Sometimes Practical Sailor is Not So Practical...

[Ross]

Duplex generally refers to a 2 conductor jacketed cable

In the electrical trades they label as to wire size and number and type of conductors. Example is 14-2/G Which means 2 insulated 14 gauge conductors with a bare ground. It can also be 14-3/G or 14-4/G. You buy what you need. The theory of osmosis can be checked easily by placing a loop of wire into a corrosion solution (salt and vinegar) and letting it sit for a week and then stripping the insulation. Capillary action is the more likely problem and that can be checked by placing a cut end into some colored water or oil and leaving it for a week and then stripping the insulation.

 

[Maine Sail]

Ross..

Having been a manufacturers rep in the hydronics industry during the era of oxygen permeated radiant tubing I can assure you it can and does happen! This oxygen permeation, through the, at the time rubber based radiant tube, caused many, many system failures and millions of dollars in damage. It was this oxygen permeation issue that caused the industry to develop oxygen barriers and PEX tubing!Here's some info copied from the RPA of which I used to be a member..Definition: The ability of oxygen molecules to pass through a material due to the material's molecular structure and a difference in the partial pressure of oxygen on each side. Relevance: Oxygen can be introduced in significant enough quantities that, when combined with other factors, might cause unacceptably high rates of corrosion on ferrous metal components.

 

[Ross]

Of course in this discussion we are dealing with

copper and not iron alloys. Generally oxygen is not a major factor in copper conductors as demonstrated by the millions of miles of bare telephone wire that was hung before multi-pair cables came into use. The early telephone cables had paper insulation and a lead sheath. The interior wiring was insulated with cotton. It was with the advent of plastic that the insulation changed.Still I believe that a prudent person would use tinned copper conductor in a boat.

 

[RichH]

Ross --- take a deep breath

What Maine states about vapor pressure permeability with almost all polymers is most certainly true. In the case of bare copper wire ... how come you dont see post and ferrule runs of lines anymore? The answer is that the copper reacted immediately with the atmospheric acetates and almost immediately formed various types of 'verdigris' which retarded the capacity of the wire and especially formed corrosion at the connections - and had to be totally replaced OFTEN. The same formations still occur even with 'insulated' wire; only now the 'still permeable' polymers retard the verdigris formation but ultimately will still have to be replaced. An equivalent example would be stripping non-tinned wire, let sit for few days before soldering the connections and see what happens ..... you cant because of the immediate oxidation and acetate formation/deposition. No matter what you do 'you still cant fool Mother Nature' ... as chemical equilibrium and entropy will always win-out in the end. Tinning of the copper wire, although not perfect, versus CopperAcetate, etc. formation is still the best 'retardant' .... unless you want pay for gold plating.

 

[Ctskip]

Being of average intellect

(some will dispute that). My question is. Isn't it the jacket, the wire is in, the culprit here? And not the wire itself? With that being the case, with a quality jacketed wire, (one that wont absorb moisture) what advantage does a tin plated wire have over a non-tinned wire? It seems to me, any fault seems to be in the connections and the jacket itself and not in the wire. Am I way off base here? Secondly, How/where does one find a quality jacketed wire for use on our boats? One that won't absorb moisture, no matter if it's under water or over head. Who do you trust? Thanks Keep it up, Ctskip PS; Ross, I have been using 3M liquid rubber for many years now ,also.

 

[Fred Ficarra7897]

Maybe I missed it

but no matter the wire or the terminal type, the very best way to protect your connections from corrosion is to give each joint a spray of silicone. Yep, it'll last longer than boat. And I noted that the only soldered joint, mentioned above failed because it broke. I've read several times over the years to not solder for that very reason.

 

[Capn Dave]

As a (retired) electronic engineer

that has been in the marine industry for over 26 years, moisture does wick through a conductor. No ifs ands or but's. Don't believe it? Try this little experiment at home kiddies.Put some water in a glass.Add salt.Strip back about 1 inch of the insulation from copper wire tinned or otherwise and suspend the bare wire into the saltwater solution.Sit back and watch. This is the easy part. In about 2 weeks salt will come out of the other end of the wire, and form crystals.PS is correct in their statement. It is a fact no magic involved.If you seal the ends of the wire, you will have no problems. Good call Ross and Don.Fair Winds Cap'n Dave

 

[Ross]

They (the people that manufacture insulated wire) can meet any requirement

that you have but always at a price.The telephone company went to multi pair cable because they ran out of space on the poles for open pairs and because the open pairs required that they be self supporting. Corrosion was not a determining factor.

 

[BobM]

Another vote for tinned wire

I had to replace the bilge pump on my Lancer 25 last year. I was appalled to find that the prior installation used untinned wire that was black under the insulation from end to end of a ten foot run. Furthermore, I ended up redoing every connection on the breaker panel they were such a mess. Even the job I did wasn't perfect...I didn't know there were special terminals for use with shrink wire wrap. I did change all the connectors (crimp on) and shrink over all the crimps though.By the way, I gave up on PS...there was practically nothing in the issues I was interested in buying once I decided on a bottom paint. I also gave up on Consumer Reports...reviews so thorough that what they review isn't even on the shelves anymore. By the way, they have sold my personal information more than ANYONE on the planet earth. I know that for sure since they insist that my middle initial is a C...its not...I haven't been a subscriber for five years and I still get floods of junk mail for some guy with a C. for a middle initial!Bob

 

[Maine Sail]

Capn Dave??

So are you saying ALL wire insulations are an oxygen barrier and totally oxygen proof?

 

[Big Windy]

PS

I subscribed to PS for a number of years...during the time they went from black and white to color. After a while they start repeating themselves, there are only so many item you can test and retest. Bottom line, they are way too expensive for what you get...I stopped subscribing and have not missed them.

 

[Capn Dave]

Main Sail

What kind of question is that? I never mentioned oxygen. Remember your dealing with an engineer :>)Fair WindsCap'n Dave

 

[Maine Sail]

Dave you said..

Quote: "If you seal the ends of the wire, you will have no problems."This means no oxygen or moisture can permeate the insulation and oxidize the wire? No? Maybe I misread your meaning. Sorry if I did..

 

[Ross]

Maine Sail. Oxygen is not a problem with copper.

If it were then all of those bronze pieces on our boats would be in trouble. As I pointed out the telephone and telegraph companies ran millions of miles of bare copper wire for a hundred years before they switched over to multi conductor cable to increase capacity and to save material. The copper pipe in houses never goes bad from the outside. Oxygen by its self in not a problem with copper.

 

[Mac]

Mainsail, I agree

When I wanted to add a new bow light on my Macgregor 25, I looked at the phone cord wire and the copper end was black. So I decided to cut back a few inches so I could find some clean copper wire, still black. I cut back 2 feet, still black. I ended pulling the whole wire out, about 20 feet, and tried to hook up a simple 12 volt light using the wire and guess what!! nothing! no light. I looked for nicks, nothing, the wire looked good but would not conduct. So I ended up stripping all the wire out. I'm new to sailing and I'm a DIY. I didn't know what tinned wire was before I did this replacement of all my wire. I did use nontinned wire, shrinked wrapped everything and used crimped connectors. I hope it lasts for awhile. I even used trailer 4 wire for putting a mast light and a streaming light on my mast. Will it last? who knows.. But I agree with Main sail that the copper will oxidize through the jacket. I do enjoy reading PS because I am new and I'm intrigued with the articles. Good post!! Mac

 

[Tom S]

Maine Sail. I just read the PS article and I think you took the article wrong.

After reading your post I thought they wrote an article testing all sorts of wires and brands of wires. Thats not how it was writen at all. It was a letter written in by someone about their 25' sailboat. The person even mentioned "I am not using the boat that much and I don't intend a circumnavigation".After re-reading it a few times I think you missed the tone of the article. Sure PS shouldn't be encouraging the average boating DYI to cut corners on some important items but in this case it was not a full blown article on wiring but they were giving advice to one specific persons situation.PS didn't say un-tinned wire is as good as tinned wire, they said just the opposite ("Is tinned wire better? Well, it is more corrosion resistant,") They just intimated that one needn't panic and rip out all ones un-tinned wire. As you stated they said "but the truth is, the un-tinned wire has been used for years and provides a more-than-adequate service life in most cases" . Maine Sail, you know that is true. How many old boats are still out there sailing with un-tinned wire? We all know lots. Is is as good or last as long as untinned wire? Hell no ! Would I put un-tinned wire on my boat? Hell No. When I do a project I want to do it once and not have to worry about it or revisit it in 10 years. I want everything to be working long after I'm gone. I know that is not always possible but I strive to Maine Sail I think I can speak for most here that any of us would be very happy to purchase a boat you once owned. We know the systems you put on your boat would be as good as it could have been done at the time, that doesn't mean that one can't own and enjoy a boat in relative safety that doesn't have all systems gold plated.I hear you on this article and PS normally is very conservative with regards to things for ones boat, but I am giving PS a slight pass on this reply to a letter.

 

[Ross]

This is for everyone who is distressed about oxidized copper wire.

Copper cables are easily joined because copper does not form a tough non-conducting oxide on its surface. The oxide film that forms is thin, strongly adherent and electrically conductive. A large proportion of the wire and cable used in buildings, involve single-conductor connections, for which copper's resistance to creep is a distinct advantage.http://www.coppercanada.ca/publications/pub27e/27e-Section2.htmlAs everyone says don't take just one person's opinion as the final word on a subject.

 

[Tom S]

Ross, Good find

Very good information that I think very few of us here knew. I, like you, never though the "black" oxidation on the outside of copper reduced conductivity. I think the biggest area of concern is and always will be at the crimp connection points. What tinned wire ~does~ do is help protect the crimp connection points from not just oxidation but from deteriorating to the point of corrosion. Which is a ~real~ problem. We know we've all seen it.Thats why I think PS letter to that person was not far off base. They claimed un-tinned wire ok, but the most important issue was having a well sealed crimp connector. Like they said "Standard crimp connectors will not do the job"

 

[Ross]

Tom S, A long time ago I crimped a connector to

to a piece of 10 gauge stranded single conductor insulated wire and dropped it into a jar of water with some fertilizer in it. I left it for about a month and the bare wire turned green and mossy. I dried the piece and sawed through the crimp with a jeweler's saw. With a 10X magnifier I could see no sign of corrosion in the wires in the crimp. The other end also had a crimped connector but that was dipped in 3M liquid rubber tape. That end was in the came condition as when I started.

 

[Tom S]

Ross, I think different conditions will reveal different results

I think for noticable deleterious results one would need more than 1 month. Also the connection inside the crimp are probably not where the corrosion starts, but on the pinched crimp interface connections on the outside. I also think electrical current and air (oxygen) will accelerate corrosion, not just wire under water.I want to reiterate, I am all for tinned wire and I do think its superior. I just wouldn't panic or overly worry if I had un-tinned wire and good sealed crimps