In the actual work, the use of megohmmeter to measure the insulation resistance is often complicated in the workplace. There are many high and low voltage equipments with live operation around and dangerous sources of insufficient understanding of the performance characteristics of the equipment under test. If not taken seriously, Measuring the insulation resistance will cause serious harm to the safety of people and equipment, and care must be taken.

Megohmmeter use safety precautions:

1) At least two people must participate in the measurement of the insulation resistance using a megger in the vicinity of the live equipment. The instrument, wiring, and human body should maintain a sufficient safety distance for the live equipment, and the test leads should not be pulled vigorously and the working range should be expanded;

2) All power supplies connected to the device under test must be cut off before measurement, and the device under test should be short-circuited to ground. Never use a megohmmeter to measure the insulation resistance of a charged device or a device that has not been discharged after a power failure, so that not only the correct measurement results, but also great danger or damage to the person and equipment;

3) For devices that are likely to induce high voltages, never use a megohmmeter to measure them until the possibility is eliminated.

4) Never touch the megohmmeter terminal or the device under test until the megger has not stopped rotating or the device under test has not been discharged. Especially when testing a device with a large capacitance, it is necessary to short-circuit the measured object to the ground before stopping the rotation of the megohmmeter and performing the disconnection.