Tinned & Untinned Wire (Again).

[Wotname]

Originally Posted by Thumbs Up

My boat was built in S. Africa in '97. Wired with #12 untinned wire. The strands are all black no matter where I cut them. I measured a pretty big voltage drop on some high amperage circuits. Switching to led lighting helped a lot. I wonder if there is a major quality difference between brands of untinned stranded wire. What about quality difference between brands of tinned? Could a good quality untinned wire be almost as good as a crappy quality tinned? What about the number of strands a wire has. Does anybody have any real experience trying solid wire? I know this is not recommended due to vibration issues but many boats suffer very little vibration. It seems like solid core wire wouldn't suffer at all from corrosion. I wouldn't try it in the mast, or for engine wiring but what about cabin wiring where all of the runs are well supported and non movable?

Within reason I don't think there is much difference in the copper used between different wire makers and I very much doubt if anyone would attempt to tinned low grade copper - but I could be wrong
There is considerable difference in the quality of insulation between various grades of cabling.

[Cheechako]

While I wouldnt panic if I had a boat with untinned wire, I am a proponant of tinned wire for sure. I have pulled out untinned wire and tried to strip back to get clean copper inside the plastic jacket... but found that the wire is oxidized for even a few feet from the end. Realistically... i'm not sure this has a bad effect though. (although I've been told that electricity flows on the surface of wire.... is this true?) If the jacket is gouged, untinned wire can corrode through pretty readily. Also I've seen many wire ends corrode and break off right at the fitting... and these may not have done that with tinned wire. So as you say... it's more forgiving for someone who doesnt do the install right in the first place.. I've had several older Taiwanese boats all without tinned wire... really havent had many electrical problems with the wire though....

[Wotname]

Originally Posted by Cheechako

....... although I've been told that electricity flows on the surface of wire.... is this true?....

Partly true. For DC (and low frequency AC) it doesn't matter. It certainly matters for high frequency AC and once you get into RF it becomes critical. I forget the actual numbers but others here who are smarter than me may remember.

Edit: google found this for me http://daycounter.com/Calculators/Sk...lculator.phtml
and this
http://en.wikipedia.org/wiki/Skin_effect

[Target9000]

It also seems the cost of upgrading to tinned wire is low enough that it really is a trifling compared to the cost of labor.

I just did some quick checking online and I can find 500ft duplex 12 awg cable:
non-tinned: $285
tinned: $320

Is the 40 bucks going to break anybody? I mean unless you're doing thousands of feet of the stuff it really isn't all that big a deal.

[David M]

Originally Posted by RabidRabbit

Crimping works but why not solder the connections. It will make any untinned connection last longer and it makes a tinned joint total pro. Do others make this a habit?

A solder joint can come undone if the wire gets hot enough. Or an onboard fire could undo your connections. Then you have a possibly loose hot that could cause other problems. Or you could have a bunch of loose wires that could accelerate the fire or create high voltage in areas where you are not expecting there to be high voltage.

The USCG (under the CFR's) does not allow soldered electrical connections on inspected passenger vessels for those reasons. The connections must be mechanical (crimped or otherwise mechanical).

I don't know what ABYC says, which sometimes has standards lower than what are found in the CFR's.

A lot of recreational boaters do solder only connections because of the electrically reliable, low resistance connection.

[Wotname]

Originally Posted by Target9000

It also seems the cost of upgrading to tinned wire is low enough that it really is a trifling compared to the cost of labor.

I just did some quick checking online and I can find 500ft duplex 12 awg cable:
non-tinned: $285
tinned: $320

Is the 40 bucks going to break anybody? I mean unless you're doing thousands of feet of the stuff it really isn't all that big a deal.

Shh...don't tell the europeans, apparently they love their untinned wire!

[CeesH]

Originally Posted by goboatingnow

Never solder and crimp. If you want solder terminals use proper ones. A good crimp,never needs solder , then slider work happens the joint a d under vibration. Fails. Not to mention few people solder well ( they think they do) and this creates high resistance joints. You'll never see a crimp and solder joint in a car harness, which is subject to far more vibration.

Dave

Its not the vibration that lets the joint fail, its called "cold flow". Under pressure solder starts to flow and loosen the joint. So or crimp or solder.. never crimp soldered wire.

CeesH

[Cheechako]

Originally Posted by Target9000

It also seems the cost of upgrading to tinned wire is low enough that it really is a trifling compared to the cost of labor.

I just did some quick checking online and I can find 500ft duplex 12 awg cable:
non-tinned: $285
tinned: $320

Is the 40 bucks going to break anybody? I mean unless you're doing thousands of feet of the stuff it really isn't all that big a deal.

Strand count matters, so watch for that when you buy.... I've seen stranded wire that has very few strands in it and is pretty stiff. Apparantly the more strands the better the flow of electricity....

[David M]

More strands allows for tighter bends by lowering the chance of individual strands breaking. More strands also allows for more secure mechanical connections.

The sum of the cross sectional area of the individual strands has everything to do with the wires ability to carry current and not necessarily the number of individual strands.

For boats that have mechanical connectors and sharp turns, the more strands you have for a given gauge, the better.

[btrayfors]

This debate has been carried on ad-nauseum here and elsewhere.

The reason not to solder has more to do with taking flexible multi-strand wire, tinned or other, and effectively making it into solid wire. That's a no-no on a boat because of potential flexing, cracking, and breaking. This is in addition to other problems noted above.

For heavens sake, the cost of the wiring itself is a small part of the REAL costs of wiring or rewiring a boat, particularly if it's done correctly. Good wiring takes tons of time.

Why in the world would anyone use clearly inferior non-tinned wire on a boat or an airplane, when the difference in cost for high-quality tinned wire is relatively small?

Anyone who knowingly does so, IMHO, is either a skinflint practicing false economics or doesn't place any value on his/her time.

And, based on my experience with electrical systems on EU boats, particularly French boats, I certainly wouldn't hold these up as good examples of boat wiring.

The French excel in lots of ways on the water, but IMHO are often somewhat "challenged" in the electrical department.

Bill

[David M]

Agreed. Don't cheap out on your wire if you value your time and want a reliable electrical system.

[bobconnie]

Now you guys have me "cornfused" Ive been soldering my wires after hand crimping them for more years then even I want to remember!! Never had one vibrate, or become loose from heat yet !! I use heat srink wrap now! but for years before it was available I used rubber wrap and tape. Ive never had a problem from either type of finished joint. I now use only tinned wire, but there was a time, that some of you older folks may remember when there was just WIRE !! I wired our home bilt Colvin with un-tinned wire and solderd joints and rubber and taped joints and we sailed her 20 + years with no problems with the wiring!! but I did have some problems with a yard installed crimped wireing on a SSB radio. so I guess Im gonna keep useing TINNED wire and solderd connections, till someone shows me real crimped joint that lasts 20 + years of real cruising 50,000 + miles under sail and engine! just my 2 cents

[Target9000]

Originally Posted by Wotname

Shh...don't tell the europeans, apparently they love their untinned wire!

Since its advice from a yank, its got to be bad right? Don't sweat it; they'll never listen.

[minaret]

Originally Posted by Target9000

Since its advice from a yank, its got to be bad right? Don't sweat it; they'll never listen.

I do find it highly entertaining how none of the dissenters from that other thread are chiming in here. To busy spending 500k on a brand new boat with untinned wiring I guess.

[four winds]

I think that might have been in the multihull forum. I'm not sure they get out of there much to look around the rest of CF.

For me, taught by the Air Force, it's crimp, solder and shrink.

My 33 year old boat has original tinned wiring with no issues. And newer wiring from equipment upgrades with untinned wire that is in sad shape. Spent some time a couple of weeks ago fixing things.

I found corrosion throughout this wiring, and I trimmed, scraped and redid several connections with the intention of replacement later.

I was taught flow is on the surface of the strand because that is where the covalent electrons have the easiest time jumping from one atom to the other. And that more strands creates more surface area, reducing resistance.

A run of corroded wire is a long resistor in my opinion. Considering that a resistor is just a calibrated bit of corrosion in a capsule makes me think this.

With untinned wire, when I tin the end after crimping, first, the last bit of the run is shaped for the installation position. Then the tinning is wicked well up into the insulation with non corrosive flux. This is solid and does not flex as happens when only the very tip end is tinnned and untinned strands are visible at the cut on the insulation. That creates a flex point that will cause failure.