When the megohmmeter is working, it generates high voltage by itself, and the measurement object is electrical equipment, so it must be used correctly, otherwise it will cause personal or equipment accidents. Before use, you must first make the following preparations:

(1) Before measurement, the power supply of the equipment under test must be cut off and short-circuited to ground. Never allow the equipment to be charged for measurement to ensure the safety of people and equipment.

(2) For equipment that may induce high voltage, this possibility must be eliminated before measurement.

(3) The surface of the measured object should be clean to reduce the contact resistance to ensure the accuracy of the measurement result.　

(4) Before measurement, check whether the megohmmeter is in normal working condition, mainly check its "0" and "∞" points. That is, shake the handle to make the motor reach the rated speed. The megohmmeter should point to the "0" position when it is short-circuited, and it should point to the "∞" position when it is open.

(5) When using the megohmmeter, it should be placed in a stable and firm place, and far away from large external current conductors and external magnetic fields.

The measurement can be performed after the above preparations are done. When measuring, pay attention to the correct wiring of the megohmmeter, otherwise it will cause unnecessary errors or even errors.