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ContinuousWave: Small Boat Electrical
Connecting Small Gauge Wire Conductors
|Author||Topic: Connecting Small Gauge Wire Conductors|
posted 09-16-2012 01:00 AM ET (US)
I have a ControlKing unit attached to my Yamaha T8 kicker. This is an electrical control unit that is used to control the throttle on the kicker from the console. There is a plug on the unit that joins three wires from the control on the console to three wires on the servo motor that is on the motor. The plug has corroded and the connection is now broken. As a quick fix I have stripped the wire that no longer has a connection (due to the corrosion) on each side of the harness and alligator clipped them together.
These wires are very small wire gauge. What is the proper device to join toether two wires over very small wire gauge? I'd like to cut the plug out, strip all three wires and connect them permanently with something.
posted 09-16-2012 08:43 AM ET (US)
Solder them and cover the exposed wire with shrink-wrap tubing.
posted 09-16-2012 08:58 AM ET (US)
See also a previous discussion on this topic at http://continuouswave.com/ubb/Forum6/HTML/002892.html .
posted 09-16-2012 09:56 AM ET (US)
What is the approximate wire gauge of the conductors you wish to join?
On a boat the minimum wire gauge used for any circuit should be 16-AWG, unless the wiring is internal to an assembly.
To connect wires of 18 to 22-AWG you can typically use a butt splice with red color-coded insulation.
If the conductors are solid conductors, you can use the very popular and very well proven (by decades and decades of use) SCOTCH UY connector. See
If the conductors are stranded conductors, I recommend you twist them together, solder them without letting the solder wick back into the wire, and cover with insulation. For insulation you can use heat-shrink tubing.
posted 09-16-2012 10:10 AM ET (US)
Ditto on the Scotch connectors, especially the model that has a small bit of sealant inside them. Used them for years wiring up, uh.......devices in plain looking vehicles. 'Nuff said. Was turned on to them by an old Ma Bell tech, who gave me a hand full of 'em.
Regards - Don
posted 09-16-2012 12:08 PM ET (US)
ASIDE to Don: I have installed so many Scotch-Lok connectors that I even have the specialized tool for crimping them.
posted 09-16-2012 03:22 PM ET (US)
Since the size of the wire is supplied with the control unit, there's not much you can do about that. Carefully soldering the connectors together and protecting the joint with heat shrink tubing is your best bet. You can get the tubing that has an integral layer of hot melt glue, which provides better waterproofing of the joint. West Marine carries it. I found a short video that shows the basic technique.
posted 09-16-2012 03:57 PM ET (US)
Re the video (linked above):
--the soldering iron is huge, much to large for working with 22-AWG wires
--the heat gun is too hot; it could strip paint. Be very careful with a heat gun like that trying to work with small conductors in-situ on your gasoline outboard engine.
posted 09-16-2012 06:00 PM ET (US)
You need to go to an electronics store (some radio shack carry them) and get a good soldering iron for electronics and learn how to solder, Using the 3m connections that Jim has shown in his thread you will be asking for trouble, those connections are good for land use I would never use one on a boat, Trust me, learn to solder and use the heat shrink and then cover the connection with a grease substance or liquid tape...
posted 09-17-2012 09:10 AM ET (US)
The SCOTCH-LOK connectors will still be in fine shape 50-years after the little electronic gizmo stops working. They have a sealing mechanism and a gelled liquid inside that coats the electrical connection to prevent corrosion.
posted 10-04-2012 11:29 AM ET (US)
If those are the "Scotch-lock" connectors I remember using as a tech they were designed to be used with single strand inside-wire wire used by the telcos, not the multi-strand wire found in many consumer devices. Just my $.02.
posted 10-04-2012 12:00 PM ET (US)
jimh says in the earliest part of the discussion:
"If the conductors are solid conductors, you can use the very popular and very well proven (by decades and decades of use) SCOTCH UY connector."
Then, later, Glen says:
"If those are the "Scotch-lock" connectors I remember using as a tech they were designed to be used with single strand inside-wire wire used by the telcos, not the multi-strand wire found in many consumer devices."
Glenn--The SCOTCH UY connector is widely used with solid conductors of small wire gauge. See my comments about use of SCOTCH UY connectors from the earliest parts of the discussion that I reproduce above.
Although SCOTCH UY connectors were (possibly) designed for use solid conductors and have been quite successfully used with solid conductors for three decades in the field of telecom wiring, I would not rule them out for use on stranded conductors. I have used SCOTCH UY connectors on some stranded conductors. The insulation displacement method that is used in the SCOTCH UY connector has also been used in similar connectors in the telecom industry since the 1960's--about five decades of use--with stranded conductors, such as those found on the extremely common modular telephone cord that is in universal use in telecom wiring. To say that an insulation displacement connector can't be used with stranded wire is to make a rather broad statement, and I am not willing to make that statement.
posted 10-05-2012 10:27 AM ET (US)
Jim, I did read that, just lost in translation to my hard-drive. mea culpa!
posted 10-05-2012 01:19 PM ET (US)
Where can one purchase these Scotch connectors without buying in bulk?
posted 10-09-2012 11:00 AM ET (US)
The original wiring from Whaler on my boat had a few connectors that looked almost identical to those Scotch connectors...
posted 10-09-2012 11:15 AM ET (US)
To be clear, I don't recommend using Scotch-Lok connectors in any sort original equipment installation. I would use them to make a repair when in a hurry.
On a small boat the longest electrical conductor is probably going to be less than 20-feet long, and to make a splice in a conductor seems rather a bad practice. If a conductor is damaged, it should be replaced with a new conductor, one-piece, end-to-end for the circuit. I abhor splices.
posted 10-09-2012 11:32 AM ET (US)
I could see how those Scotch connectors might be a good option where you must splice small wires, such as the NMEA wires between a VHF radio and GPS for DSC.
posted 10-09-2012 11:28 PM ET (US)
The SCOTCH-LOK connectors are a one-time use connector. If making up an interface between serial data ports with NMEA, you better get it right the first time if you are going to use SCOTCH-LOK connectors.
For my solution to interfacing NMEA serial data devices, see
posted 10-10-2012 08:47 AM ET (US)
For NMEA connections the European-Style Terminal Strip works great. They give you a lot of flexibility not only in your present instal but also if in the future you add something new or replace something at your helm. You can purchase these at Radio Shack for $3.49.
I've used them on all my electronics install on my Whaler as well as client boats.
I also use them for connecting multiple speakers to a source output (in this instance a Simrad Sonic Hub)
They're also easy to use in tight to reach locations where NMEA connectivity is needed. Sorry for the quality of the photo.
There you go .......
posted 10-11-2012 02:30 PM ET (US)
The point of the video is to show the basic technique used for making the connection. While the soldering iron may not be ideal, it looks like it worked and an acceptable connection was made. In terms of the heat gun, they are all pretty much the same, and you can control the amount of heat applied by moving the gun closer or farther from the work as needed. I have used a similar heat gun to seal electrical connections with great success, and never damaged any part of my boat in the process.
Bottom line, if you are careful and use good technique, you can make a very satisfactory electrical connection with tools you probably already own, and without purchasing some type of exotic, industrial quality electrical connector that nobody outside of the electronics industry has ever heard of.
posted 10-12-2012 08:07 PM ET (US)
According to some advice i have seen given here in the past, you could connect two wires as follows:
--use the cap from a small tube of toothpaste, for example, those small tubes of toothpaste you carry on trips when you have to fly and can only carry small quantities of personal items; rinse the cap under hot water to remove all the toothpaste; let the cap try thoroughly. It will make a nice wire nut for small-gauge wires;
--twist the small gauge wires together and screw on the toothpaste cap as a wire nut;
--use boat sealant to fill any space or gaps in the toothpaste cap and seal the wires into place
There you go! An electrical connection without using any sort of specialized electrical component designed for the actual purpose. Now, do I endorse this method? Of course not. I would not use this method unless my boat were sinking and there were no other options. But it is a workable method for making a connection between two wires on a boat, and this has actually been suggested by others (although I don't know if they improvised the toothpaste cap in place of the wire nut--I had to use the toothpaste cap because I did not want to use any specialized electronic parts).
posted 02-18-2013 02:34 PM ET (US)
Update: I went ahead and tried the soldering technique illustrated in the video. My job is not as pretty but the connections were strong and the unit functioned fine. We'll see how it holds up.
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