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This article in Practical Sailor says that as long as your crimps are watertight you don't need to use tinned wire.

It also says:
the vast majority of production boat builders still use un-tinned wire in their electrical systems
Is this true, do boats come from the factory with automotive wire?

What do you all use?


Tinned Wire Myth Busted
 

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Dirt Free
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This article in Practical Sailor says that as long as your crimps are watertight you don't need to use tinned wire.

It also says:


Is this true, do boats come from the factory with automotive wire?

What do you all use?


Tinned Wire Myth Busted
every wire is exposed at the end. Ring terminal, spade connector etc. Corrosion can (will) creep up the conductor from there. How important is corrosion resistance to you. Me ..... i'll happily pay the extra for tinned and do the job only once.
 

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This article in Practical Sailor says that as long as your crimps are watertight you don't need to use tinned wire.

It also says:


Is this true, do boats come from the factory with automotive wire?

What do you all use?


Tinned Wire Myth Busted
a. The crimps won't fail if they are tight. That was the real point. Tin won't help if they aren't. Use ratchet crimpers and adjust them to the wire. However, if you try to repair the wiring, you may find corrosion up under the insulation unless it was very well sealed.
b. USCG does not require tinned wire. ABYC does, but it is a voluntary standard.
c. Your should REALLY try to keep wiring away from moisture, particualry salt water. Even tin won't help if the exposure is chronic.
d. The source article and testing referred to THHN wire only, which is more coarse stranded than SAE automotive wire. This makes a difference. Non-tinned SAE wire, required on high vibration applications, like engines, does not hold up very well.
e. It depends on where in the boat we are talking. In the bilge or to exterior lighting, tinned wire is a bargain. But if the area around your main panel and in the cabin is so damp that there is a difference, you have problems. A lot of things will fail. Yes, many of the appliances in a boat are pretty much household inside. The AC unit or heater, for example, will use all non-tinned wire internally and non-waterproof components. Except for bilge pumps, this is quite common.

The smart answer is to use tinned wire, but don't buy it at the chandlery:wink. They kill you. Buy a full spools of several colors and gauges on-line and figure it will last for years. And buy name brand tinned crimp fittings.
 

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every wire is exposed at the end. Ring terminal, spade connector etc. Corrosion can (will) creep up the conductor from there. How important is corrosion resistance to you. Me ..... i'll happily pay the extra for tinned and do the job only once.
And the problem isn't just the wire! It looks like a lot of plain steel parts. The screws need to be stainless and the terminal strips and buss bars should be tinned copper, even if the wire is not tinned. It's more critical.

The other thing that helps is a smear of waterproof grease. Keeps the water out.
 

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I agree to some extent that tinned wire is not necessary. Pretty much all European and South Africa boats use untinned wire.

We presently own two boats - one with tinned wire since build in 1998, and the other with untinned wire since build in 2005.

The 1998 boat has no wire corrosion or connection issues at all. Surprisingly, it also has almost no heat shrink terminals or covering on any of it. Even butt joins. When I do need to remove and reinstall a terminal or butt connector for whatever reason, the wire has always been in good shape. At worst, in the wet anchor or deck locker, I have had to cut back an inch or two to get good wire.

The 2005 boat has a lot of corrosion at connectors. Even the sealed ones. It doesn't take much to breach a sealed connection, and end connectors (ring terminals, etc) are almost impossible to seal fully. I am changing a lot of the terminals and wiring for other reasons, and in the driest places, when I remove a terminal the ends have a lot of black on them. Probably 50% of the strands are black. I usually need to cut the wire back several inches to find non-black strands, or at least only 20% black strands. In the wet areas, like the anchor and deck lockers, things are much worse. I have had to cut feet off wires to find shiny wire. In fact, I am rewiring all of these wetter areas just because I'm finding so much wire corrosion. Most of these have heat shrink terminals and tubing on them.

Having said all of that, I still don't think tinned wire is the end-all and be-all of boat wire, and that good untinned marine wire is fine. I would probably always use tinned in wet areas, but then none of the bilge pumps, switches, shower sumps, holding tank pumps, etc that I buy have tinned wire on them. So using tinned wire on these is not helping anything.

In the US, there really isn't many choices for suitable marine untinned wire. I think that is why it gets such a bad rap - people are using unsuitable or cheap wire and not differentiating between applications. I suspect the costs are similar for good untinned wire and tinned wire.

Mark
 

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This article in Practical Sailor says that as long as your crimps are watertight you don't need to use tinned wire.

It also says:


Is this true, do boats come from the factory with automotive wire?

What do you all use?


Tinned Wire Myth Busted
I don't worry about tinned wire and fee the connection is more important.

I my mind wires cars in the NE and other snow areas see a lot more corrosion conditions than the inside of my boat.
 

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I respect boatpoker's opinion on these matters and I'm staying out of the debate. However, in this case, I think his photos are very misleading; those awful connections would not be any better if tinned wire had been used.
 

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Don't think it is necessary. I have a 35 year old boat and none of the original wire is tinned. I've replaced a lot of the lights, pumps and other boat bits and only found one wire that showed corrosion. That being said, when I add new wire I always use tinned wire.... well almost always.
 

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I respect boatpoker's opinion on these matters and I'm staying out of the debate. However, in this case, I think his photos are very misleading; those awful connections would not be any better if tinned wire had been used.
The point I was trying to make was that corrosion creeps. It will creep and do more damage to non-tinned than tinned.
 

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I don't see anything in those pictures that has anything to do with the wire itself, and no sign of wire corrosion - or even what type of wire is being used. They really don't have anything to do with the tin/non tin discussion.

Mark
Wow, I thought my point was simple and clear. I guess not.
You win.
 

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When I rewired my old boat a 74 Ericson. I found so much corrosion in the old wires. So when i did the rewire I did everything up the highest standard I could, knowing the wiring would outlive the boat. It seems the real cost of a rewiring job is in the labor whether you are paying someone to do it or not paying yourself to do it. Why take any shortcuts?
 

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... In the US, there really isn't many choices for suitable marine untinned wire. I think that is why it gets such a bad rap - people are using unsuitable or cheap wire and not differentiating between applications. I suspect the costs are similar for good untinned wire and tinned wire.

Mark
Stranded THHN wire is the most common industrial wire in the US and is stocked by Home Depot, Lowes, and every electrical supply house. It is what is pulled through conduit. People may not know to look for it.

https://www.homedepot.com/p/Southwire-500-ft-12-White-Stranded-CU-THHN-Wire-22965858/203401697
 

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Stranded THHN wire is the most common industrial wire in the US and is stocked by Home Depot, Lowes, and every electrical supply house. It is what is pulled through conduit. People may not know to look for it.

https://www.homedepot.com/p/Southwire-500-ft-12-White-Stranded-CU-THHN-Wire-22965858/203401697
ABYC standards cover much more than what has been discussed here, wire type, strand size, oil resistance of the insulation, temperature rating and voltage loss among others. I don't know if Home Depot conductors would meet those requirements.

Of course many have no use for ABYC Standards. To each his own.
 

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The cover of wire is osmotic. If you pass the wire from the bilge, water will osmotically pass to the wire and cause crevice corrosion. It is best to use tinned wire.
 

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Stranded THHN wire is the most common industrial wire in the US and is stocked by Home Depot, Lowes, and every electrical supply house. It is what is pulled through conduit. People may not know to look for it.

https://www.homedepot.com/p/Southwire-500-ft-12-White-Stranded-CU-THHN-Wire-22965858/203401697
Here is HD's price for 100' of THHN - $28.37: https://www.homedepot.com/p/Southwire-100-ft-12-White-Stranded-CU-THHN-Wire-22965884/204868304

Here is 100' of tinned marine wire - $27.50: 12 AWG Primary Wire Marine Grade Tinned Copper Black 100 ft

Going with untinned wire in the US is not for cost reasons. Outside the US, it most likely is. I suspect anyone using untinned wire in the US, and having problems with it, is using cheaper stuff than THHN.

Mark
 

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The cover of wire is osmotic. If you pass the wire from the bilge, water will osmotically pass to the wire and cause crevice corrosion. It is best to use tinned wire.
I'm pretty sure this is not true. At least not on less than glacial time scales. Likely, any issue with water will be one of wicking from a penetration, and not osmosis. Could you point to a reference regarding this? If osmosis and crevice corrosion is a concern with marine wire, tinned wire won't prevent it.

Mark
 
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