STEP 1 Set your Multimeter to AC Volts and the appropriate voltage scale range you expect to read. STEP 2 Checking 240V Single Phase Voltage • Place your multimeter leads on L1 and L2. Your meter should read the proper line voltage. • Place your multimeter leads on L1 to ground and then L2 to ground. Your meter should read approximately ½ of your line voltage. Example 240V line voltage will read 120V each line to ground.