Introduction: Properly Splice Aluminum Wire
In this Instructable, I'm going to teach you how how to make proper aluminum wire connections to ensure that they do not heat up, arc, and/or catch fire like many improperly performed splices have been known to do.
Note that this guide will also work for splicing aluminum wire to another aluminum wire, as long as you follow the wire preparation steps for both of the wires.
Always make sure the power is OFF and test this with a non-contact voltage detector and a multimeter before doing any electrical work.
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Step 1: Tools & Materials
You will need the following tools and materials to splice aluminum wire:
- Q-tip or similar application device
- Electrical tape (optional)
- Approved aluminum to copper/aluminum wire nut (eg: Ideal purple "Twister" connector.)
- Aluminum wire anti-oxidant compound
Make sure your wire nut is an approved and listed wire nut intended for this purpose. Normal wire nuts will not work. It's alright if the wire nut has preapplied antioxidant compound. It won't hurt anything, but we will not b relying on it in this case.
Step 2: Get Your Wires
You'll of course need some wires to splice. They would of course generally be inside of a box in a wall or ceiling, but for this guide I'm using a couple of cut-offs from previous projects.
Step 3: Prepare the Wires
Before you perform the splice, you must first prepare the wires you will be splicing.
To do this, first take your sandpaper and thoroughly sand the exposed bit of aluminum wire, to remove any present oxidation that would otherwise ruin the connection. Next, you must take the q-tip and use it to apply a generous amount of anti-oxidant compound to the wire. Take the sandpaper again, and use it to work the compound into the wire. Afterwards, apply a little bit more without working it in, just to be safe.
If you're splicing aluminum to aluminum, repeat the above steps with the second wire. If you're splicing aluminum to copper, you may apply some of the antioxidant compound to the copper wire as well, as it most certainly won't hurt anything and will probably further ensure a good connection.
The image is of the prepared aluminum wire. It looks a little bit messy, but that is alright.
Step 4: Line Up the Wires
Line your wires up next to each other, using one of your hands to hold them firmly side by side. If one of the wires sticks out further than the other, use the cutting notch in your pliers (or simply a pair of wire cutters) to trim the longer one.
As you can see in the photo, I've applied some antioxidant compound to the copper wire as well, as described in the previous step.
Step 5: Twist Them Together
Use your pliers to twist the wires firmly together. You must ensure that both of the wires are twisted around each other and not one wire around the other while the second wire is still straight. This is critical to both the mechanical and electrical integrity of the splice.
Step 6: Add the Wire Nut
Finally, to complete the splice, you must twist on your wire nut. Make sure to press the wires in as far as they will go, and then twist until it won't twist any further (without extreme force). This completes the splice.
Optionally, you may also wrap one or two turns of electrical tape around the bottom of the wire nut. This tape should not be holding the nut onto the splice; if it is, you've done something wrong. I personally do this to prevent any foreign objects from entering into the wire nut (although this should never happen when properly installed inside a box). Mostly, though, it's just for my own additional peace of mind.
Step 7: What Happens If You Don't Follow This Guide Correctly
Your splice is complete now and will last as long as the house it's in if you've followed the guide correctly, but I've added this additional step to show you what happens if you don't follow this guide and just sloppily make a bad splice.
These are photos (which do not belong to me) of incorrectly performed splices which have overheated, caught fire, and melted. Stuff like this often happens because the wires themselves are badly connected to each other, so instead, the metal spring inside of the wire nut (which was never meant to conduct electricity at all) starts carrying the current instead, eventually heating up and catching the plastic on fire.
This usually happens if you:
- Don't twist the wires together
- Rely on preapplied antioxidant inside of the wire nut instead of your own
- Use the wrong wire nut
Please don't do any of those things, and instead follow this guide, not only for your safety but also to comply with electrical code.
Thanks for reading. Hopefully I've helped someone out with performing better and safer aluminum wire splices.