Yesterday I stopped in a Goodwill store and found a 100ft, 14 gauge extension cord... for $15! I looked it up online and the same exact cord sells new for $40-$80 depending on where you look! I love Goodwill :) My wife was a little irritated that I bought it since we already have several cords but none of them are this heavy duty so I couldn't pass it up. Then, last night, I was geeking out on here and I noticed the tools competition, so of course I had to make something I've been wanting to make for several years. I trash picked a wire spool a few years ago and ever since i've wanted to make an extension cord reel with built in electrical sockets like my dad made years ago. Only I had ideas on how I would improve the idea.

His has two sockets in a metal electrical box mounted on top of the reel, with the cord run inside and up to the box. I wanted my sockets to be inside the reel because the box always seemed like it was in the way when winding up the cord. I also wanted a knob for winding it up and a base so I can set it on the ground and just pull the cord to the outlet. I also wanted the base to be a hand hold for winding it back up.

This morning I stopped at my local home improvement store and started searching for parts. It took me a while but I eventually found all the parts I needed. I already had the cord and the spool and I had a wooden knob from a piece of furniture I fixed up. Oh, I also used a scrap of household electrical wire and a wire nut, both of which I already had.

I ended up buying:

(2) tamper resistant duplex outlets

(1) two gang electrical box

(1) metal outlet cover

(1) PVC toilet flange

(1) PVC toilet flange extension ring

(1) 4 inch PVC adapter

totaling $18.30 after tax. I ended up not using the flange extension ring so that takes off close to $4 after tax and puts the total spent right around $30, if you include the cord. I also used a few fasteners I already had on hand.

The tools I used were:

Jig saw

oscillating tool

drill with bits

philips and flathead screwdrivers


sand paper

wire cutters

regular and needle nose pliers

multi meter


A couple helpful comments have been made by some of our knowledgeable cohorts. They pointed out that if the cord is used while coiled around the spool, especially at a high power load, the wire will be subject to an effect known as inductance. Basically, it creates a magnetic field which then affects the conductor and if the current is high enough it can cause the cord to overheat. If you want a more in-depth explanation, there is a link below where you can find a ton of info about. You can also look in the comments to see an photo of a cord on a spool that overheated.

Long story short, if you are using an extension cord it is best to unwind it completely when you use it, especially if you are putting a high load on it (i.e. welder, lathe, electric heater, microwave, (most power tools and appliances really). These examples are not the only things that can draw a high load, check the power ratings on a tool or appliance to be sure. I've also included a page that has common power consumption ratings, it gives a good perspective of how different tools and appliances stack up.



Step 1: Cutting the Holes

First thing I had to figure out was "how is this crap gona fit?" I used the jigsaw for this part.

It took a bit of finagling with the size of the hole to be able to fit the parts through without making the hole too big. In the end I had to make it bigger than I wanted so I used a scrap piece of hard board as a mounting plate. (I forgot to mention that before. I also had that on hand.) I forgot to take a picture of the mounting plate after it was done. I sanded the edges of it help it look better. In retrospect, I wish I had cut a bigger piece and made the mount plate round to completely cover the metal tabs on the top of the spool. I could have cut a larger hole which would have made things a little easier later on. I also cut a couple tabs off the electrical box.

I also cut a bigger hole on the other side to fit the flange. Be careful with this part, my blade went off track a little and the hole ended up not being as round as I wanted it.

<p>You could cut an extra board, roughly the same diameter as the spool, with a handhold that sticks out beyond the spool. Then mount the spool to it with a 'lazy-susan' bearing.<br></p><p>http://www.amazon.com/Susan-Bearings-Thick-200-lb-Capacity/dp/B0006LBVDI (See also: Lowes, Home Depot, etc.)</p>
<p>The inductance is trivial and regardless is not responsible for any cord heating. However a coiled cord subject to heavy loads/current will get hotter than one that is not coiled. Standard wire tables usually include the current ratings of bundled versus free air wires. Just google it. </p>
<p>I appreciate the info about inductance - I was trained a lifetime ago as a flightline electrician on military aircraft, and my dad was a commercial and residential electrician, and it still didn't occur to me that this could happen. I've been anxious to find a reel that doesn't cost an arm and a leg but now wonder if I ought to just leave it alone...</p>
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<p>I think your project is a good idea but it looks like the cord you used does not have a ground prong. This could be a lethal mistake. </p>
<p>It does have ground. It is hiding behind one of the hot prongs in the photo.</p>
<br><br>Inductance is a non-issue. The current in the hot and neutral wires is balanced, so the coil has an exactly equal number of clockwise and counter clockwise turns. <br><br>There IS a problem with using a coiled cord: Heat can build up due to<br>lack of air cooling. The heat is proportional to the square of the current, so a 10A load heats the cord 4x as much as a 5A load. Once the cord begins heating, the resistance increases, which causes even more heating. When the cord gets hot enough to damage the insulation, the conductors can short, causing a catastrophic failure. Even if this does not happen, a hot cord can drop enough voltage to cause performance problems.
Ok, that makes sense. So the magnetic fields created by the two conductors would counteract each other?
<p>Pretty much. There will be a strong field _between_ the two conductors, but not around the pair. If you have ever used a clamp type ampmeter, you will get no reading if you place it around an extension cord. To get a reading, you have to place it around a single conductor.</p>
<p>That's pretty awesome, but mount it on bicycle wheels and it would be legendary! Ooh, I have some crappy snowblower pneumatics that would be perfect. </p>
<p>This is a nice project. This is something you wish you had when you really need one. Excellent!</p>
<p>loove it</p>
<p>Very nice instructable. Having built a few of these myself, I appreciate <br> your method. I believe I will use your method next time I build a cord <br>reel. I would note: if you pay $120 for a 14ga. 100 ft. cord, you are <br>paying waaaaay too much. Try $39.97 at Home Depot. It's only $84.97 for a <br> 12ga. cord. So you actually got the cord for a little under half price. <br> Then the biggest problem with a 100ft. 14ga. extension cord is that it <br>will only support a moderate (around 5-6A.) without a substantial drop <br>in voltage. I use a 100ft. 12ga. extension cord for my 18&quot; electric <br>chainsaw which draws 14A @ 120V. A few weeks ago, I cut the cord so I <br>had to resort to a 14ga. one. There was a distinct difference in the <br>speed of the motor with the smaller cord and the smaller cord will get <br>warm. BTW the wider terminal (usually marked with a silver colored screw) on the outlets gets the white wire.</p>
<p>Thanks</p><p>I see what you mean about the price. Even know when I look on Amazon I don't see it listed for $120. There is a listing for around $80. Maybe the seller was trying to gouge the price or maybe that price was for two of them. Who knows. </p><p>This is the thickest gauge cord I've owned so far. The other two main cords that I own are a Rigid(probably 16ga.) and a super cheap cord thats probably even smaller. I've never ran anything off of them that draws that much power. If I'm doing the right math your chainsaw is pulling about 1,600W. I mainly used them for a 1/4 in drill, small miter saw, and a cheap airless spray gun so i'm not sure I've put enough of a demand on them to make a difference. I'll be sure to remember that for the future though. Thanks</p>
<p>Thanks for the comments! </p><p>I'm trying to think of how it can be modified so the outlets are stationary. I have an idea but thats going to require a bit of tinkering to figure out though.</p>
<p>You are going to need a slipring assembly. Making one of those, especially for line power, is not a trivial task, involving laborious lathe work with brass, sliding contacts, and insulating material that encloses the entire thing. Been There Done That (almost)! I made a 96 channel slipring for work, but it didn't carry hazardous voltages. It took me a week, and that was after I designed it.</p>
<p>Thanks for sharing your experience. I figured it wouldn't be a simple task and based off your input probably beyond the scope of the tools I have without creating something potentially dangerous. </p>
<p>T14tedds and JasonJ1</p><p>Very good point about the effect of inductance on the coiled wire, thank you. It hadn't occurred to me with this but I'll make sure I keep that in mind when I use it. I'll update the instructable to mention that as well.</p>
<p>If your going to use this cord you should stretch it out full length while in use then be glad you have something to rewind it up on.</p>
<p>Ok some of the things you should be careful of, is the amp draw (High), length of cord(over 50'), and size of wire in the cord(#14). With a cord coiled up, you will induce the magnetics lines of force (EMF) to the adjacent conductors of the cord and create a transformer like effect with a big load. The cord will catch on fire.</p>
<p>It is worth adding a note to say that it should always be completely unwound before using it. Coils can build up heat that can cause a short. Image credit is to Joe Lynch - posted to dodgy techs facebook group. If you do use something like this then do not use it for high load applications such as power tools, kitchen items, heaters. </p>
<p>Can anyone tell me how I can edit this Instructable? I want to update it to add a caution about proper wiring but I'm not seeing a way to edit it. Is that possible?</p><p>In the mean time...</p><p>*CAUTION*</p><p>Electricity is dangerous so if you are not familiar with working with wires and how to wire an outlet, make sure you study up on that so you don't wire it wrong. The black and white wires should go to your power and the other (it was green in my cord) goes to ground. Here is a link to an Instructable with a video if you need a visual aid</p><p><a href="https://www.instructables.com/id/How-to-install-an-electrical-outlet/" rel="nofollow">https://www.instructables.com/id/How-to-install-an-...</a></p>
<p>If you look at a receptacle you should see what colors go to which terminals is printed on it. Plus the screws will be different colors too. Black (Hot) is brass, White (Neutral) is silver, and Ground is green. There should be a strip guide on the housing of the receptacle too. It tells you how much wire insulation to remove.</p><p>If you look at where you plug things in you'll see one slot is smaller than the other. The smaller slot is the hot slot. Face on it should be on the right hand side, if the ground prong is down.</p>
I didn't know about the strip guide on the housing, that's useful to know.
Nevermind, I found the link at the top on the right hand side.
<p>Nice score on the wire,</p><p>Looks like you're using a non polarized plug, that's not a good idea.</p><p>I see GFI has been mentioned, good idea and would require a grounded (3 prong) plug. I believe GFI would also offer some protection from a leak sourced from the other / a different buss with becomes amore an issue the3 longer the extension cord.</p>
Are you referring to the plug on the extension cord? Male end? I looked closely at the picture and it does look like it only has two prongs but it does actually have three. That is a good point to make, I wouldn't do this without the ground wire.
Oh, and the outlets I used are polarized. If you look real close at the up close shot of the outlets, one slot is bigger than the other.
<p>Nice project, just a couple of questions. 1.What's the knob for? do you actually turn the reel around your hand hold?</p><p>2. I you are turning the reel, doesn't the cable get twisted as you turn the reel?</p>
Yes, you stick you fingers through the flange on the other side to hold it, and turn it with the knob.<br> No it does not twist because the outlets are mounted to the spool so they turn with the cord.<br>When I get a chance I'll post a video of it in action.
<p>Sorry to be dense but never seeing the under side I can't quite picture how the &quot;hand hold&quot; bit works.</p><p>Apart from that I like what you did. As you mention in the comments, the deluxe version should have stationary outlets while spinning freely. Now THAT would be a wonderful thing. If you make one don't forget to let us know. Great stuff.</p>
<p>Oh, you're right! I'm the one that was being dense by not thinking to take a picture of that. I'd take care of that now but I'm out of town so that will have to wait.</p><p>I don't know when I'll eventually get the upgrade figured out. I'll have some free time this weekend so maybe I'll tinker with it then. When I do figure it out I'll definately update this.</p>
<p>Nice job. My only suggestion would be to use a GFCI for one of the outlets. It wouldn't work with the face plae that you have used, but it would have improved the overall safety of the cord reel.</p>
<p>Good suggestion! I could modify the plate for it to fit. I might do that this weekend, thanks</p>
nice job
This is a great idea
<p>I love the additon of the outlets! </p>

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