Wire Cable Insulation Resistance Test Values

This type of test is a go no go type of test and is to determine if the insulation has been damaged during installation.

Wire cable insulation resistance test values.

B kv is the rated machine terminal to terminal voltage. For a good cable you will see results similar to those on the following page. Insulation resistance testing of low voltage cables in the field. Curve b shows same values corrected to 20 c see page 22 giving a definite downward.

Figure 4 typical record of insulation resistance of a mill motor. You have a single conductor 500 kcmil 15kv cable. Installation insulation resistance tests are only to be performed on new wire and cable. 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.

You perform this insulation resistance test on the cable and record the data on a copy of the attached form. Curve a shows test values as measured. A rated line to line voltage for three phase ac machines line to ground voltage for single phase machines and rated direct voltage for dc machines or field windings. Since 80 of electrical maintenance and testing.

Also acceptable values of insulation resistance depend upon the equipment you re testing. 3 shows a typical scale which reads increasing resistance values from left up to infinity or a resistance too high to be measured. 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. Even when not required by the end customer many wire and cable manufacturers use the insulation resistance test to track their insulation manufacturing processes and.

Ansi neta mts 2015 table 100 11 insulation resistance test values rotating machinery for one minute at 40 c. The results obtained from ir test are not intended to be useful in finding localized defects in the insulation as in a true hipot test but rather give information on the quality of the bulk material used as the insulation. The resistance values will increase over time due to capacitive and insulation charging. Historically many field electricians use the somewhat arbitrary standard of 1 megohm per kv.

The results obtained from ir test are not intended to be useful in finding localized defects in the insulation as in a true hipot test but rather give information on the quality of the bulk material used as the insulation. Wire and cable manufacturers use the insulation resistance test to track their insulation manufacturing processes and. For cables rated 600 v the minimum acceptable insulation resistance values for cable lengths from 100 to 1000 feet would.