Insulation resistance test requirements: After the electrical lines are installed, before energization, an insulation resistance test should be conducted for all electrical lines (including exposed and concealed lines, as well as cables), and those that do not meet the insulation requirements must not be energized.
Purpose of insulation resistance test: Through the insulation resistance test, inspect and grasp the construction quality of the line laying and electrical installation, and avoid electrical safety accidents such as leakage and short circuit.
Insulation resistance testing method:
1. For the exposed wiring, concealed wiring and low-voltage cables during the laying of electrical lines, insulation tests should be conducted.
2. Conduct the test using a 500V digital insulation resistance tester. The testing equipment must have a valid certificate of measurement (including model, serial number, and validity period).
3. Lines and equipment below 48V should be tested in the same manner as single-phase 220V lines.
4. The number of tests conducted by the insulation resistance tester must match the number of circuits as specified in the design drawing. That is, tests should be carried out for each electrical circuit.
5. During the line test, the insulation resistance between the wires and the resistance of the wires to the ground should be greater than 0.5 MQ.
6. The insulation test value of the motor should be ≥ 1 MQ.
7. The insulation test values for large electrical equipment, switches, power supplies, and lighting distribution boxes should be greater than 0.5 MΩ.
8. Carefully fill out the insulation resistance test form and have it inspected and signed off by the relevant departments or the property owner.
According to the relevant regulations, it is:
The insulation resistance value of the low-voltage lighting circuit should be no less than 0.5 megohms.
The insulation resistance value of the motor power circuit should be no less than 1 megohm.
The insulation resistance value of the low-voltage power cable line should be no less than 10 megohms.
The insulation resistance value of the high-voltage power cable line should be no less than 400 megohms.
Post time: Jul-24-2026