Fluke 1587 Insulation Multimeter

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mikehughes8 said:
As for as the Pearl Reconditioning standards go if you go to the web site listed in my previous post. At the bottom of many of their tables it says "Reproduced from NETA MTS – 1997 Table 10.14"

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Table 10.14 is simply a temperature correction table for correcting your megger readings to 20 degrees C, has nothing to do with any testing procedures, and does not support your arguement at all. Tale 10.14 wasnt even derived by NETA, it is reproduced from the AVO publication "A stich in time".
 
I am actually going to grab the NETA standards today when I go by work to verify the specific testing requirements. I have no doubt that I have a lot to learn. That's exactly why I try to engage with others working in the industry. Unfortunately, many of my collegues accept our current practices while I tend to question them. For some reason we live and die by the megger and I know this is wrong. I am trying to encourage our Battalion to get the right testing equipment and develop a comprehensive maintenance and testing program more in-line with industry. To facilitate this I need to justify such expenditures with the requisit knowledge to support my position. This involves reading, research, and in some cases silly questions. So i apoligize in advance for the latter.
 
If you just wanted an insulation resistance tester, why didn't you go with the 1507 instead Bob:-? I guess you just wanted an all-in-one?????

You lost out on PI/DAR, maybe you don't need that.
 
76nemo said:
You lost out on PI/DAR, maybe you don't need that.
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I have done quite well in the trade for 25 years without even needing a mega. :cool: It has only been fairly recently that our contracts started requiring insulation testing.


It would be worthless to me to get a meter with 'PI/DAR' considering I don't have a clue what that means or what that would do.

We build schools, stores, offices, apartment buildings etc. What would I use "PI/DAR" for?
 
iwire said:
I have done quite well in the trade for 25 years without even needing a mega. :cool: It has only been fairly recently that our contracts started requiring insulation testing.


It would be worthless to me to get a meter with 'PI/DAR' considering I don't have a clue what that means or what that would do.

We build schools, stores, offices, apartment buildings etc. What would I use "PI/DAR" for?
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Don't you have service/maintenance contracts?
 
mikehughes8 said:
I am actually going to grab the NETA standards today when I go by work to verify the specific testing requirements. I have no doubt that I have a lot to learn. That's exactly why I try to engage with others working in the industry. Unfortunately, many of my collegues accept our current practices while I tend to question them. For some reason we live and die by the megger and I know this is wrong. I am trying to encourage our Battalion to get the right testing equipment and develop a comprehensive maintenance and testing program more in-line with industry. To facilitate this I need to justify such expenditures with the requisit knowledge to support my position. This involves reading, research, and in some cases silly questions. So i apoligize in advance for the latter.
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Thats fine, questions are always welcome, I know your pain, I was a Navy Nuke and we did all the same stuff, navy nukes and Army Prime Power guys make up the majority of the power system testing gene pool. We basically had the same procedures (DOD, DOE) as you and the same issues. Problem is a shop like mine has (Well) over $1M in electrical test equipment for circuit breakers, cables, and transformers, the gov isnt buying all that equipment for every submarine, battalion, etc (And if they did they would probally spend 5 times that much on the same stuff :)) so they have to make due with what they have.

The best answer is to farm out the high end testing when you can, we do on line PD testing, Tan Delta, Corona scans, all the expensive stuff, in fact if you are stationed where I think you are stationed we have a bid in for some PD testing next spring on base.
 
iwire said:
It would be worthless to me to get a meter with 'PI/DAR' considering I don't have a clue what that means or what that would do.

We build schools, stores, offices, apartment buildings etc. What would I use "PI/DAR" for?
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Inductive equipment mostly, motors and transformers.
 
ivsenroute said:
Holy crap. Over $200. for the NETA standards!
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thats nothing, look at the price of the IEEE "Color" book series, we have to buy these all the time after revisions.

No point in buying the NETA specs unless you have the equipment and ertified persons to follow them, after buying the equipment needed for most NETA testing procedures $200 is nothing.
 
Ok...not to dwell on the subject but NETA MTS-2007 has the following to say about insulation resistance test as it applies to low voltage cable.

7.3.2

600V Maximum

Test at 500V dc for 300V rated cable
Test at 1000V dc for 600V rated cable

It goes on to state the following for test values:

Insulation resistance values should be comparable to previously obtained results and similiar circuits but not less than 2 megohms.

Deviations in resistance between parallel conductors shall be investigated.

My previous assertion of 500megohms was obviously a mistake. That value is for XFMRs rated at 600V or less.
 
You dont need a megger that has a built in DAR/PI function to determine the DAR and PI ratio.

PI (polarization Index) is simply the ratio of your 10min reading to your 1 minute reading. (It's dependent on equipment class but a ratio of 2 to 1 usually indicates a good result) IEEE STD 43-2000

DAR (dielectric absorption ratio) is simply your 60 sec reading / 30 sec reading
Anything below a 1 is an indication of a problem
Above 1.4 Excellent


You can do the math yourself if the customer is requesting these values for some reason.
 
mikehughes8 said:
You dont need a megger that has a built in DAR/PI function to determine the DAR and PI ratio.

You can do the math yourself if the customer is requesting these values for some reason.
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Good point, everyone gets so lazy hese days. However, the customer will never ask for a PI or DAR, thats up to you as the expert to derive and analize the results.
 
zog said:
Good point, everyone gets so lazy hese days. However, the customer will never ask for a PI or DAR, thats up to you as the expert to derive and analize the results.
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Also a good point. In fact, these values should always be recorded as part of a routine maintenance program for future reference.
 
mikehughes8 said:
You dont need a megger that has a built in DAR/PI function to determine the DAR and PI ratio.

PI (polarization Index) is simply the ratio of your 10min reading to your 1 minute reading. (It's dependent on equipment class but a ratio of 2 to 1 usually indicates a good result) IEEE STD 43-2000

DAR (dielectric absorption ratio) is simply your 60 sec reading / 30 sec reading
Anything below a 1 is an indication of a problem
Above 1.4 Excellent


You can do the math yourself if the customer is requesting these values for some reason.
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No one said the customer was asking, and no one said you needed the PI/DAR function on the meter to figure it. I am used to factory work where we kept excellent documentaion, and trending was golden. IR scans and the such were pertinent. We always had scheduled down time maintenance. No one said you had to stand there while PI testing was being done either:wink:
 
iwire said:
Yes. .................
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Iwire take your new meter and practice. Take readings of different motors, cables etc . The first insulation tester that I bought was a tif IT 990 500v/1000mohms . It's a very simple to use analog tester but there were no instructions as to what type of readings that I should see when doing insulation testing. The first job I used it on was to check some long 500kcm feeders. I got some readings which I had no clue as to what they should be and was concerned about powering up. I have a 1507 fluke which I like but like anything it takes practice and knowing your meter. The information that is on this thread is very helpful. I wish that it would have been around when I bought my first tester.
 
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