Black Wire Desease
10-15-2002, 04:26 PM
#1
Senior Member
Thread Starter
Black Wire Desease
This is a chemical reaction and not preventable except by being sure that you never have a nicad battery that outgasses or leaks. In my many years of observing this, it has only occured where a cell has been abused and the vent has blown (caused usually by overheating the batteries on charge or discharge) or, in the case of old NiCad wet cells, outgassing due to overcharge. Once detected, the only cure is to replace the infected wire in its entirety along with replaceing the defective cell(s).
11-05-2002, 05:10 PM
#2
Black Wire Desease
In some cases black wire is caused by the insulation on the wire. At the exposed ends atmospheric moisture reacts with compounds in the vinyl and attacks the copper. Fumes from vented batteries also cause damage. You can minimize the fumes by not using fast chargers and being careful not to overcharge with standard chargers. Battery venting isn't automatic with fast chargers but it is more likely and more severe when it occurs. The oldest NiCads I have invariably are the ones that have never seen a fast charger.
11-08-2002, 01:23 PM
#3
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Black Wire Desease
I hate to dissagree with Lady Flyer (she is almost always dead on with all topics) but I do dissagree with the insulation causing black wire disease. I think that, if you check closely, black wire disease is ALWAYS associated with NiCads and ALWAYS with just one terminal. I have never been able to find a case of black wire disease with any type of insulation when it was not connected to a NiCad battery. This is over a coarse of more than 30 years of interest in this sort of thing (I have always been very interested in failure analysis of all things related to electronics and electronic assemblies since that was my advocation). I have never found it possible to create black wire disease in any other manner than when connected to NiCads and have found it with all types of insulation, and where no insulation was involved. If anyone has evidence to the contrary, I would be very interested in obtaining it. Thanks, Rodney
11-08-2002, 09:37 PM
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Black Wire Desease
I've seen black wire corrosion through an entire spool of wire that was never near a NiCd. It was an older form of the vinyl insulation that used to cause the problem. To my best understanding... that formula for the insulation was discontinued several years ago. (for some reason... the black dye used was the culprit... the other colors didn't have the problem.)
11-09-2002, 03:42 PM
#6
Black Wire Desease
Some of the older vinyl insulation used plasticizers thet would react with air pollution of many types and give off gases rich in chlorine and ammonia. The gases would then attack the wire. The new wires are far more stable but I think it is the potasium hydroxide vapors are too much for the copper. It probably attacks the vinyl as well.
I too have found old spools of wire that have gone black It (black wire) also occurs in marine applictions and to a lesser degreei n old cars ,motorcycles etc . I'm sure the chemistry is well understood by folks in the wire industry. A lot of the low end stuff from Asia being brought in by the mass marketers bears a close look from time to time as the insulation may have some of the same qualities as the old stuff we dumped years ago !
Thanks !
BTW, It is usually found at the POSITIVE terminal because the vent is at that end ,but not always. It also appears around Lead acid batteries ,Alkaline and Carbon-Zinc batteries ,leaky ones.
I too have found old spools of wire that have gone black It (black wire) also occurs in marine applictions and to a lesser degreei n old cars ,motorcycles etc . I'm sure the chemistry is well understood by folks in the wire industry. A lot of the low end stuff from Asia being brought in by the mass marketers bears a close look from time to time as the insulation may have some of the same qualities as the old stuff we dumped years ago !
Thanks !
BTW, It is usually found at the POSITIVE terminal because the vent is at that end ,but not always. It also appears around Lead acid batteries ,Alkaline and Carbon-Zinc batteries ,leaky ones.
01-03-2003, 12:34 PM
#7
Black Wire Desease
Quote
<hr>Originally posted by: Rodney
Thanks FHuber, my apology to Lady Flyer, she appears to be correct again. Does anyone else have any similar experience?<hr>
Yes, I have. I salvaged a 20 foot piece of coax (very flexible) that was on my father-in-laws old VCR. It was an early VCR that had a remote on a wire. The remote contained several switches and resistors, no NiCds. When I stripped it, to my surprise, it had the black wire disease on both the center conductor and the shield. This wire had never been close to a NiCd. Yes, the insulation was black.
Over the years (48 or so) I have encountered other black wire disease situations where NiCds were not involved.
Dan
