Insulation resistance tester generally refers to megohmmeter, which is a measuring instrument commonly used by electricians. It is mainly used to check the insulation resistance of electrical equipment, household appliances or electrical lines to the ground and between phases, so as to ensure that these equipment, appliances and lines work in a normal state and avoid accidents such as electric shock casualties and equipment damage.

Meaning of terminal symbol:

When measuring the insulation resistance, the line "L" is connected to the conductive part of the measured object insulated from the earth, the ground "E" is connected to the shell or grounding part of the measured object, and the shield "G" is connected to the protective shielding part of the measured object or other parts that do not participate in the measurement.

So as to eliminate the error caused by instrument leakage. When measuring the insulation resistance between components of electrical products, "L" and "E" can be terminated on any group of wires. For example, when measuring the interphase insulation of the generator, three groups can be exchanged in turn, and the empty group is safely grounded.