Green Build-up on Wiring

[PhilDuhs]

Hi,

I recently noticed some green, gritty powder coming from behind the panel that contains my windlass wiring and upon opening the panel saw a lot of the green build-up on 2 of the cables/connections that power the windlass.

Can anyone tell me what this is, why it happens and how to prevent it from recurring - I'm sure it's not good for the wiring or the connectors.

Is this a common problem and does it indicate any sort of bigger electrical problem that I should be looking into?

All help appreciated!

Phil
S/Y 37 Rocks

[the_alpine]

As I'm sure you're aware, that's called corrosion. Pretty normal occurrence on boats, but steps need to be taken to treat/prevent it. If left long enough, that can creep up your wire inside the insulation. More corrosion=more resistance and eventually, failed connection.

Clean it up and dab some anti-corrosion on it. While you're at it, check all of your other electrical connections.


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[the_alpine]

Also, it looks like maybe you have a leak dripping onto those wires.


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[PhilDuhs]

Thanks - do you know of any special solution/aerosol that can be sprayed onto the corrosion to dissolve it safely or is it a case of scrubbing/sanding it off?

[JPA Cate]

Scrape it off. File it clean. That one connecting eye may need to be replaced, you may find that there's not enough "meat" left on it for a good connection. I'd look seriously--as suggested above--for the salt water source. If it is really dry where the boat is, you're looking for dried salt crystals and a stain above the green corrosion.

Ann

[a64pilot]

It's copper oxide, look at a copper roof and you will recognize that color.
I'd strip the wire back until I got clean copper wire, if you can't do that, and if there is much of the oxide, I'd replace the wire.
Waterproof the terminals with the kind that heat shrink and have hot glue in them to seal them and or I have had good luck by covering anything exposed with silicone grease.

[Dsanduril]

yep, copper oxide. In smaller wiring we try to use tin-coated wiring to prevent, but in windlass size wiring you usually get bare copper. If the corrosion is just on the terminals clean them well with a non-rusting tool (a wire brush can cause other problems - emery cloth, brass brush, etc.). Then coat them with a corrosion inhibitor before installation. You can find inhibitors at any hardware store in the electrical section, something like either of these:

http://www.specialized.net/Specializ...-4Oz-2266.aspx

http://www.specialized.net/Specializ...16Oz-2264.aspx

[exMaggieDrum]

As noted, you want to get rid of all the existing copper oxide, after getting rid of as much water/humidity as possible. You can get large cable which are tin coated and it would be highly recommended or this application. It is much more resistant to corrosion and prevents its creep up the wire.

I use a small wire brush - stainless steel or brass - to clean the corrosion off. You want to get it all.

When you cut back to good, clean wire, or replace the wire completely, use heat shrink with adhesive lining in it. It seals much better and will last longer. Don't use non-adhesive heat shrink unless that is all you can get. For the big cables use heavy duty HS and don't scrimp on the length of it. you want to cover enough of the insulation that it will resist pulling off even if you bend the wire.

And coat the terminal with dielectric grease/compound as noted above. You don't need gobs of it, just enough to coat the terminal and crimp. Don't use it inside the crimp/lug. And use closed-end lugs for the large cables, not the open-end barrels. The little one you can either use crimps that are heat shrinkable or heat shrink them and coat the open end of the crimp. You should always do professional quality crimps on the large cable lugs - not the "hammer" type. You may have to get a special tool or have some one do them for you. Whatever you do - no solder. Some may disagree - don't listen.

What you have is not uncommon.

[Zil]

If you have to replace the cable, use tinned marine wire. Available in all awg sizes. Do your batteries vent to this area?

[Cheechako]

It's cuprous oxide... the outer layer that accumulates on copper. Clean it off good and shiny, then after reattaching spray with a protective coating. For large cables maybe CRC 5-56
SS wire brush, file or etc will clean it.

[hellosailor]

Green, copper oxide, the result of water or moisture getting on the cables. You may be able to clean it off but usually you'll have to lop off the cable until you get to clean metal, hoping there's enough slack to do that. Then make sure to use an anticorrosive and if possible to seal the new end fittings (i.e. with liquid vinyl, which either seals them well, or hides new corrosion if you haven't sealed them well) and of course, seal the leaks. Silicone grease is your friend, it keeps water out.


If you don't have enough slack, you can always cut them back to a hard mounting point (bulkhead, overhead) and then tie in new cable pieces. Tinned wiring resists corrosion much better. Worth every agonizing penny it costs.

[PhilDuhs]

Thanks for the many tips. The batteries don't vent to this area but it's located immediately behind the anchor locker (which makes sense as these are the cables to power the windlass) so I expect some moisture has got into this area over time.

I'll see how well I can clean the existing cables and connections and how much slack there is to shorten the cable and start again ...although I don't think Beneteau will have given me anything more than the absolute minimum amount of cable they needed to!

Out of interest - what difference does it make if the batteries had vented to this area (or other area where wires have similar corrosion)?

[sartorst]

I usually have enough wire to cut the end off and start over and have not tried this trick on wiring but works like a champ on battery cable ends that are very corroded and that is to place the end in a cup of plain water and wait about 10 15 minutes depending on condition You wont believe how clean it will get it

[zeehag]

as they have stated is cuprous oxide. you NEED to go thru ypour panel an d examine all connections and clean and redo em all. while you are at that, check integrity of all wiring an d also the distal connections.
have fun .

oh yea-- find the leak that is wetting your panel and fix it.

[exMaggieDrum]

Originally Posted by PhilDuhs

Thanks for the many tips. The batteries don't vent to this area but it's located immediately behind the anchor locker (which makes sense as these are the cables to power the windlass) so I expect some moisture has got into this area over time.

I'll see how well I can clean the existing cables and connections and how much slack there is to shorten the cable and start again ...although I don't think Beneteau will have given me anything more than the absolute minimum amount of cable they needed to!

Out of interest - what difference does it make if the batteries had vented to this area (or other area where wires have similar corrosion)?

Wet/flooded batteries are the worst (but sealed batteries also do it to some extent) will vent some corrosive gases. Hydrogen and sulfuric acid being the common things. Sulfuric acid is normally a liquid but it gets in "solution" in the gases that come out. Flooded batteries shouldn't be put in locations next to motors and electronics for this reason, and any compartment should be vented so gases don't get trapped and build up. Under a settee (common) is not usually a problem if there are louvers or vent holes in the woodwork.