960 15 c for parts containing live components 850 15 c for cavity wall parts 650 15 c for all others.
Cable insulation resistance test standard iec.
Ieee400 1 2007 ieee guide for field testing of laminated dielectric shielded power cable systems.
Cables for rated voltages of 1 kv um 1 2 kv and 3 kv um 3 6 kv reference number iec 60502 1 2004 e international standard iec 60502 1 second edition 2004 04.
Whether it involves the connection cables the sectioning and protection equipment or the motors and generators the electrical conductors are insulated using materials with high electrical resistance in order to limit as much as possible the flow of current outside.
The equipment under test is brought into contact with the hot filament for 30 seconds.
Z 2 electrical insulation testing.
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.
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.
Insulation resistance decreases in temperature or moisture.
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.
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.
The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms.
Deviations from the baseline information permit evaluation of the insulation.
The resistance is determined by the glow wire test.
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.
Historically many field electricians use the somewhat arbitrary standard of 1 megohm per kv.
The temperature amounts to.
Insulation resistance testing guide.
The international electrical testing association neta specification maintenance testing specifications for electrical power distribution equipment and.
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 test data may be used to establish a trending pattern.
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.
This type of test is a form of preventative maintenance.