Hand Wire Splicing

A long time ago I learned a method of splicing wire that has stuck with me since those early days.  I actually picked this method up while I was in the military (USMC) so I can't take credit for inventing it or perfecting it.  Almost all the connections and splices I make for electrical circuits are done this very same way.

First off, what's so important about the way you splice two pieces of wire together?  It’s quite simple, current, resistance and voltage (Ohms Law). The more resistance you add to a circuit the more you are blocking the current flow.   Referring to a splice or connection in a given circuit, current flow would like nothing better than a low amount of resistance and lots of wire to travel on. 

The resistance from a weak connection or poor connection can produce a tremendous amount of centralized heat. This heat can build the longer the current is flowing which also increases the resistance even more.  If you’ve seen a connector where the plastic housing has melted around the metal connector you’re witnessing resistance in an electrical circuit. 

To make this a bit clearer I like to use water as a comparison to voltage.  Water itself has no potential until you give it a push usually under some sort of mechanical or natural (gravity) pressure.  A dam is a good way to think of voltage stored in a battery.  (Lots of potential energy but is held in check by the resistance the dam puts against it.)  When the spill way is opened there is less resistance to the flow and the water (voltage) can now move through.  The higher the flow out of the dam (current) the more damage the water can do. 

Another way to explain voltage, current, and resistance is with a garden hose.  The hose acts like the wire in an electrical circuit.  The water pressure represents the current flow.  If you have a small nozzle at the end it can be compared to the resistance in an electrical circuit.  But, that's where the similarities end. 

Unlike water, electricity does not flow “in” the wire it actually travels “on” the surface of the wire.  This is one of the many reasons why there are so many small strands in a given wire.  A butt connector is one surface area, the surface area of the strands in a wire are not entirely used.  The strands in the middle of the wire are trapped between the other strands and have no chance to pass their electrical effort.  This forces the current to travel only through those strands that are actually touching the surface of the butt connector. Less wire strands being used means more heat buildup. (Ever seen a yellow butt connector turn brown?)

Using this hand splice method will allow a great deal more strands from each wire section to be touching the spliced area as possible.  With a little practice hand splicing will become a regular part of your electrical repair procedures. 

Here's my method of making a hand splice.

Items you'll need
Wire strippers 
Small gauge solder (60/40 is the best) I prefer a .031 size myself
Solder gun
Shrink tubing
Heat gun

For this example I'll use a 16 gauge wire.  It's a common automotive size and easy to work with.

First thing to do is strip back about ¾ of an inch of insulation from both wires that
you're going to be splicing.  Add a section of shrink tubing onto the wire. (Don’t forget
this step… or you’ll regret it after you’ve finished the splice.)   You should only need
about a 1 ½ piece of shrink tubing.

Divide the bare strands into two equal sections and form them into a “Y”
Hold a wire in each hand, now take the “Y” and interlock the two wires together. 
But, (very important) leave room between the two “Y”'s large enough for the outer
insulation from the “none” strip section of wire to easily pass through.  (For 16 gauge
wire the distance from insulation to insulation is about ¾ of an inch.)

Lay the “Y” sections down along the wire without bending them backwards, straight
and even with the wire. 

Find the edge of the gap you left in the “Y”'s (That thickness measurement of the
outside insulation, just about halfway between the two wires).  Using one hand pinch
down on that spot while taking the legs of the “Y” from the same side and stand them
straight up 90 degrees from the splice.  Now use your other hand with firm finger
pressure rotate the two legs of the “Y” around the splice towards the opposite wire. 
If done correctly the spacing you left between the two “Y”s will actually lie down
and end up right where the insulation begins.  Also, as you pinch and roll the bare wire
keep it snug as possible.  You want to end up with it no larger than the outside
diameter of the insulated sections.

Now switch procedures from the right hand to the left hand and stand the other
set of “Y” legs 90 degrees and do the same crimp and turn all the way to the other
insulated section of wire. 

Once you've got the hang of it you'll find that the splice is extremely strong even
without solder or shrink tubing.  Mind you, the first thing in every splice job is to
make a good mechanical fit.

When soldering be sure not to soak the splice with solder.  The solder is only to
aide in holding the splice in place so it won't unravel.  Obviously the shrink tubing is
for overall weather protection, and to shield the bare wire.

I guarantee the first couple of times you do this you'll find that you either have
forgotten to put the shrink tubing on first or that your splice is too sloppy and it
pulls apart without much effort.  Done right, the splice should have plenty of
mechanical hold. 

A lot of times I'll show this method to someone and not solder the splice at all. 
I'll just heat shrink the tubing down and hand it to them and tell them to pull
it apart.  (The surprised look on their faces when they can't pull it apart without
a whole lot of effort is priceless.)

The larger the gauges of wire such as 10 gauge or so, you'll have to use a
smooth jawed pair of pliers to help squeeze the wire down to make a good
tight fit.  I don’t recommend this for battery cable (4 gauge and larger).
Crimp or soldered connectors are still the best method for them. But for
the average gauge wire, 22, 18, 14, 16 etc... This method works extremely well.

Give it a try, and when you've mastered the technique try it on your friends and see how much effort it takes them to pull it apart, even without soldering it.

Good luck, and happy splicing!

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