Cable hi-pot withstanding time, why 15 minutes?

[DanielTronco]

IEEE NETA ANSI and other standards exist for a reason. The 15 minutes has a purpose. Just test according to the spec and record your results. If your just looking to do whatever you feel like then what's the point of standards and procedures.

[ARNOLD ZIFFEL]

tie all three cables together, do a gang test, and roll out early.

There is absolutely no reason not to hipot test all 3 phases of an MV shielded cable at one time. Neta specifies individual insulation resistance test but never states that phases must be hipotted seperately. As long as the shields are cont. tested and grounded at both ends for testing, any cable or termination fault will show itself in a gang test. And then you can test individually if needed.

[SecondGen]

NETA ATS-2013 references ICEA, IEC, IEEE and "other power cable consensus standards" as acceptable means of testing and says "the selection shall be made after an evaluation of the available test methods and a review of the installed cable system."

NETA MTS-2011 says "it is only after careful analysis of all circuit parameters between the testing entity and the cable owner that a preferred testing method be selected."


Nowhere in either NETA standard could I find where it specifically says to test each cable individually. Seems to me like it is up to the commissioning agency or cable owner to decide.

IEEE NETA ANSI and other standards exist for a reason. The 15 minutes has a purpose. Just test according to the spec and record your results. If your just looking to do whatever you feel like then what's the point of standards and procedures.

[robertellis87]

You can definitely tell the difference in the caliber of technicians with posts like that. Why does it matter that tech "A" has a level 4 NETA cert and and tech "B" has a level 2 NETA cert if the technicians take shortcuts like that? These certifications are a joke, especially when your pay/raises are dependent on them. What good does it do to obtain the certification if you're going to offer sub-par testing to your customer? If you hi-pot the three together and get 120 micro-amps of leakage current, but independently you would have seen 2 micro, 3 micro, and 115 micro respectively, you don't see that as a reason to investigate a little? Don't give me that "it didn't trip the test set so it passes" crap either. We all know you can spot a deteriorated cable/stress cone.

[Biscuit]

Just goes to show that certifications like these and pay scales based on them are bogus. I've seen guys pass the level III who are way less skilled than others who take the same test 2-3 times before passing. Some people just aren't good test takers. Everything should be based on job performance.

[Jay Knight]

yup, and other people cheat

Some people just aren't good test takers.

[jcisneros]

Megger before hipot. This can also help identify any damage to the cables prior to hipotting.

[Will Ward]

I just was taught that way a long time ago but never really got a good reason why it is done... The results are usually worse by maybe 10%

[Will Ward]

The pre withstand test with the Megger is obvious and mandatory.... It was the post test that I question the necessity... In my area the utility will specify the gang test procedure often when they witness a cable test.... I've had that same conversation with them about not being able to identify the distribution of the leakage current.... Some listen, some don't, some listen, agree and tell me do it there way anyway... Our procedure has always been individually unless directed by the AHJ

[Will Ward]

You mean I can't just wave that NETA card over a broken breaker and it won't fix itself????
Some of the brightest guys I know working with the equipment we do have a hard time with NETA exams...