Why butt connections are not a good idea in an exposed environment.

[Bigsfish]

Since I discovered Anchor connectors that come with a sealant and shrinks down with heat about 20 plus years ago I’ve never had a problem. Probably just lucky but I continue to use them.

 

[DarrenCharles]

Some interesting comments on a face value simple topic, which may not be quite so simple. I have learned I will not be using wire nuts, no matter how careful I am.

I did some YouTubing and found this comprehensive video about wire connections. It suggests not to tin because ridges may be created that affect the crimping connection. The video was not marine specific, so the corrosion protection of tinning may trump the non perfect surface area of the tinning.

Good video if you fast forward as needed. Here is the link. https://youtu.be/kjSGCSwNuAg

 

[JDCAVE]

You say, "for the engine", what exactly is is for?

It’s the battery cable for the outboard. The P.O. used a combination of this brand of cable called “Seiwa” from the outboard to the battery. I believe both wires were tinned, although I didn’t inspect the Seiwa cable carefully and the electrician took it away with him.

The butt connection definitely failed and I believe the heat shrink was the one with adhesive but I’m not certain.

Jim

 

[Frosty]

It suggests not to tin because ridges may be created that affect the crimping connection. The video was not marine specific, so the corrosion protection of tinning may trump the non perfect surface area of the tinning.

Pardon me if this elementary, but when you buy marine wire it is tinned. Meaning that each strand has a tin "coating" that is basically built in an smooth. OTOH, to "tin" wire is (AFAIK) to take the wire as a hole an melt solder into it. This makes it more rigid and I think this is what they are advising against.

So you DO want "factory" tinned wire (such as Ancor or others), but that's not the same as you "tinning" it.

 

[grahamdouglass]

After doing the crimping but before the heat shrink try using neverseaze, especially for battery connections. Overtime the neverseaze works it’s way up under the cable covering and keeps it protected.

 

[exmaggiedrum]

Butt splices

I've done many, many thousands of butt connectors, along with ring terminals, heavy duty lug connectors of all types. Also a member of ABYC but that seems to be a dirty word for some people. Here are some thoughts:


- Never, ever, ever use wire nuts on a boat. There is no way, at all, to isolated them from vibration and they will come loose. When they come loose the wires will not be connected tight and the resultant high resistance can cause overheating and, many time, a fire


- Unless you use closed end ring terminals they are just as susceptible to the marine air as a butt connector. Only a butt connector can be sealed with adhesive heat shrink. An open end ring terminal cannot be sealed on the one end so it is always open.


- Heat shrink is worse than no heat shrink if it is not done 100% correct - good quality, right size, not overheated, adhesive lined. The reason it is worse is now you have a butt connector that your cannot inspect to see if it is corroded. Make sure you use the right length of heat shrink so that it extends proportionately past each end. Saving money on short adhesive that looks like it seals well but doesn't is short sighted. Spend the money and get extra.



- Good quality terminals, for any purpose, should be high quality and not the junk I have found on a few boats from time to time. Trying to save money on cheap connectors is just ignorant (not that anyone would ever do that of course).


- The crimp has to be good. You can make a perfectly good crimp without certified crimpers. You can make bad crimps with certified crimpers. Always give any new crimp a good strong tug to make sure it is solid.



- Exception - heavy duty lug terminals should always be done with a professional tool that is sized for that particular terminal. There are different size diameters and configurations of lugs of the same size. They sell crimp tools specific for the brand and size of the lugs. When Fisheries changed brands of lugs on me, my $400 crimpers would not work with them.


- As noted, never make a crimp that will even occasionally be wet on a constant basis unless it is protected by a properly done heat shrink and preferably not even then. It is best to use a continuous wire and to put the terminal block in a dry location. Sometimes this isn't possible so you have to check the connectors routinely.



- Give a good tug to old butt splices once in a while if you have them disconnected from their holddowns.


- All wires should be secured per standards, but especially at any connector or terminal. As in as close as physically possible.



Sorry to be so pedantic. My hot button was to get on a boat and find really bad mistakes on there from bad connections. I have, literally, had to rewire engine rooms because of bad terminations leading to a fire. Twice. I have had to rewire whole electrical panels for the same reason. I had to replace the AC panel on my new (old) first boat that had burnt up behind the panel. The boat inspector did not find it as they don't open up anything requiring tools and the previous owner had spliced around the breakers that had melted. I was pissed!



Hope you all have as much fun on the water as you can with the virus now. A lot of things closed down in the San Juans right now and the season has just started.

 

[JP2]

FWIW: As was noted, the Irrigation industry has some experience with heat shrink tubes. Some years ago, one factory that manufactured precision moisture sensing equipment for very sophisticated control systems, did an extensive study on about 25 different brands of shrink tubes. Not one passed their test and prevented moisture entry. Of the brands tested, their preference for was 3M, if I recall correctly, in applications where a shrink tube was the only solution, or when installers simply insisted on using them.