How to make a “super” extension cord (aka power distribution box)

How to make a “super” extension cord (aka power distribution box)


Hi Makers, Builders and Do-It-Yourselfers.
Harley here. My wife has this pile of miscellaneous chargers and wall warts and things that need
to be plugged in and she only has one outlet. It’s kind of a mess to be changing things
back and forth. It’s a messy pile; she doesn’t know what to do with it. Uh, she came to me
the other day and asked if I could help her find a solution. We went to some home improvement
stores looking for power strips and found some. Umm, nothing that really worked… that
we thought would work well with what we thought we needed in terms of count and spacing and
that kind of stuff. So, I had some materials left over, some outlets, some romex, some
wire nuts, some wood, and uh, from previous projects, and decided I’d try to make something.
I talked to her about all the things she wanted to plug into it, where she wanted to put it,
kind of basic specifications, requirements, types of things and started to work. And then
I took some scrap wood and make this box. The sides are made out of particle board.
The top and bottom are MDF. The back is plywood. The dimensions are based on what she needed
and constrained by what I had on hand. The… it was looking a little bit rough, so I put
a couple coats of black spray paint on it and to try to dress it up a bit. So, I picked
up some 3/4 by 3/4 by 1/8 inch angle aluminum and made some brackets for each row. I drilled
holes where I wanted the outlets and switches. And did a test on these supposedly self-tapping
screws on some scrap material. It worked fine. I started driving it into this material and
it promptly broke off. I got a punch and punched it out and a tap and then tapped all the holes
and everything worked fine then. I think this material was a little thicker than my test
material and it was just too thick for the self-taping screws. We’ve got switches for
each row to be able to switch them on and off independently of each other and a pilot
light to tell you when it’s on or off. So the next step was to wire everything together.
And we’ll flip this over and take a look at how that works. So these three lines come
from the plug. The white one goes to the switch for the pilot light and then around to the
white side for each of the outlets. The black line comes up to the switched, uh, unswitched
side of the switch and another black line comes from the switched side to the black
side of the outlets. We have the copper line that comes into all the green screws for the
ground circuit. Each outlet in the row is simply daisy chained to the one before it.
White goes to white. And black goes to black. And ground is simply looped around the green
screws. Starting at the switch and all the way down to the end. Now that I’ve shown you
the physical wiring, let’s look at a schematic diagram. There are three items in this device:
the plug, switches with pilot lights, and outlets. Starting with the plug, we have hot,
neutral and ground lines. The hot is black. Neutral is white. And ground is uninsulated
copper. The ground simply goes from one device to the next, connecting to the green screws.
The neutral goes first to the pilot lights and then to the neutral side of each of the
outlets. Next the hot goes to the switch. This switch with the pilot light can be setup
in several different configurations. In a future video, I plan to show some of the different
ways this switch can be used, but for the purposes of this project I want the light
to come on when the switch is turned on so I’m going to use the default configuration
here. The hot line goes to the unswitched side of the plug that’s not connected to the
light. Then I connect the switched hot side from the switch to each of the outlets in
succession. This means there’s no power coming from the hot side when the switch is off.
When it’s on, power flows to both the pilot light and the outlets. After I wired everything
together, I needed to make a cover for the front. I did this out of some 26 gauge sheet
metal and just cut 10 square holes for the outlets and switches. In order to do this
I used three cutting tools. First of all I used the standard, kind of scissors style
aviation shears. Uh, typical of what you use most often for cutting metal. Then I also
used some dual edged cutting nibblers, shears, it’s gone by a couple different names I’ve
heard. And finally I used some nibblers to really clean up the edges and get some precision
cuts. First, using a fine tipped permanent marker, a tape measure and combination square,
I laid out lines for the holes. Next I created a starter hole simply by using a large screwdriver
as a punch. Then I opened up the hole with the metal snips. Now with the larger hole,
I could use the dual edged snips to cut out the majority of the hole. I’d not heard of
this type of cutter until several weeks ago. It worked well to cut out from the middle
of the sheet. and there’s no curl in the metal afterward like there is with standard scissor-style
snips. However, they don’t work well on an edge if there’s not enough support. Also,
they have a kerf of about an eighth of an inch that you have to take into consideration
when doing your layout. After cutting out the majority of the hole, I went back to snips
for a bit of touch up. Final clean-up was done with a nibbler. These are like tiny shears
that punch out a small strip about a sixteenth of an inch by an eighth of an inch. They can
be very precise, but since they don’t take off much material, it take awhile to make
cuts of any length. So, the plan was to put some
pop rivets in here on each rail in between each of the outlets in order to hold the sheet
metal to the assembly underneath. But after putting in the cover plates, I find it’s not
going to go anywhere. It’s really solid. And, uh, if I just leave it the way it is, it’s
a whole lot easier to assemble, and if I ever need to take it apart in the future, it’ll
be much easier to, uh, take apart and make any changes if I need to. One thing I found
after I put the cover plates on, there are a couple places where either I mis-measured
or I cut too, too wide of the line, or something, or there’s enough variation in the manufacturing
of the cover plates and switches and all, that I have a couple places where I have a
little bit of the sheet metal line coming through. I’m not real wild about that, but
such is it in hacks. So I drilled a hole here for the, uh, cord to come through and vacuumed
everything out and put a wire tie on the cord to act as a strain relief so it doesn’t pull
back out and put pressure on the ends of the wire. If you don’t have one of these and you
do anything at all with wire ties, they’re really handy. They’re called a “zip tie gun.”
And they’re like I think less than $10 at Lowe’s or Home Depot and they work really
well. You put the zip tie in here and just kind of pull, it cranks down, pulls everything
tight, and there’s also a little cutter in there so while you have it pulled tight, you
can kind of twist, and it cuts it all off. It works really well if you have to do anything
of any real significance with zip ties. One thing I have found though is with these really
large zip ties, the cutter cuts really kind of too close and they have a tendency to pop
off. So on this particular one I just used a pair of diagonal cutters and cut it, left
about an eighth of an inch here on the end. So the next step is to kind of wire tie everything
together with wire nuts and then we’ll assemble the top and put on… we’ll assemble the top
and attach it permanently to the box. Ok. So I wire nutted the solid core wire coming
from the rest of the box to the stranded core wire coming from the plug. And just kind of
wire tied all three of these together. The green to the copper. The white to the white
and the black to the black. A couple things to keep in mind when using wire ties, particularly
with stranded and solid core wire; the stranded wire wants to wrap around the solid core and
so you need to strip off more length on the stranded than you have on the solid core.
And then as you’re tightening them down, you want to be tugging on each wire individually
and the cap as a whole to make sure you have a good solid connection in there and that
nothings going to come apart on you. Once it’s put together though, I’ve never had these
things work their way loose. They stay tight until you intentionally take them apart. Ok.
To hold the top on I got some angle aluminum to… that will go along the edges. One side
of this is one half inch and the other side is three-quarter inch. The… uh… I’d gotten
some equal sided aluminum before and found that I didn’t have enough clearance on the
front with the face plate on here. So I went back and got some that had different lengths
on the edges. But I think that… I’ll put some screws in on the sides on the long side
and I think that’ll hold that on there nicely. Ok. Got the edges on to hold the front on;
got some trim pieces on it; eased the edges with a file so they’re not quite so sharp;
added a handle, some feet. I think we’re ready to give this a try. Ok. So I have it plugged
in. There’s no smoke. The lights are still on. I think we’re good. Uh. Although the switches
are all off. I don’t have any initial shorts anyway. So I’m going to give this thing a
test. And I’ve got this little device here. I don’t know what they’re called but you can
pick them up at home improvement stores and I’d be surprised if they’re more than twenty
bucks. They’re really cheap. But they’re really handy when you’re working with 110 electrical
outlets. They’ve got three lights on them and they have one pattern that shows up when
it’s correct and five different patterns for five different error conditions like open
ground, open neutral, hot ground reverse, those types of things. Very handy if you’re
buying a house and you want to check, you should check your outlets before you buy,
so when you make an offer you can put conditions on it if there’s anything wrong, you can have
it fixed. If you’re doing your own electrical wiring you can check it. That type of thing.
For this I’ll use it to check my wiring in the box. So it’s real simple, you just kind
of plug it in and turn it on and viola, we have two lights that indicates correct. And
to kind of verify I didn’t get anything reversed as I went down the line, I’ll plug it in to
the last one and we still have to green, uh, orange ones indicating correct. Awesome. And
we’ll try the bottom one and turn it on. And correct. And turn this one on and it’s correct.
So, I’m assuming everything else is probably ok. I mean I could have something reversed
and then reversed back, but, eh, I’m not going to worry with it. The pilot lights all come
on. If we turn everything off, we should not have anything, and we don’t. So I… hey…
I think everything’s good, this is looking great. Time to go install it. So there we
go. We’ve got room for battery chargers. Other battery chargers. Wall warts. Expansion room.
Places to put other things that aren’t right here. Overall I think it’ll work well. So
until next time, go make something.

73 thoughts on “How to make a “super” extension cord (aka power distribution box)

  1. don't know about the safety standards in the US, but that bare copper looks really dangerous (even though it's a ground wire, in Europe, we use green/yellow insulated wire)

  2. You should have also mentioned not to load up more than 10-15 amps (depending on the circuit/circuit breaker) on one any distribution box of this kind, and to use a proper gauge cable to handle the amperage.

  3. LOL! Actually I have a Dremel and thought about using it. But I don't think it would have been faster and definitely would have been more of a mess.

  4. Yep. I thought about that afterward when it was too late to say anything. In our area, old construction is setup for 15 amps and new construction is 20 amps. Should be careful to not go over that, although the breaker should keep things from getting too out of hand if you do accidentally. All the wiring going to and in the box is rated for more than the circuit it's on, so the breaker is the "weak" link. I thought about putting a breaker in the box itself, but thought it was overkill for my use.

  5. ok, let me rephrase. Somebody please mail this guy a fiberglass reinforced cutting disc and a shop vac please. LOL either way turned out nice.

  6. well in what you guys call romex, we have a brown (live/hot) blue (neutral) & bare copper (ground), but when every you enter something where the cable is striped back (socket, fuse board light switch etc…) we then put a green & yellow striped cover on the ground wire

  7. muffler cutter from Harbor Freight, regularly on sale for $6.99.
    That'd be the ticket; just do it outdoors and it'd be done in a jiffy.

  8. Didn't find anything called a "muffler cutter" at Harbor Freight. Closest thing I could find was an air-powered 3" cut off tool at 9.99. That'd probably work, but you'd need a couple hundred dollar air compressor to go with it. 🙂

  9. Yeah, that's the official name for it. 47077 is the item number; they have coupons regularly for $6.99 sale price.
    An air compressor is really worth the price, you'll find it useful for a great many things. Buy one motor, and you can run a whole assortment of handy air tools with it.
    For some people, they may not have much use for one, but I get the impression you would be able to get some benefit from it.

  10. Thanks wingerrrrrrrrr. Yes, an air compressor is definitely on my wish list. But it'll probably have to wait until I get bigger/better shop space.

  11. For cutting those holes in the sheetmetal around 5:24, use a drill to make four holes in each corner, then use snips to connect the holes you drilled. It takes less time and does not look like hammered dog poo. Thanks for taking time to make this video.

  12. Thanks for the feedback fixedgearmike. That might work for some people. I tried that while preparing for this project but it was hard to get a clean cut on the line with the standard snips and they tended to put a bad curl in the metal. Of course it could simply be poor technique on my part too. Doing it as shown gave me a much better finished product.

  13. Canadian regulations are 12 outlets/lights per breaker MAX. They only suggest 10, so of you had a couple more outlets in the room and the overhead light, it would really be pushing it LOL

  14. Yeah, but this is an extension cord so it only counts as one. 😉

    When doing some remodeling a while back, I talked with a local building inspector about the maximum number of outlets on a circuit. He didn't care how many outlets were on it since the breaker would pop if too much current was pulled through the line. The wire was rated for more than the breaker so there wasn't any danger of anything melting down from simply too many outlets.

    But of course regs vary location to location.

  15. is there a video of those speakers behind you in the workshop, are they bought or home made speakers

  16. I bought those speakers quite a while ago. I haven't done a video on them but they could use some remedial work on them. Doing a rebuild might make an interesting topic for a future video. Thanks.

  17. Hole saw, hole saw, and again hole saw. Drill two overlapping holes inside your box marks, kinda making a MasterCard symbol which leaves only four small pieces of metal to remove. I do this all the time to add receptacles to the ends of kitchen islands. If not my method them a rotozip with metal bit leaves fantastic edged cutouts. Thanks for your vid and keep em coming.

  18. Thanks. Yep that would work if I had a metal cutting hole saw. I had a wood cutting hole saw I tried cutting metal with once. Notice the past tense. 🙂 I like the idea of a metal cutting bit in a rotozip; that would probably be really sweet.

  19. Another pretty cool addition to that setup I'm my opinion would be for it to be fed by a multi-circuit cord. For example a locking 14-30p or locking 14-20p as the supply plug. Granted most homes don't have those type of receptacles, however there great in a workshop of any kind. You have the ability to mix it up and provide 125v or 250v from one source. This will reduce single line demand while remaing portable. Your setup is awesome for a battery charging station but if only using one line as

  20. I would have had to do a total redesign to avoid the sheet metal work. Maybe plastic cut out with a Roto Zip or something else. That much sheet metal work with the added frustration that would end with more cuts and pricks and blood loss than I would want to deal with. – – Great Job!

  21. Sure, if sheet metal isn't your thing, anything thin would work: plastic, hardwood, 1/4" plywood. I was using what I had, plus it looked kind of cool in an industrial sort of way.

  22. Glad you didn't take it the wrong way! So many video uploaders are soooo touchy about anything less than praise. You do get the praise for a great project, although (I) HATE sheet metal working. Keep up the great information.

  23. Bought with the compact UPS so that "wall wart" power packs, which cannot fit side by side on a power strip, can be placed alongside the UPS, instead.
    here is the link to it in case anyone is interested: amzn.to14saecG

  24. Do not wire the plugs together.  if one goes out it will kill the whole line. Run a  hot to each plug using a pig tail of of a main line for each plug so that one does not affect the other.  plus the way its wired you are putting all the load of your power distribution box through the first plug making it more likely to fail.  

  25. Very cool project! Fein makes a multi tool that will punch cut and cut out those holes. I think dremel and chicago electric from harbor freight has one too. I really like the idea and am gonna try it out. Its got a little more "style" than a power strip and with a little craftsmanship on the wood work you may have a piece of functional furniture. Great idea, man!

  26. Cool Box, You Should Have Used A Band Saw To Cut out The Metal Squares For The Outlets, But Good Job!

  27. Awesome Power distribution box 🙂 if i could make a small suggestion…. try adding a Usb Charger to your chain so you can cut back on the clutter if you plan on using your box to charge cell phones, tablets, mp3 players etc.

  28. You welcome. I think when folks realize that each person is an individual, and accepts or rejects on that truth, everyone will be ok. I liked your distribution box because of the room between the outlets, extremely beneficial..Seasoned, ok, cool. Age is just a gauge..

  29. Cool project. im wondering, is this extension cord will be able to support pc, television and all other basic home electrical devices? if not, how to make one that can support those.

  30. Looks like a fire waiting to happen.  This device has no UL rating nor does it meet any national or local electric codes.  Run away. BK  SENDS…

  31. i cant help but notice that there isnt any main earth going to the front metal work (i know its going to the sockets themselves, but the main earth should be bonded to the case also. And there is no internal fuse? i know you guys in america have plugs that can handle 16a but theyre not generally fused, right?

  32. Its all good until your solid core melts down when there is a big amp draw. Also should be fused to prevent that from happening. If you really wanted to maybe put a couple rcdOs in the case.

  33. Wondering why not just use a thin cut off wheel on grinder for cut box openings. Be a lot faster. Not trolling. Just asking

  34. I think I would've added some type of protection at the unit, itself (I figure that pre-made power strips have a built-in circuit breaker for a reason). Maybe a GFCI at the beginning of each row?

  35. I like the idea, but I would attached the cord permanently to the side with cable clamp as it tends to rotate and some point of time it can rip the wires out of it's terminals with only the cable tie acting as a makeshift strain relief.

  36. 2:00 working with Aluminum is a lot different than other metal you might use. If your cutting a lot of it keep it cool or it could melt to your saw. just a tip that might help somebody.

  37. This box is super unsafe because:
    1. It is made out of burnable material (aka wood)
    2. The front is made of a conductor (aka metal)
    3. The metal front has bad earth connection?! (Deadly if one wire comes loose)
    The connection through the screws for earth is not good enough (aluminium will form a non conductive layer AlO2)
    4.The strain relief is joke for this box(should be done with screws)

     You don't seem to be a certified electrician and therefor should refrain from working with mains electric!
    If something happens with your device no insurance will cover any casualties!( fire,electric shock resulting in injuries or death)

    Somebody trying to make this box might have even more deadly mistakes in it than the one shown in this video(problems with terminals, wire, insulation ……)

  38. I've had thoughts of making something like this for quite a while now. I agree with some of the criticism, but its normal to see ways to make something better, safer etc. One thought I had was to make the first plug, a GFCI. Also the metal face plate looked hard to work with and perhaps it is a safety hazard. I applaud your video though. If I were to try something like this, I think I would try to make things more compact and not use the metal although I haven't thought of what i would use instead.

  39. Heheh, apparently the inspector commented that I have too many things plugged into my power strip in my bedroom … blah! BS! They are all very low power devices, taking only 20 watts max each, and then one laptop charger which is somewhere around 80 to 100W … -_-

  40. I suggest mounting an actual UL listed electrical box, inside the wooden box, in which to make up the splices… that way you can clamp the cords/wires into place so when the white tiewrap rots away and falls off, pulling the cord doesn't just yank the splices apart. You're not supposed to make splices in open air… they're supposed to be inside a (UL listed) box.

  41. Not going to comment on the wiring since that subject has already been beaten to death. However, when you cut the holes in the sheet metal, you actually did more work than you needed to. You should have made a small starting hole, just large enough for the nibbler and then used the nibbler to cut the whole thing. Yes, the nibbler is slow, but in the video you already used the nibbler for the entire perimeter of the hole, and that's exactly what you needed to do. Removing the majority of the material prior to the nibbler didn't speed anything up and didn't prevent you needing to use the nibbler anyway.

  42. not such a great channel name. house of hacks implies that You the occupants of the house are the hacks. just saying. good luck to you just the same

  43. Honey did you get that power strip I asked you to pick up for me?

    No but I did make this huge ugly- ass unsafe monstrosity for only about 10 times the price…

  44. As a master electrician I would strongly caution anyone from building this box. there are many NEC electrical code violations in the construction of this project.
    the first being that you have created an electrical assembly without listed electrical parts.
    the most dangerous violation is grounding, its a violation of code to the yoke of the electrical receptacle to provide grounding to the metal cover and mounting brackets in the box.
    the power cord coming into the box has to be through an approved connector CGB style connector would provide a proper insulated connection and strain relief.
    exposed electrical wiring can not be exposed to a combustible material (wood).

    many more code violations.
    the electrical code is there to protect people from injury. some of the code issues create a fire and an electrocution hazard.

    the idea of the box is not a bad idea, the execution of it is a violation of NEC.
    to make this installation code compliant, mount a metal cut in style box to the aluminum strips. run 12/2 romex from box to box with an approved clamp at each box. make all electrical splices in the cut in boxes. use a CGB style connector to come into the box. make sure that each cut in box is properly grounded. if this is done then you can have a safe code compliant box.

Leave a Reply

Your email address will not be published. Required fields are marked *