# Distributed impedance fault



## Wiresmith (Feb 9, 2013)

i'm not sure what the fault is but if its an insulation problem you may be able to use an ohmeter or low voltage megger between the individual conductors. it about sounds like conductivity problem though, if that's the case i can only see testing it with both ends of the cable.

i would find out what the specific problem is with the cable you know is bad, whether its breaks or thin spots in conductors or something else. i'm interested to know what it is too if you don't mind posting if you find out


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## UncleMike (Jan 2, 2013)

Unfortunately I won't have access to the known bad cables unless further issues are reported by the end user. I'll see what diagnostics I can perform on the remaining boxed cable, but without knowing what exactly I'm looking for in such tests, I don't really know if I'll recognize it if/when I see it.

On the other hand, if I'm going to trash the remaining cable anyway,I could always throw a bottle of jacks on a 200+ foot length of it and test it as if it were installed. If I can learn something from doing that, it will be far more valuable than the cable itself.


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## splatz (May 23, 2015)

I hae the cableIQ tester too, I never saw that particular fault...

I would definitely toss any no-name cable. There is a lot of absolute garbage, mostly coming from China, with fake UL stamps. 

If you catch it at testing time, that's lucky. There is an excellent chance more will go bad. Hopefully the customer doesn't give you a bad time about paying for the time to troubleshoot and cost to replace. 

Some of the worst stuff was copper coated tin or etc., it came from some of the bigger bargain online retailers too, Monoprice was selling it, they claim they've gotten much more careful. 

The blue pair might be the most likely to fail because it's twisted the tightest, so marginal materials would break down in that pair and not others. Or it could just be crap.


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## joebanana (Dec 21, 2010)

That's why I only buy name brand cables (Beldin). Stuff marked "Made in China" has alway's proven to be crap.


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## UncleMike (Jan 2, 2013)

One of the boxes I had remaining had 120 feet left in it. I put a jack on each end and tested it - it passed. The other boxes had 400-500 feet left, and I had no interest in pulling enough cable out to make a testable cable. I chucked it all, plus all the other Chinese crap I had laying around, leftover from similar jobs (materials supplied by others). I now have probably $100 in scrap value in a garbage can, and some more room in my garage.


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## gnuuser (Jan 13, 2013)

low voltage megger would expose insulation faults easily.
on that note the winding machines that roll the wire for boxing tend to stretch the wire and insulation a bit (usually in the first 50 feet of wire)
but if they are doing it at high speed it may damage over 100 feet of wire.
if possible look for a supplier that will test the entire roll.
buying from a reputable dealer helps a lot 
buying from many off brand companies is a gamble at best.


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