General Equipment Safety Rules Always make certain the multimeter is connected in series with the circuit when making current measurements. Always make sure the meter is switched off when not in use to prolong battery life. Never connect more than 500V above ground. Never connect the multimeter to a voltage source with the function switch set in the: - Ohms setting or DIODE position. Never operate the multimeter unless the battery cover in place and fully closed. Never attempt battery and /or fuse replacement until the test leads have been disconnected and the power has been turned off. Never connect the meter in parallel to measure current. This could cause the overload protection to blow, damage the meter or the circuit under test.