Make Discolored Black Gigbag Black Again

• #1

I'm tidying up the wiring on a Jeanneau yacht I recently purchased and have plant three wires where all the copper stands have turned black inside the insulation / sleaving. The boat was first sold in 1988 and I believe this is the original wiring. The copper strands haven't been tinned and the wires in question go to internal and external devices (lights).

Has anyone out there any ideas regarding what may have caused the copper strands to plough black?
What does it indicate - should I replace the wires?
What should I use to make clean the strands at the concluding points if I don't modify the wires entirely?

I've stripped back the wires nearly 30cm and found 2 out of three wires even so have blackness strands. On the wire that feeds the internal lights the stands are still bright copper in colour - no black discolouration nor any sign of oxidation. The color of the insulation is white on one wire, dark-brown on some other and black on the other.

Any ideas / advice? /forums/images/graemlins/smile.gif

• #2

The black is caused by salt water having seeped between the wire and the insulation. Modify the wire.

• #three

Cheap wire. Should be tinned, but more expensive.

• #4

Cloven

Active member

Joined

17 October 2003

Messages

2,231

Location

Scotland

The black layer is Copper Oxide. It is quite common where non-tinned wire has been used and is due to corrosion in a salt-water environment

Every bit for cleaning the strands, you lot simply need clean the office which will come into contact with a terminal etc. What I practise is splay out the wires and give then a light rub with fine sandpaper. This will remove the black layer and the shiny copper will be revealed. Then, twist up the wires again and fix. It may assistance if you solder them at this bespeak simply others may differ.

Hope this helps

• #5

Liberal application of vaseline or, even better, electrical protection spray, volition reduce how quick it goes black.

As mentioned, bare copper cables are much cheaper than tinned copper. IMO use normal copper cablevision, and supplant as necessary. Not much consolation though if your boat is a product boat with 'loomed' cable assemblies :-(

• #half-dozen

Thank you

What confused me is that I expected the salt water effect to create a white / grayness oxide powder. Any thought why the copper hasn't produced a white powder oxide and instead turned blackness?

• #7

The clean choice sounds preferable to re-wiring - removal of glued healinings isn't very highly-seasoned! Shall try the fine sand paper approach.

Many thank you once again.

• #8

I would have expected wiring to turn blackness due to heat rather than seawater which would cause copper to corrode to green copper chloride.

Whether that copper oxide black is a problem depends on the extent of it. A lighting load will potentially warm wires every bit it may be on for a long period. It may exist necessary to increase the wire size if it is likewise shut to the wire'due south capacity and is overheating. Excluding oxygen by using Vaseline or similar may forbid the blackening around terminals.

Tin the exposed ends with solder to protect from table salt.

• #ix

The rut theory is ane that did occur to me every bit a possible reason just the insulation shows no sign of having been excessively hot in the past.

• #10

Just found a website that discusses reactions of copper and it mentions copper turing black without awarding of oestrus. I'yard inclined to believe the black discolouring is a chemic rather than a thermal issue - but not sure what chemic reaction is taking place and its consequence on the conductivity and insulation properties of the wire?

• #eleven

The black oxide isn't specific to seawater. Motorcycles of a similar age to the boat mentioned oftentimes endure from the same problem.
I'm no chemist, and other forumites volition doubtless accept more administrative views, just a bit of googling sugests that the blackness oxide is copper oxide (CuO) which is formed when cuprous oxide (Cu2 O) is heated -- is it might be when it'south asked to perform as an (inefficient) conductor. Cuprous oxide is red -- sometimes called the red plague.
Similarly, copper carbonate (the familiar green stuff) decomposes to the black oxide when heated.
Too as embrittling the cable, the oxide is highly resistive relative to elemental copper and besides prevents tinning.
I've used enough of tinned cable and, to be honest, it's far from immune from oxidisation. In fact -- and this is an utter no-no for boat use -- the least oxidation I've encountered on sometime cable was on domestic twin-and-earth (installed by a domestic electrician, tight sod!). The thick strands seem far more resistant to corrosion.
The lesson may be that starting off with a good crimp or tinning (most authorities seem to favour crimping over tinning) reduces local hot-spots which might encourage oxidation. Be interesting to hear from anyone with expertise in this field.

• #12

tyce

Well-known member

Joined

half-dozen Jan 2004

Messages

1,509

Location

cumbria

in reply to 2Tizwoz,
are you bonkers, if i had electric circuitry heating to the extent of it blackening i would be seriously worried.
i remember you can happily believe it is oxidation

• #xiii

Calm downwardly Sean!

I believe most people accept that the black discolouration is acquired past oxidation. Certainly on all the boats I've had at that place has never been whatsoever overheating and all the wiring ends up black.

The only way of stopping it is to use tinned wire which is and so expensive and to my mind unnecessary

• #fourteen

Thanks folks.

Sounds like this is the norm that many tolerate without rewiring.

With all the other wires I've but been crimping, only for the blackened wires I was thinking I may clean then tin can the stripped wire ends so crimp - will this work or is tinning and crimping a no-no?

• #15

Tinning and crimping would probably result in lest contact expanse between copper and crimp, and introduce another (corosion-inducing) metal into the equation.

It is a good thought to clean upwards the cores before crimping, merely then afterwards liberal vaseline or other sealer to seal the join and prevent further ingress of boiling air.

• #sixteen

Alrob

New fellow member

Joined

19 Jul 2005

Letters

ane,042

i agree with your last comments as I know that in my radio gear for my R/C models after a while one of the wires from the Rx bombardment goes black (cant remember which one ) & has to exist replaced - pitiful I cant remember all the tech info for this - seem to call up it has something to do with letting battery level go depression - but not 100% sure

cheers

• #17

It is chosen Negative corrosion, is somewhat slowed downwards if the conductors carry an Ac supply. salt atmosphere does not assistance, it pays when using untinned conductors to crimp and make full crimp with solder, this method ensures that minimun resistance at the connection. Once sailed on a DC transport that had a fire in a winch house, outset port ii winches failed due to this problem,

• #18

An unfortunate side event of blackening is that it has an insulating effect, and on some non marine type connectors , such as the chocolate box type so beloved by amateurs, will result in failure of the connection. It LOOKs fine, only the current 'aint going nowhere!

As has been suggested, plenty of protective vaseline or battery temrinal jelly is the simple way to stop it. A less messy style is to spraya couple of coats of PCB Lacquer from Maplins over all the connectors to seal them. The only problem then is if you want to modify the wiring it doesnt come off hands except with special solvent or a soldering iron!

http://www.maplin.co.united kingdom/module.aspx?ModuleNo=29005&doy=2m12

• #nineteen

Besides equally providing an insulating layer, the oxide coating has no force, and on thin wire this will hateful bad news equally there isn't much else left of the wire. Would not consider remedying but replace.

• #xx

I agree that this is a chemical process and oxidation. My experience is that estrus promotes the oxidation procedure. I have noticed similar oxidation for instance where a domestic hot h2o pipe turns black whilst the cold water pipe running alongside remains copper coloured.

I am non suggesting that the wiring is necessarily overheating to the extent of damaging the insulation or becoming excessively hot but rather that cabling running warm may be affected in this manner.

What others have said concerning a terminal beingness a point at which overheating is liable to occur is my experience also even to the extent of melting the terminals and cables.

Tight clean joints making good contact and protected in the various ways described above from corrosion problems volition prolong the life of whatever wiring.

Wet ingress will create atmospheric condition which will promote corrosion.

mathewsandetter58.blogspot.com

Source: https://forums.ybw.com/index.php?threads/copper-strands-have-discoloured-black.107670/