How to do a Basic Wire Splice

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krazykuda

krazykuda

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krazykuda submitted a new Article:

How to do a Basic Wire Splice

Hi everyone! I'm here to show you how I splice electrical wires. One of my old bosses was an electrical engineer and he gave me some advice on how to properly splice electrical wires.

I've seen many attempts at splicing wires with my cars over the years, and I've seen some real hack jobs. I will walk you through how to splice two wires together for long term service and dependability. This will include soldering, as it is more permanent and will give you many miles of trouble free service when done right.

Of, the first thing that you have to do is to strip the ends off of the wire. I like to strip about 1" or a little more for my splices, and you will see why in a little bit in the next section.


I like my "auto stripper", but you can use the basic wire strippers if that's what you have:

View attachment 1715004174




Strip the insulation off of the wire:

View attachment 1715004175




After you strip the insulation off, it will be "frayed" and looks like this:

View attachment 1715004177




Now you twist the strands of the wire together and they should look like this:

View attachment 1715004178




Now we move on to the next section on how to connect them....

Now I will show you how my boss explained the proper way to splice.


First thing you do before you splice is to cut some shrink wrap (also called heat shrink tubing) and slide it down the wire away from your splice so the heat doesn't shrink it while you are soldering. Get it away from the heat until you are ready to shrink it on your splice. Make sure that you cut the shrink wrap so it covers all of the bare wire and a little of the insulation on each side of the splice.


View attachment 1715004189




Now, here I am going to show you the "not so good" way of splicing, that I don't recommend. This is where you "hook" them together like this:


View attachment 1715004190




Here it is twisted together like this:


View attachment 1715004191




Notice the red part showing how you only have "transfer contact" at the points where the two wires meet, and that's it:


View attachment 1715004192




Here is the way that my boss showed me how to do a splice, You put the two wire ends together side by side and twist them together along the length of the stripped wires:


View attachment 1715004193




Here is how you twist them together so they contact lengthwise along the whole length of the stripped wire:


View attachment 1715004194




Now here is the red line showing how you get more contact along the length of the splice, instead of just point contact as shown above. This way gives you more surface area for your splice and for the current to flow:


View attachment 1715004195

Now you need to put flux on the wires for the soldering. I like the paste flux as shown, you may also use the liquid, whichever you prefer to use.


Here is the paste type flux and a flux brush:


View attachment 1715004198




Now put some flux along all of the exposed/stripped wire:


View attachment 1715004200




When done, it should look like this:


View attachment 1715004201

First you need to heat up the soldering iron and get it nice and hot. I like to use a Weller 40 amp soldering iron available at most home improvement/hardware stores. If you are soldering a bunch wires together, you may want to get a higher wattage iron. For this example, I will just splice just two wires together to keep it simple.


One thing that you will need is a wet sponge. Get an old sponge and cut a bit of it off and get it well soaked in water, but not so much that it drips. Just enough so it doesn't drip.


Now heat up the iron, and the tip may look cruddy/crappy when it gets fully heated like this:


View attachment 1715004204




Now you need to clean the tip. To do this, just swipe it along the wet sponge until it looks clean and shiny like this. Don't worry, the sponge will not burn or catch fire when it is soaked with water:


View attachment 1715004205




Here's what the clean tip should look like:


View attachment 1715004206




Now you need to "tin" the tip. This is where you melt a bit of solder on the tip of the iron. Be sure to do both sides.


View attachment 1715004207




Here is a nice clean and tinned tip.


View attachment 1715004208




Now you are ready to move on to soldering....

Now we are ready to solder the wires together. I like to hold the soldering iron under the wire to heat up the wire first. You can hear the flux "boiling" while you do this. Then after the wires get good and hot, touch the solder to the wire (not the iron) and let it flow along the whole length of the splice. This will get the best bonding for the solder to the wires.


Here I am holding the soldering iron under the wires to heat them up:


View attachment 1715004213




Once the wires are hot and the flux has melted, touch the solder to the wires like this until the solder is completely covering all of the wires:


View attachment 1715004214




Here is what it should look like when you are finished:


View attachment 1715004215

Now you need to insulate the solder joint so it doesn't short out. Slide the heat shrink tube over the joint after it has time to cool. Make sure that it covers the whole length of the splice and overlaps the insulation on each side of the joint. You can use more than one layer of heat shrink if you wish. The better it's insulated, the less chance for it to rub through from vibration while you drive.

I like to use a lighter to shrink the tubing, you can also use a heat gun.


View attachment 1715004216




Go back and forth along the length of the heat shrink tubing until it is nice and snug.


View attachment 1715004217




Here's what it should look like when finished.


View attachment 1715004218

Even with heat shrink tubing, I still like to cover it with electrical tape for extra piece of mind. I like to cover it with at least 3 layers or more of tape.

Here's me starting to tape the wire. Make sure that you completely cover all of the shrink wrap and a little extra on each end.


View attachment 1715004223




Here it is with three or four layers of tape over the heat shrink. This puppy should be well insulated and not ground out by now.


View attachment 1715004224




Here is a bundle of wires that I have spliced on my son's car. After you get all of the wires spliced, then I like to wrap them up like the factory. I use a few pieces of tape along the wires to keep them together while I run tape along the full length of the wires.


View attachment 1715004225




Here is the bundle all taped up:


View attachment 1715004226




In case you are curious about what we are working on, it's my oldest son's 72 Challenger Ralley. It's an original triple black car - black paint, black vinyl top, and black interior, 318 car with R/T hood, console, buckets, and ralley dash. The engine is the original 318, freshly rebuilt and we put 360 heads with 2.02" intake valves. My brother bought it from someone that we knew back in high school that was the second owner. He drove it a while, and then sold it to me. Then I drove it for a while, then sold it back to my brother. He has now handed it down to my son. It has just under 100 k miles on it.


View attachment 1715004227




Now you know how to properly splice electrical wiring. Good luck with your projects. I hope that this will help you if you need to splice any wires.
Click to expand...

Read more about this article here...
 
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krazykuda said:
Even with heat shrink tubing, I still like to cover it with electrical tape for extra piece of mind. I like to cover it with at least 3 layers or more of tape.

Here's me starting to tape the wire. Make sure that you completely cover all of the shrink wrap and a little extra on each end.

View attachment 1714749030

Here it is with three or four layers of tape over the heat shrink. This puppy should be well insulated and not ground out by now.

View attachment 1714749031

Here is a bundle of wires that I have spliced on my son's car. After you get all of the wires spliced, then I like to wrap them up like the factory. I use a few pieces of tape along the wires to keep them together while I run tape along the full length of the wires.

View attachment 1714749032

Here is the bundle all taped up:

View attachment 1714749033

In case you are curious about what we are working on, it's my oldest son's 72 Challenger Ralley. It's an original triple black car - black paint, black vinyl top, and black interior, 318 car with R/T hood, console, buckets, and ralley dash. The engine is the original 318, freshly rebuilt and we put 360 heads with 2.02" intake valves. My brother bought it from someone that we knew back in high school that was the second owner. He drove it a while, and then sold it to me. Then I drove it for a while, then sold it back to my brother. He has now handed it down to my son. It has just under 100 k miles on it.

View attachment 1714749034

Now you know how to properly splice electrical wiring. Good luck with your projects. I hope that this will help you if you need to splice any wires.
Click to expand...

can`t believe some one would need to be told this!
 
No need for flux on electrical wiring it's used more in plumbing for flow
and to help the solder adhere to a cheaper grade copper
 
Thanks KrazyKuda. I have been splicing wires for many years sometimes the right way and sometimes the wrong way. But it was good to hear how it is done properly.
 
here is some real nice shrink wrap. a lot nicer than the crap you get at the local parts store.. http://www.tiewraps.com/dualwall.html


another tip ya can add is when you are splicing more then just one wire in a bundle is to stagger the splices so that when taped all back up the wires sit better.
 
abodyjoe said:
another tip ya can add is when you are splicing more then just one wire in a bundle is to stagger the splices so that when taped all back up the wires sit better.
Click to expand...

Yup, that's an excellent point. That way your wiring doesn't look like a snake that just swallowed a rat.
 
dodge71demon said:
No need for flux on electrical wiring it's used more in plumbing for flow
and to help the solder adhere to a cheaper grade copper
Click to expand...

You need to use flux. But use rosin core solder as the rosin is non corrosive. Acid based flux is for use on copper plumbing joints. Dan
 
Great thread for beginners. Always wipe the flux off with a damp rag or alcohol after soldering, it will enhance corrosion. Here is a link to the military wiring Bible that I have used by many years. Just a reference to use, definitely for all from beginners to advanced wiring. Hope it helps. [ame="http://navybmr.com/study%20material2/NAVAIR%2001-1A-505-1.pdf"]http://navybmr.com/study%20material2/NAVAIR%2001-1A-505-1.pdf[/ame]
 
I like to use the liquid electrical tape on the joints before the shrink tube. It really helps keep the elements out AND inhibits corrosion as it seals it from the air.

Paint it on with the little brush and let dry, then heat shrink.


Wire Splice 18-1.jpg
 
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Bad Sport said:
I like to use the liquid electrical tape on the joints before the shrink tube. It really helps keep the elements out AND inhibits corrosion as it seals it from the air.

Paint it on with the little brush and let dry, then heat shrink.
Click to expand...


I once had some shrink wrap with a "sealer" in it. As it shrunk, this clear gel would squeeze out of it and it would seal water tight. I got it from guy in the electrical lab, but I don't know if it's available to us "common folk". I've tried looking for some ever since, but can't find it at any stores.
 
krazykuda said:
I once had some shrink wrap with a "sealer" in it. As it shrunk, this clear gel would squeeze out of it and it would seal water tight. I got it from guy in the electrical lab, but I don't know if it's available to us "common folk". I've tried looking for some ever since, but can't find it at any stores.
Click to expand...

I used to do contract phone line work, and we used this a lot in outside applications. It seals and adheres to the wire casing. Pretty good stuff.

http://www.grainger.com/product/POWER-FIRST-Cross-Linked-Polyolefin-WP121199/_/N-8iiZ1z0kazg?_=1409054844255&s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/4RCT9_AS01?$smthumb$

You can highlight and right click, open link. For some reason it doesn't want to paste right.
 
Bad Sport said:
I used to do contract phone line work, and we used this a lot in outside applications. It seals and adheres to the wire casing. Pretty good stuff.

http://www.grainger.com/product/POWER-FIRST-Cross-Linked-Polyolefin-WP121199/_/N-8iiZ1z0kazg?_=1409054844255&s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/4RCT9_AS01?$smthumb$

You can highlight and right click, open link. For some reason it doesn't want to paste right.
Click to expand...


That looks like it. But dam, some of it's expensive...
 
Thanks KrazyKuda. I have been splicing wires for many years sometimes the right way and sometimes the wrong way. But it was good to hear how it is done properly.

What he said...
C
 
Bad Sport said:
I like to use the liquid electrical tape on the joints before the shrink tube. It really helps keep the elements out AND inhibits corrosion as it seals it from the air.

Paint it on with the little brush and let dry, then heat shrink.
Click to expand...


I've never seen that stuff. Where do you pick it up?
 
I get mine at my local hardware. I would think any "good" parts house would have it.

A can of it goes a loooong way.

I like it because it turns into a rubbery type of seal, couple that with the heat shrink and it does a pretty good job. When using the heat shrink over it, I always make sure the shrink tube extends beyond the liquid tape so that it actually seals to the wire casing instead of the liquid tape. When applying the liquid tape, I cover the exposed wire completely and extend it about a 1/4 inch onto the insulator. Let it dry and then proceed with the heat shrink. And if you feel the need, you can add a dab of the liquid tape to the ends of the heat shrink tube after it has been shrunk.

I discovered it when I was running several plow trucks and had to seal wire connections going to my external utility lights, and salter on the back. The road salt in the winter was terrible for causing the connections to turn green and corrode.
 
I believe that's called a "Western Union" splice.

I use electronics solder that has a copper safe flux core.

Way easier.

My biggest issue is forgetting to put the heat shrink tubing on before soldering.

I also have one of those cheap harbor freight "third hand" stands, but I removed the metal alligator clips and replaced them with clothes pins I modified to fit in the set screw holders.
That way the metal doesn't eat into the wire insulation.
 
Everyone has there own way of doing things. Some have learned through experience what works good and what works better in their opinion. Then there are those who use the word best to describe their method. You can just about bet they will chime in here shortly. Anyway...
Weather sealing heat shrink tubing is available. Even stores like Lowes have it but its found on a different shelf, and cut into short pieces.
Shrink and seal terminals and connectors are available too. Those features do cost more.
 
YY1 said:
My biggest issue is forgetting to put the heat shrink tubing on before soldering.
Click to expand...


Yes, I've done that also... More than once... :banghead:


That's when you go a little heavier on the electrical tape... :cheers:
 
RedFish said:
Everyone has there own way of doing things. Some have learned through experience what works good and what works better in their opinion. Then there are those who use the word best to describe their method. You can just about bet they will chime in here shortly. Anyway...
Click to expand...


This is how I've been splicing for years. It took years for me to get all of the details straight.

Like twisting the wires side by side instead of the "hook/loop" method.

Some people don't solder, but just twist the wires and tape them. I like the solder as it's more permanent and less prone to loose continuity.

I didn't learn how to clean and tin the tip of a soldering iron until I took classes on stained glass.


These are some of the tips that I've picked up over the 30 years of building cars.

Everyone has their own ways and opinions, this is how I do it, and it has worked well for me.
 
krazykuda said:
I once had some shrink wrap with a "sealer" in it. As it shrunk, this clear gel would squeeze out of it and it would seal water tight. I got it from guy in the electrical lab, but I don't know if it's available to us "common folk". I've tried looking for some ever since, but can't find it at any stores.
Click to expand...

Its a little pricy but it is marine or aircraft heat shrink, good stuff. Can be found at boat shops.
 
I do mine almost exactly the same way except with multiple strand wire I interlace, flux, then solder like this.

If I have enough bare wire I twist the interlaced part, then solder.
And of course heatshrink and even double heatshrink sometimes in areas with high abrasion possibilities.

I HATE lumps in wires. :)

Thanks for the info.

Wire Splice 30-1.jpg
 
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Good write up.

I mainly do the twist and solder method on my relay kit main power lines. Sometimes I crimp, not often. I found the crimps to be a lot larger in diameter than solder connections.

The tip about staggering the connection points in a multi-wire run is a great one. Keeps things much cleaner looking.
 
Depending on the size of the wire, sometimes I do this quite different. And, it depends on the wire layout. Sometimes I just twist the wires together as if I were putting on a wire nut.

Solder them

Nip off any sharp end point

Then heat shrink

If they are going opposite directions, just bend one back on the other

This works REALLY well for small stuff
 
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