Cable Insulation Resistance Test Standard

Insulation resistance testing purpose.

Cable insulation resistance test standard.

Principle of insulation testing and influencing factors insulation resistance measurement is based on ohm s law. It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs. 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. 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.

Hands down without a doubt one of the most universally searched topics on ec m s website from a historical perspective is insulation resistance testing as a result some of our most popular evergreen articles like understanding insulation resistance testing continue to top the charts when it comes to most popular content. Historically many field electricians use the somewhat arbitrary standard of 1 megohm per kv. 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. The document uses the standard numbering system of ansi and ieee.

The insulation resistance test is the second test required by the electrical safety testing standards. The measured resistance has to be higher than the indicated limit from the international standards. When overpotential testing cable its common practice to conduct the insulation resistance measurement first and then proceed with the dc overpotential test if acceptable readings are achieved. Cables for rated voltages of 1 kv um 1 2 kv and 3 kv um 3 6 kv reference number.

Since 1989 revised editions of the acceptance testing specifications have been published in 1991 1995 1999 2003 and 2007. Insulation resistance testing is a non destructive test procedure. The international electrical testing association neta specification maintenance testing specifications for electrical power distribution equipment and. 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.

Since 80 of electrical maintenance and testing. Insulation resistance decreases in temperature or moisture. The test measures the insu lation resistance between the phases and or between phase and ground. On february 19 2009 the american national standards institute approved the neta acceptance testing.

The insulation resistance test consists in measuring the insulation resistance of a device under test while phase and neutral are short circuited together. Ieee400 1 2007 ieee guide for field testing of laminated dielectric shielded power cable systems. 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.