Just yesterday it was like Christmas. I went to the mailbox and both Professional Boat Builder and Practical Sailor were in there! Which do I read first....
Anyway, to my point. After reading PS cover to cover I flip the back cover and there in bold print I see the headline "Tinned Wire Myth Busted".
Now I know as well as anyone that the ABYC does not specify the use of tinned wire, heck I own a copy of ABYC E-11, but to totally diminish tinned wires value in a boat is just plain foolish, and short sided, on PS's part.
Sure, there were many truthful points made but the entire gist of the article was to portray un-tinned wire as suitable for marine use because it "has been used for years" and "provides more-than-adequate service life", which they then never defined. Of course they did end that sentence with "in most cases" to cover their butts....
"By using heat-shrink crimp terminals or adhesive-lined heat-shrink tubing on conventional crimp connectors, you can effectively seal the ends of all the wire on your boat."
While I totally agree with PS's points about using heat shrink crimp terminals, I disagree that using an adhesive lined heat shrink over a NON heat shrink "conventional" crimp connection is a suitable alternative to an actual heat shrink connector.
In my experience, it is VERY, VERY difficult to find a piece of adhesive lined heat shrink that will:
1) Fit over the existing nylon insulation on the non-heat shrink connector as this is a rather LARGE diameter and becomes more than a 3:1 shrink
2) Shrinks enough, from the diameter needed to fit over the insulated crimp connector, to make a proper seal around the wires OD and to properly seal the terminal end.
Can it be done? Sure, but you will WASTE many pieces of expensive adhesive lined heat shrink and crimp connectors while attempting to make your "hermetically sealed" connection, yet failing to make a solid watertight seal that is easily replicated.
It is much easier, repeatable and reliable to just use crimp terminals designed and sold with the heat shrink already built in to begin with.
"Without exposure to moisture, or salt air, the un-tinned wire will last as long as the tinned"
I can't even begin to agree with any part of this statement without them giving further clarification. This statement as written is totally and 100% misleading! Why? First off all wire jacketing is NOT the same. Many boat builders used cheaply jacketed wire, including but not limited to, "lamp cord".
The photo bellow was taken just last night! I went to re-wire my shower sump and found some older DIY wiring that did not meet my standards. Long story short, I am now doing a major portion of my re-wire, that I had planned for this winter, now.
This photo illustrates why the PS statement above is, to say the least, MISLEADING and dishonest. I cut this piece of wire from the CENTER of a 15 foot run. The wire had been encased inside a glassed in PVC conduit and was NOT in the bilge but rather half way up the top sides and out of direct contact with moisture. As you can clearly see from the photo this wire is severely oxidized and has turned black in the MIDDLE, or about 7 feet in from the end, of the wire! This is ONLY due to one thing, moisture, oxygen & humidity transmittance through the JACKET of the wire..! The flash and the stripping action of the wire actually made it look more like copper than it looks in real life.
"You'll need to strip back the wiring until you find clean, pink copper. Usually this requires stripping back no more than an inch or so if insulation."
LOOK AT THE PICTURE is all I can say...
You can't always believe what you read just because you read it in PS. Sometimes these authors don't fully investigate their own statements..
Cheap wire will oxidize and corrode THROUGH THE JACKET and MANY builders used cheap wire before the ABYC issued jacket ratings...! Even these UL/ABYC jacket ratings don't prevent and eliminate internal oxidation of the copper in all cases.
So yes even PS needs to do a BETTER job with their reporting and investigating...! Please read carefully!!!!
P.S. The factory wiring, not the DIY wiring, on my 29 year old Canadian Sailcraft is a bare copper duplex jacketed wire and is nice, clean and pink copper showing no oxidation.
The jacket on this FACTORY wiring, was, and is a top quality bare copper duplex wire that has very good insulation and jacket. What PS said CAN be true but they need to be very careful painting with a broad brush. A case in point would be factory wiring on my old Catalina 30 from the early 80's. This wire was totally oxidized throughout the entire boat! As I stated not all wire is created equal!
Oxidized Wire 7 Feet In From The Ends:
Middle of the Wire:
Top begin with, I enjoy your posts. They are well thought out and written up. I appreciate the input.
Now to the thread and my experience after pulling out 44 million miles of wire from a Tayana 42, and comparing that with tinned wire that has been standard on the boats I have owned.
I have found that non-tinned wire seems suitable on the interior of the boat. We have found very little corrosion issues on anything inside. The exceptions, for reasons I am not completely sure of, seem to be any (ANY) joint that was soldered. Anything crimped is fine - many crimps not having any heat shrink at all.
Now, as for the outside, it is corrosion-city. Soldered connections have failed or were about to fail. The water intrusion you have described seems well more than an inch, as they may have proposed. In most cases, by the time you pull off a suitable amount to get to non-corroded wire, the thing is too short and you either have to butt-connect/splice or re-pull. We opted for repulling, each time with tinned. We ONLY used tinned on the outside. I will never use bare copper on the outside. It does not hold up, in my opinion.
As such, my basic conclusions are that non-tinned is ok for down below, tinned only above deck or wet locations. Anything else fails over time. Also, never solder. They ALL seem to fail.
Just my opinions and experience.