The cable 380V requirement is not less than 0.5 megohm.
The insulation resistance value of newly installed and overhauled low-voltage lines and equipment should not be less than 0.5 megohms.
The insulation resistance value of operating low-voltage lines and equipment should not be less than 1 kiloohm per voltage. For example, at 220V, the insulation resistance value should not be less than 0.22 megohms, and at 380V it should not be less than 0.38 megohms.
The insulation resistance value of circuits and equipment in humid environments should not be less than 500 ohms per volt.
Insulated wires for portable electrical equipment or hand-held power tools should not be less than 2 megohms.
The insulation resistance value of the control circuit should not be less than 1 megohm. In humid environment, it can be reduced to 0.5 megohms.
The insulation resistance value of each suspension insulator of overhead lines should not be lower than 300 megohms.
The insulation resistance value of high-voltage lines and equipment is generally not less than 1000 megohms.
The insulation resistance value of 6 to 10 kV cable lines is not less than 400 to 1000 megohms.
The insulation resistance value of the power transformer before it is put into operation should not be lower than 70% of the factory value, and can be appropriately reduced during operation.
