Zatarra64
All around wannabe knowitall
- Location
- Phoenix, Az
- Occupation
- Electrical QA/QC
I have a procedural question on Megger testing cable at a new site.
I've gone over the 1587 FC manual, every YouTube video, and every "guide" I can find, but none of them quite match up, or are based on older test equipment and standards.
I'm fairly confident that I do know what I'm doing, but I'm having difficulty verifying it.
I have to megger test multiple copies of 4 cables. (Three phase, and one ground Green, Brown, Yellow, Orange). None of the cables are landed at either end.
I'm looking for steps to verify testing is being done correctly, because I am sure it currently is not.
Current steps as witnessed:
Cables are ran between the two locations.
Tape is applied to the end of each cable at location B.
End of insulation is stripped from all 4 cables at location A.
Worker attaches the black alligator clamp to the Green wire and taps each of the other cables sometimes hitting the "test" button while the lead is touching, and sometimes not. Worker moves the alligator clamp and lead to test between A-B, A-C, B-C, and A/B/C to the (NOT CONNECTED) Ground wire.
Worker shows >2.2G-ohm for each measurement.
At no point were any of these cables landed on either end, and at no point were any of them tested vs a know good "ground" source.
My old memory of using a megger says it takes longer than tapping each wire, and that I need to test vs a "known good" ground source.
I believe that the current method is just testing open air.... Or the random chance that there is damaged insulation near enough to two points for it to register.
I have no idea where in NETA/NEC or anywhere else it describes HOW to do a correct test, or if there are any updates to the test based on updated technology in the FLUKE 1587 FC.
Any help or direction would be greatly appreciated.
-Rob
I've gone over the 1587 FC manual, every YouTube video, and every "guide" I can find, but none of them quite match up, or are based on older test equipment and standards.
I'm fairly confident that I do know what I'm doing, but I'm having difficulty verifying it.
I have to megger test multiple copies of 4 cables. (Three phase, and one ground Green, Brown, Yellow, Orange). None of the cables are landed at either end.
I'm looking for steps to verify testing is being done correctly, because I am sure it currently is not.
Current steps as witnessed:
Cables are ran between the two locations.
Tape is applied to the end of each cable at location B.
End of insulation is stripped from all 4 cables at location A.
Worker attaches the black alligator clamp to the Green wire and taps each of the other cables sometimes hitting the "test" button while the lead is touching, and sometimes not. Worker moves the alligator clamp and lead to test between A-B, A-C, B-C, and A/B/C to the (NOT CONNECTED) Ground wire.
Worker shows >2.2G-ohm for each measurement.
At no point were any of these cables landed on either end, and at no point were any of them tested vs a know good "ground" source.
My old memory of using a megger says it takes longer than tapping each wire, and that I need to test vs a "known good" ground source.
I believe that the current method is just testing open air.... Or the random chance that there is damaged insulation near enough to two points for it to register.
I have no idea where in NETA/NEC or anywhere else it describes HOW to do a correct test, or if there are any updates to the test based on updated technology in the FLUKE 1587 FC.
Any help or direction would be greatly appreciated.
-Rob
