|
Tinned wire
I realize that this might be a prompt for lots of argument but anyway....
I have just started rewiring the 12V side of my boat. While ripping out the miles of cable that seemed to power big blobs of ancient insulating tape I have noticed that the continued wire seems to have survived well. i.e. the boat is 20 years old and the original stuff is which was mainly continued is fine. I can see no signs of corrosion even after stripping large lengths. The insulation is a different matter in some cases. It is in a poor state, especially were it is exposed to heat or sun but that is a different issue. So the question is: Is tinned copper really necessary? It is more than twice the price of pure copper and has the same insulation! I am prepared for quotes from various recommendations and standards (many of which I have read) but what I would really like is some real empirical engineering info here. I have been involved in standards bodies and know how they work. Good ideas can very easily become mandatory requirements because it could be critical in some obscure cases. I was trained as an engineer which is to say I can live with the concept of good enough for purpose. If the life expectancy of pure copper is half that of tinned and tinned will last 30+ years, I can live with having to change the wire again in 15 years. Steve |
"Steve" wrote in message ... I realize that this might be a prompt for lots of argument but anyway.... I have just started rewiring the 12V side of my boat. While ripping out the miles of cable that seemed to power big blobs of ancient insulating tape I have noticed that the continued wire seems to have survived well. i.e. the boat is 20 years old and the original stuff is which was mainly continued is fine. I can see no signs of corrosion even after stripping large lengths. The insulation is a different matter in some cases. It is in a poor state, especially were it is exposed to heat or sun but that is a different issue. So the question is: Is tinned copper really necessary? It is more than twice the price of pure copper and has the same insulation! I am prepared for quotes from various recommendations and standards (many of which I have read) but what I would really like is some real empirical engineering info here. I have been involved in standards bodies and know how they work. Good ideas can very easily become mandatory requirements because it could be critical in some obscure cases. I was trained as an engineer which is to say I can live with the concept of good enough for purpose. If the life expectancy of pure copper is half that of tinned and tinned will last 30+ years, I can live with having to change the wire again in 15 years. Steve If the ends of the wire can be sealed from moisture then non-tinned wires will work fine. I've seen corroded wire up more than a foot under the insulation. If tinned wires is used then one can use crimped connectors without sealing the ends. Doug |
Steve wrote:
I realize that this might be a prompt for lots of argument but anyway.... I have just started rewiring the 12V side of my boat. While ripping out the miles of cable that seemed to power big blobs of ancient insulating tape I have noticed that the continued wire seems to have survived well. i.e. the boat is 20 years old and the original stuff is which was mainly continued is fine. I can see no signs of corrosion even after stripping large lengths. The insulation is a different matter in some cases. It is in a poor state, especially were it is exposed to heat or sun but that is a different issue. So the question is: Is tinned copper really necessary? It is more than twice the price of pure copper and has the same insulation! I am prepared for quotes from various recommendations and standards (many of which I have read) but what I would really like is some real empirical engineering info here. I have been involved in standards bodies and know how they work. Good ideas can very easily become mandatory requirements because it could be critical in some obscure cases. I was trained as an engineer which is to say I can live with the concept of good enough for purpose. If the life expectancy of pure copper is half that of tinned and tinned will last 30+ years, I can live with having to change the wire again in 15 years. Steve I had a similarly aged boat and the older wire varied a lot when removed. Some of the wire was black with corrosion, some was just a little dull, and some was shiny. More exposed wire, or wire where wicking from outside fixtures was possible tended to suffer more. Is tinned wire necessary? Probably not inside the boat for non-critical systems like cabin lights. For instruments, and navigation lights I'd say bite the bullet and use tinned wire. But do shop around. Many makers of tinned wire sell spools of wire for a lot less than Ancor at the local West Marine! One fellow regularly sells on ebay. Oh, on my boat all new wire is going to be tinned. Thankfully the electrical system currently consists of 4 lights, 2 nav lights (tricolour and masthead), a VHF, GPS, and depthsounder. It's rather spartan right now in the electrical department. Evan Gatehouse |
One thing I have noticed after working with several brands is that marine
grade wire is built up from much smaller strands than the standard wire you get at Home Despot. That makes them more flexable and less prone to fatigue breaks. If you do some looking you can find some great deals of marine wire. I figure I have more than a mile of wire in Rutu and have never paid much more than 50% of list price. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
Hello Steve,
You have my sympathy. Getting the quantitative data you're looking for seems near impossible. To my understanding, admittedly subject to recalibration, neither the USCG nor the ABYC standard requires tinned copper conductors. The ads often read "our tinned copper wire meets ABYC standards" suggesting that tinning is part of the standard, when the conformance reference is technically to stranding, insulation, and color! We know that tin oxidizes more slowly than copper, and that the copper oxides that form when copper corrodes are non-conductive. Beyond that, all I can find are anecdotal and largely unscientific reports, and the "tinned copper reduces corrosion" mantra. Good luck Chuck Steve wrote: I realize that this might be a prompt for lots of argument but anyway.... I have just started rewiring the 12V side of my boat. While ripping out the miles of cable that seemed to power big blobs of ancient insulating tape I have noticed that the continued wire seems to have survived well. i.e. the boat is 20 years old and the original stuff is which was mainly continued is fine. I can see no signs of corrosion even after stripping large lengths. The insulation is a different matter in some cases. It is in a poor state, especially were it is exposed to heat or sun but that is a different issue. So the question is: Is tinned copper really necessary? It is more than twice the price of pure copper and has the same insulation! I am prepared for quotes from various recommendations and standards (many of which I have read) but what I would really like is some real empirical engineering info here. I have been involved in standards bodies and know how they work. Good ideas can very easily become mandatory requirements because it could be critical in some obscure cases. I was trained as an engineer which is to say I can live with the concept of good enough for purpose. If the life expectancy of pure copper is half that of tinned and tinned will last 30+ years, I can live with having to change the wire again in 15 years. Steve |
In article , chuck
wrote: We know that tin oxidizes more slowly than copper, and that the copper oxides that form when copper corrodes are non-conductive. Beyond that, all I can find are anecdotal and largely unscientific reports, and the "tinned copper reduces corrosion" mantra. Good luck Chuck also be advised that Copper wire in the presents of Battery Acid fumes corrodes extremely quickly into copper sulfate, (Blue Powder) and that doesn't conduct electricity very well at all. The tin plating provides a good protection from this type of corrosion, the same as it does for Salt Water vapors. Bruce in alaska also a retired chemist, from way, way back...... -- add a 2 before @ |
Good point but unfortunately the only wire of sufficient conductor area
(16+mm^2) I have been able to find that goes anywhere need the batteries is just untinned copper. In this case I have used welding cable because it has better insulation than other stuff I have found. I have also sealed the ends well. If the stuff I am talking about here (1-2 mm^2 from the dis panel) is getting battery fumes I am in real trouble! Bruce in Alaska wrote: In article , chuck wrote: We know that tin oxidizes more slowly than copper, and that the copper oxides that form when copper corrodes are non-conductive. Beyond that, all I can find are anecdotal and largely unscientific reports, and the "tinned copper reduces corrosion" mantra. Good luck Chuck also be advised that Copper wire in the presents of Battery Acid fumes corrodes extremely quickly into copper sulfate, (Blue Powder) and that doesn't conduct electricity very well at all. The tin plating provides a good protection from this type of corrosion, the same as it does for Salt Water vapors. Bruce in alaska also a retired chemist, from way, way back...... |
All,
Thanks for the replies. It should mention that just about all the wire I am working on at the moment is internal to the boat. I think I will continue to use the untinned wire (bargains on marine cable are not common in NZ) but seal the ends as suggested. I am aware of the issue with fatigue if the copper is too thick and so will use something with lots of thin strands. I also solder all the small crimp connectors as well as crimp them which I believe will offer some protection. For the nav lights (front, back and mast) I an leaving the existing wire in place as it is tinned and in excellent condition. Thanks again, Steve |
|
"Steve" wrote in message ... All, Thanks for the replies. It should mention that just about all the wire I am working on at the moment is internal to the boat. I think I will continue to use the untinned wire (bargains on marine cable are not common in NZ) but seal the ends as suggested. I am aware of the issue with fatigue if the copper is too thick and so will use something with lots of thin strands. I also solder all the small crimp connectors as well as crimp them which I believe will offer some protection. From what I have read, solder and crimping is not a good idea. Soldering is not neccesary when using a proper crimp connector. Soldering has a number of drawbacks. A good crimp connection that is sealed against moisture is about as good as it gets. For the nav lights (front, back and mast) I an leaving the existing wire in place as it is tinned and in excellent condition. Thanks again, Steve |
| All times are GMT +1. The time now is 01:12 AM. |
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 BoatBanter.com