Marine wire, what's so special about it???

[fishrdan]

I rebuilding a 01 boat and notice that all of the OEM wiring is not tinned wire, including the Mercruiser engine harness. Purchased a new surplus switch/breaker panel and again none of the wiring is tinned, but is marked as marine wire. My old 73 SeaSwirl, same thing no tinned wire.

I thought tinning the wire was one of the most important aspects of marine wire It does look like the wire has finer strands so it's more flexible, but to me it looks just like wire I have used for automotive applications.

I'm most likely going to buy tinned marine wire for my work, but was wonder why all marine wire is not tinned and why manufacturers don't use tinned wire...

Freshwater VS saltwater applications?

 

[SKEETR]

Re: Marine wire, what's so special about it???

Marine wire does not have to be tinned but it does work better in the long run if it is. Automotive applications do have a less fine thread to the wire. I'm sure the oem wire in a saltwater boat is all tinned or a manufacturer like boston whaler.

 

[drewpster]

Re: Marine wire, what's so special about it???

From my experience the best way to look at it is that you get what you pay for. Manufacturers must consider many things when developing and producing what they sell. "Do you have to use marine tinned wire to wire a boat?" The short answer is no. The truth is that automotive wire will work, but you get what you pay for. There is definitely a difference in quality in anything you buy, wire included. High quality marine grade wire is developed to perform in marine conditions. Automotive wire is designed to perform in automotive conditions. Each type has different levels of quality. There is such a thing as cheap unreliable wire.
You can bet that the manufacturers looked into the quality of the wire they used to build their product. You should to. My larger boat was wired using all marine grade wire. The system is about five years old now and works well. My smaller runabout was wired using good quality automotive wire. I took my time and did the best job I know how to do on both boats. The runabout had been stored unused in my shop for two years. (sad, I know) Before cold weather set in, my father, brother and I went on a three day camp trip to Carters Lake. I worked for several days prior to the trip getting the boat ready because of electrical problems. One included a bad connection at a ground for the CD ignition on the engine causing it not to run. Next time I will use Marine grade wire.

 

[tashasdaddy]

Re: Marine wire, what's so special about it???

freah water use, automotive wire will last longer than you are going to own the boat. salt water environment, it is questionable.

 

[Chris1956]

Re: Marine wire, what's so special about it???

Dan, The wiring harness on my '77 Merc was tinned marine grade. The wiring harness on my '93 Merc was non-tinned. I do not know if it is marine grade at all. Obvoiusly somewhere between '77 and '93, Merc changed their mind and saved some $$ on the wiring harnesses.

The real advantage of tinned wire is that even after decades of salt water use, you can still solder tinned wire, without cleaning the individual strands.

 

[V8BoatBuilder]

Re: Marine wire, what's so special about it???

Tinned wire is important where there is a chance that the connector will be exposed to moisture, even atmospheric moisture from fog. It costs more, so many manufacturers go without.

Non-Tinned wire can corrode quite easily at the crimp connector, because unless the crimp is sealed with heat shrink tubing, it's open to the atmosphere. This will happen over time (sometimes it takes decades). You might never have a problem if the wiring is kept 100% dry, but how often does that happen on a vessel?

Bottom line, you'll most likely be fine unless it's an open boat. But keep an eye on it if it will be carrying large amounts of current, and put circuit protection between the panel and the battery.

 

[drewpster]

Re: Marine wire, what's so special about it???

I have to put things in perspective to be fair. The little boat was wired end to end in 2000. My brother owned it for awhile between 04-06 where it was stored outside under a cover. I bought it back from him in 06 and it was used maybe twice until we used it in Sept. this year. It is stored in my shop.
The trailer was also wired with automotive wire in 2000. It has never so much as blown a bulb but the 4 pin connector shows some corrosion. The lights work great on the trailer.
So the system did not show signs of a problem until this year. That's 8 years! I used good quality automotive primary wire (12 ga.- 6ga.) to wire the whole boat. I cannot remember the brand name. I bought it from our supplier at work. So I agree with TD auto wire can work for fresh water on a trailered boat. But the wire I used is good quality. Not the junk you get from Pepautozone.
BTW- I used the proper connectors, the proper crimp, heat shrink w/glue liner, and solder on all connections.

 

[scipper77]

Re: Marine wire, what's so special about it???

Someone please correct me if this is wrong but it was once explained to me that by tinning wire you fill in the little voids in the wire thus preventing the ability of water to wick into the jacket. It was further explained to me that non tinned wire has a tendency to corrode under the jacket where the corrosion is not visible.

Sometimes the only indication that a wire is corroding internally is that as the conductive path gets thinner the wire will run hotter.

 

[Chris1956]

Re: Marine wire, what's so special about it???

Tinned wire does corrode less than non-tinned wire. However, we are still talking about solid copper strands, which need salt to really corrode. So if you have non-tinned copper wire, in a fresh water environment, it will be fine for a long time. If you are in salt water area, tinned marine wire is necessary to keep the wiring intact for many years.

When I bought my new motor, I butt spliced the new harness to the old harness. I have been too lazy to redo the job properly, and one day I will pay the price for this. Maybe next spring, I will have the motivation!