The international electrical testing association neta specification maintenance testing specifications for electrical power distribution equipment and.
Cable insulation resistance test standard iec.
Insulation resistance test data may be used to establish a trending pattern.
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.
Insulation resistance decreases in temperature or moisture.
Historically many field electricians use the somewhat arbitrary standard of 1 megohm per kv.
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.
Z 2 electrical insulation testing.
Table 100 22 minimum radii for power cable.
Deviations from the baseline information permit evaluation of the insulation.
Maintenance insulation resistance testing can be performed on a regular basis and the collected data used to indicate if the conductor insulation is deteriorating over time.
S iec 60840 edition 4 0 2011 11 iec standards power cables with extruded insulation and their accessories for rated voltages above 30 kv um 36 kv up to 150 kv um 170 kv test methods and requirements câbles d énergie à isolation extrudée et leurs accessoires pour des tensions.
The equipment under test is brought into contact with the hot filament for 30 seconds.
If the insulation resistance falls below an accepted user dictated value or falling rapidly over time then cable.
Test results are dependent on the temperature of the insulating material and the humidity of the surrounding environment at the time of the test.
Insulation resistance testing guide.
The temperature amounts to.
960 15 c for parts containing live components 850 15 c for cavity wall parts 650 15 c for all others.
Also acceptable values of insulation resistance depend upon the equipment you re testing.
This type of test is a form of preventative maintenance.
The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms.
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.
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.
11 ieee 400 2012 omnibus ieee guide for field testing and evaluation of the insulation of shielded power cable systems rated 5 kv and above.
The resistance is determined by the glow wire test.
