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Tinned copper wire

T

terry_thatcher

Terence Thatcher
An issue has arisen among friends, How important is tinned copper wire on a boat? ABYC does not require it, but recommends it. Practical Sailor says as long as the end fasteners are covered in shrink tubing, it is not critical. When I add or replace wire, I always buy the tinned wire at a chandlery. Perhaps more important for my 43 year old Morgan, I think Morgan did NOT use tinned wire. If I cut or open some of the original wiring, it has turned black. But everything on my boat still powered with the original Morgan wire still works fine, including the things where I have seen black copper . Of course, nothing on the boat using untinned wire draws many amps. On the stuff that does, like the windlass and the Lectra San sewage treatment system, all the wire is massive tinned cable. For the water-maker and fridge, it is high quality tinned wire. I know some have rewired their boats, but except for the bow red/green that had bad splices, I have never had a problem. Comments and advice welcome. Thanks.
 
No, it isn't required. But I think it wrong to replace a wire and not use it. No boat the age our ours had tinned wire from the factory as it is a relatively new practice. I have had very minimal issues also, but have fixed many old wiring issues on a friends boat. Always at a splice or crimp connector. Corrosion on the surface of the copper along it's length will not harm much, as most of the cross section is still fine. But, at a connector, the corrosion prevents a good connection.

I would consider at least changing out some critical wire. I have rewired my mast, and the wires for it to the terminal block in the head, and my bilge pumps (which the wires failed) and repaired a few bad splices. The bow lights, but also the splice for the stern light failed. That splice is perhaps the most difficult spot I've worked in, zip tied tight to the hull deck joint under the the foremost leg of the stern pushpit. The aft cockpit locker (with the steering quadrant), all six feet one inch of me, including my feet fit in that locker, and it hurt being in there, bent all wicked wrong.

There are splices in the hanging locker across the head for cabin lights. Also zip tied tight to the hull deck joint, but slightly easier to get to. If the lights in your galley go out, that is the likely spot.
 
I've also gotten in the habit of wiring new stuff and rewiring with tinned wire. I also use dielectric grease on/in the connection fittings. I don't know if it helps, but it mnakes me feel better. Jim? Your thoughts?
 
I always re-wire with tinned wire too, having heard the advantages they make sense to me.

My guru (in addition to Warren and Jim!) is Nigel Calder. In his bible it highly recommends tinned wire and says it will last much longer. It doesn’t make any absolute statements, though, on necessity.

I hope you guys are all doing well? We are on a charter catamaran in the islands east of Puerto Rico. Currently Vieques. Awesome weather, sailing, with good friends. A nice break from Portland’s gray/wet winters.
 
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Tinned copper wire is wonderful stuff. But is it worth the money? If you use stranded wire, of any size on a boat and use a dielectric grease, such as Penetrox, to seal the strands of the wire where they enter into the insulation to prevent the creep of corrosion, before installing a Sta-kon or end fitting, you will protect the wire. That process will protect the wire as well as tinning. Why pay high prices, such as $1.50 per foot for #14 Awg tinned wire ( the listing for 10' of #14 awg Tefzel). When you get the same protection with penetrox coated copper wire for a fraction of the cost. How far can you get with a rewiring project with a cost basis of $1 to $1.50 per foot of #14 wire?

Dana has been almost totally rewired in the last 35 years without tinned wire and has never had a problem with wire corrosion. I am now in the process of rewiring my Son's Catalina 36. With the ends of the wire protected with Penetrox, the wires will never give him an issue. The cost of that protection, $2, maybe. The cost of adding the process of coating the wires with the Penetrox, $0, (maybe some time).

Mark, Glad to hear you are enjoying your cruise. In 1971 We were off Vieques Island killing sheep with 5" rounds from the guns of a US Navy Destroyer. Hope your visit is more friendly.

Jim
 
So, I had to look up the price of wire from my supplier because I didn't recall tinned wire being very expensive. #14 tinned marine wire is 0.32 per foot.

Yeah, it's going to be a bit more than $2 for dielectric grease (which you still need), but the cost difference is minimal, especially if you are not rewiring the whole boat all at once. For any given small project, it may only be $2-$5 more.

Primary Marine Wire - Stranded Tinned Wire | Pacer Group

Pacer marine wire is Type III Class K tinned copper & is built for flexibility & durability in harsh conditions. Trusted by top manufacturers and repair shops.
www.pacergroup.net www.pacergroup.net
 
Terry
If you have the black creep on your wire, your seeing the beginning of the problem. The wire will most likely carry the current but the corrosion will eventually increase the resistance in the wire causing more current to flow and maybe get to the point that the overcurrent device, CB or fuse, will trip or blow. My point is that you don't need, or are required, to use the fancy expensive wire to do the job properly. You only need to do the wiring job in a good workman like manner to prevent the corrosion from beginning. Using the dielectric grease on the connections adds a bit of time to each terminal but it does the same job as the tinned wire if done properly.

Jim
 
Thanks. In all my own wiring, I have used tinned wire and shrink wrap tubing. But there remain some original wires. I may try to start swapping them out. Thanks.
 
Terry
As for as I know on Dana, the only original wiring remaining is part of the cabin lighting wires up under the headliner. Those wires are probably well covered with creep but are still working. I couldn't begin to guess on the miles of wire, of all different sizes, that have gone into her rewiring. Enclosed are a few photos of the rewiring I am doing on my Sons Catalina 36 this winter. Using mostly non-tinned wire, but insuring that all the wire ends are well coated with Penetrox. Hopefully this will last another 40 years.

Jim
 

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jimcleary said:
Terry
As for as I know on Dana, the only original wiring remaining is part of the cabin lighting wires up under the headliner. Those wires are probably well covered with creep but are still working. I couldn't begin to guess on the miles of wire, of all different sizes, that have gone into her rewiring. Enclosed are a few photos of the rewiring I am doing on my Sons Catalina 36 this winter. Using mostly non-tinned wire, but insuring that all the wire ends are well coated with Penetrox. Hopefully this will last another 40 years.

Jim
Click to expand...
Very nice!
 
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