking volts with an Ohm meter damage the meter?

Will checking volts with an Ohm meter damage the meter?

• A. Yes
• B. No
• C. Only if the meter is digital
• D. Only if you are measuring DC

Answer: (A)

Using the ohms function to test volts is risky because that mode relies on an internal current source to measure resistance. If you clip the leads to a live circuit and try to read the voltage, that test current is forced into the circuit and through the meter’s internal circuitry. The meter isn’t designed to handle external voltage in resistance mode, so it can blow a fuse or damage the input circuitry. This risk applies to both digital and analog meters and to AC or DC voltage. To measure voltage safely, switch the meter to the volts setting and measure across the live circuit (or disconnect power and measure resistance only when de-energized).

Using the ohms function to test volts is risky because that mode relies on an internal current source to measure resistance. If you clip the leads to a live circuit and try to read the voltage, that test current is forced into the circuit and through the meter’s internal circuitry. The meter isn’t designed to handle external voltage in resistance mode, so it can blow a fuse or damage the input circuitry. This risk applies to both digital and analog meters and to AC or DC voltage. To measure voltage safely, switch the meter to the volts setting and measure across the live circuit (or disconnect power and measure resistance only when de-energized).