Power cables with extruded insulation and their accessories for rated voltages from 1 kv um 1 2 kv up to 30 kv um 36 kv part 1.
Insulation resistance test standard for cable.
It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs.
Insulation resistance testing is a non destructive test procedure.
Deviations from the baseline information permit evaluation of the insulation.
Table 100 22 minimum radii for power cable.
The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms.
Also acceptable values of insulation resistance depend upon the equipment you re testing.
Principle of insulation testing and influencing factors insulation resistance measurement is based on ohm s law.
Historically many field electricians use the somewhat arbitrary standard of 1 megohm per kv.
The insulation resistance test consists in measuring the insulation resistance of a.
If insulation resistance of the cable is found between 1000 and 100 kω km at buried temperature the subject cable should be replaced urgently within a year.
Minimum acceptable insulation resistance for 600 v cable from 100 to 1000 feet.
Regular testing of the insulation on an installation or machine is therefore a useful way of monitoring this type of deterioration so you can act before total failure occurs.
Insulation resistance test data may be used to establish a trending pattern.
Insulation resistance testing purpose.
If during periodical testing insulation resistance of cable is found between 5 and 1 mω km at buried temperature the subject cable should be programmed for replacement.
The insulation resistance test is the second test required by the electrical safety testing standards.
Cables for rated voltages of 1 kv um 1 2 kv and 3 kv um 3 6 kv reference number.
For cables rated 600 v the minimum acceptable insulation resistance values for cable lengths from 100 to 1000 feet would be as shown in the following table from ieee 525.
After dc overpotential test is completed the insulation resistance test is done again to assure that the cable has not been damaged by the hi pot.
The test measures the insu lation resistance between the phases and or between phase and ground.
Insulation resistance decreases in temperature or moisture.
Test results are dependent on the temperature of the insulating material and the humidity of the surrounding environment at the time of the test.
With a little record keeping and common sense however you can get a good picture of the insulation condition from values that are only relative.
