Insulation resistance testing equipment.

[hoatiett]

My first time posting here, but I am a nicet1 technician. My company does tons of acceptance testing for multiple projects and a good potion requires insulation testing. Question to everyone on this thread, is it okay to use a FLUKE 1587FC on small electrical equipment (1000v or less) or is it preferable to use a larger test kit such as the MEGGER S1-1568 5kV for small and large electrical equipment? The reason I ask it because we have an enginneer/technican insist the entire team test with S1-1568 because it gives a better and larger resistance (7.5T) and would have customer satisfy because its a high resistance reading compare to FLUKE 1587 where its max reading is at 2.2G. All job specs we had contracts with doesnt have a preferences on what test equipment we used, so long as we follow NETA ATS guideline. I would mainly use the fluke 1587FC on small sub-panels, low voltage breakers, and cables. However, I would use the S1-1568 on medium voltage switchgear and vacuum circuit breakers.

TLDR; Is it okay to use the fluke 1587FC on smaller electrical equipment, so long as I am following the NETA ATS guideline or is it preferably using the S1-1568 for smaller electrical equipment also?

[TestTech]

My first time posting here, but I am a nicet1 technician. My company does tons of acceptance testing for multiple projects and a good potion requires insulation testing. Question to everyone on this thread, is it okay to use a FLUKE 1587FC on small electrical equipment (1000v or less) or is it preferable to use a larger test kit such as the MEGGER S1-1568 5kV for small and large electrical equipment? The reason I ask it because we have an enginneer/technican insist the entire team test with S1-1568 because it gives a better and larger resistance (7.5T) and would have customer satisfy because its a high resistance reading compare to FLUKE 1587 where its max reading is at 2.2G. All job specs we had contracts with doesnt have a preferences on what test equipment we used, so long as we follow NETA ATS guideline. I would mainly use the fluke 1587FC on small sub-panels, low voltage breakers, and cables. However, I would use the S1-1568 on medium voltage switchgear and vacuum circuit breakers.

TLDR; Is it okay to use the fluke 1587FC on smaller electrical equipment, so long as I am following the NETA ATS guideline or is it preferably using the S1-1568 for smaller electrical equipment also?

We have looked at it from a practical and economic angle:

Using LV breakers as an example, 600V equipment minimum Insulation Resistance is 100M per NETA. Typically the readings are much much higher of course. We use 1000V hand held meters that measure up to 4000M. If a LV breaker megs at 4000M we feel comfortable calling it good and enter >4000M on the test forms. Questionable readings would warrant using different equipment if necessary of course.

These handheld meters are true RMS DMM's with backlit screens, great battery life, incredibly rugged, read IR to 4000M and cost $160.00. A 5kV S1-1568 costs $5000.00. A set of test leads for a S1-1568 can cost 3X the cost of these meters.

A typical LV breaker project involves moving, racking, servicing large draw out 800A to 4000A power breakers, primary injection testing, Ductor etc. This is not the same as testing a 200A molded case breaker in a panelboard. The test equipment gets harsh duty. We would rather not trash a $5000 S1-1568 (and find out its broken on the next days job which involves a 20MVA Substation transformer where the Insulation Resistance readings actually do matter. The techs find it easier to use as you can perform other functions as well.

Most shops or techs will have their day to day equipment and "the good one" and know when to use each.

I guess I dont see the value in knowing the insulation resistance value of a LV circuit breaker was >7.5T if a value of >4000M is completely acceptable. We own many S1-1568 or similar 5kV Test Sets. We can and have used them on LV breaker projects but have chosen not to.

I would like to hear others views on this.

[hoatiett]

I guess I dont see the value in knowing the insulation resistance value of a LV circuit breaker was >7.5T if a value of >4000M is completely acceptable. We own many S1-1568 or similar 5kV Test Sets. We can and have used them on LV breaker projects but have chosen not to.

I would like to hear others views on this.

I really appreciate your insight on this because the idea has been driving me crazy! I plan on posting more of my curiosity in the future. Thanks!

[Kalbi_Rob]

My first time posting here, but I am a nicet1 technician. My company does tons of acceptance testing for multiple projects and a good potion requires insulation testing. Question to everyone on this thread, is it okay to use a FLUKE 1587FC on small electrical equipment (1000v or less) or is it preferable to use a larger test kit such as the MEGGER S1-1568 5kV for small and large electrical equipment? The reason I ask it because we have an enginneer/technican insist the entire team test with S1-1568 because it gives a better and larger resistance (7.5T) and would have customer satisfy because its a high resistance reading compare to FLUKE 1587 where its max reading is at 2.2G. All job specs we had contracts with doesnt have a preferences on what test equipment we used, so long as we follow NETA ATS guideline. I would mainly use the fluke 1587FC on small sub-panels, low voltage breakers, and cables. However, I would use the S1-1568 on medium voltage switchgear and vacuum circuit breakers.

TLDR; Is it okay to use the fluke 1587FC on smaller electrical equipment, so long as I am following the NETA ATS guideline or is it preferably using the S1-1568 for smaller electrical equipment also?

We have gotten into arguments with inspectors because one tech used an older megger insulation tester that maxed out at 999 ohms, and another that used a Fluke 1587 that maxed out at 2.2Gohms. His argument was that we couldn't verify the cables were good if we didn't see the actual value. We just started giving him readings of 999 ohms for all readings as max cause it is still 10x the minimum value required per NETA. Unfortunately, it really depends on the customer and what you can get away with.
If you are looking for a smaller unit to test that gives higher values, the newer Megger MIT 420 series have a maximum readings up to 200 GOhms at 1kV.

[Csloat217]

My company feels comfortable using hand meggers maxing out at 2.2k. We also usually stop at 1T for medium volt applications unless we are doing a test that calls for a certain minutes of testing. We haven't gotten any flack on it once we explain how much over passing that is. If I am troubleshooting and I see over 1T for a minute I feel comfortable calling it good whatever it might be.

We have looked at it from a practical and economic angle:

Using LV breakers as an example, 600V equipment minimum Insulation Resistance is 100M per NETA. Typically the readings are much much higher of course. We use 1000V hand held meters that measure up to 4000M. If a LV breaker megs at 4000M we feel comfortable calling it good and enter >4000M on the test forms. Questionable readings would warrant using different equipment if necessary of course.

These handheld meters are true RMS DMM's with backlit screens, great battery life, incredibly rugged, read IR to 4000M and cost $160.00. A 5kV S1-1568 costs $5000.00. A set of test leads for a S1-1568 can cost 3X the cost of these meters.

A typical LV breaker project involves moving, racking, servicing large draw out 800A to 4000A power breakers, primary injection testing, Ductor etc. This is not the same as testing a 200A molded case breaker in a panelboard. The test equipment gets harsh duty. We would rather not trash a $5000 S1-1568 (and find out its broken on the next days job which involves a 20MVA Substation transformer where the Insulation Resistance readings actually do matter. The techs find it easier to use as you can perform other functions as well.

Most shops or techs will have their day to day equipment and "the good one" and know when to use each.

I guess I dont see the value in knowing the insulation resistance value of a LV circuit breaker was >7.5T if a value of >4000M is completely acceptable. We own many S1-1568 or similar 5kV Test Sets. We can and have used them on LV breaker projects but have chosen not to.

I would like to hear others views on this.