Extension Cord Outlet Box

I added an electrical outlet box to a home-built wooden counter, using a standard double-plug outlet, a surface-mount, single-gang box, and an extension cord.

UPDATE I have upgraded from a standard double-plug outlet to the safer GFCI Outlet. I haven't added any pictures, but you should probably use a GFCI outlet as well.

Note: I am not an Electrician, so this probably isn't up to electrical code. Be careful. Don't plug anything in until it's all safely sealed up in the junction box. Make sure to get a beefy extension cord. As a good rule of thumb, don't plug anything into an outlet like this that you wouldn't feel comfortable plugging into the original extension cord.

This project is also documented at:
My Personal Webpage
My Flickr Photoset

Step 1 Cut an appropriately sized hole.

First, measure the size of your junction box. You could also trace the size onto your surface, which is what I did. You'll then need to cut out the hole. It will be much easier to drill a hole, and then cut out the rest of the rectangular hole.

Since this was in my 'office' room, I didn't want sawdust getting everywhere. In the second image of this step, you can see how I folded a piece of paper to create a chute for the sawdust right into my garbage can. I didn't even have to vacuum after this project.

Comments

[aweirick]

is there a company that makes anything like this? im doing something similar only my dad has made me agree to only use commercial products and not make it myself

[matthewbeckler]

Well, you could always get a power strip and mount that to your desk. I know that some of the power strips I've had have nice slots on the back for screw heads, so you can put a couple screws into the wall/bench/etc and then slide the screw heads into the back of the power switch. That might work for you.

[Tumwatertechwhiz]

Raising the outlet completely defeats the purpose of having a fire box to hold the outlet. You would be better off to remove some wood from the bottom of the counter/desk so that the fire box mounts flush with the top of the counter/desk.

[MisterSlippy]

This is reasonably safe if you have 100V mains from a center-tapped supply (which gives you only 50V in any dead short to earth) but it's still gonna bite you if you spill someting on it. Can I just warn anyone in the UK and Europe (dunno about other countries) running 240V mains NOT TO TRY THIS!!! Seriously, it'll kill you. If you want a countertop mains socket, make it raised and angled and seal the edges of the socket and the mounting box with silicon sealant. In the UK particularly, you will then need to get an electrician to test and certify your installation or your home insurance will be invalid. Better still, get an electrician to do the whole thing - you're gonna have to pay him for a day anyway, might as well get some work out of him! We are SO over-regulated here, it's ridiculous!

[Derin]

in TR nobody cares about correct installation,not even the power company

[Derin]

why am i insulting my country *sits down on rr tracks and watches train coming towards self*

[Derin]

Ow,that hurt.I want to try it again! *Sits on train tracks and watches high speed train come* *WHACK*

[matthewbeckler]

TR being the Republic of Turkey?

[Derin]

yep

[Metrokillah]

Trebuchet03 is correct the voltage in the US is, like the UK, not centre-earth tapped and so following the law POWER=AMPS*VOLTS if the voltage is half then the current is doubled and the Watts/Power is the SAME.

[trebuchet03]

To the best of my knowledge -- power in the states is not center tapped. There's a 110 hot wire and a neutral at ground. You can safely touch the neutral wire at any time. That's why it's important not to switch these two when wiring (less risk of something bad happening from someone being stupid).

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Out of curiosity, why do you say 240 will kill you in this application? You'll get the same amount of power as a 110 line....

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I agree with everyone that said GFI :)

[MisterSlippy]

I was being dense regarding voltages! Sorry. You wouldn't believe I make 3-phase mains distribution systems after reading that, would you? lol I agree it's a good idea, but only to the electrically competent. I know most of you guys know what you're doing, but it only takes one electrocution to kick off a lawsuit, n'est pas? If I were doing this, I'd use IP67-rated screw-down plugs and sockets, just to be sure. And to be honest, it'd be such a hassle changing ALL my plugs and sockets to suit, I'd throw the whole thing away and just put a switched twin socket outlet on the wall ABOVE my workbench. Which I did! Oh, and I put a relay in it, slaved off the 12v from my PC, so when the PC is off, all the extension sockets are off! - Instructable some time soon, I promise!

[0.775volts]

If you work in an area with the possiblity of a spill, you should use a GFCI outlet. they're a bit more pricy, but you won't have anything to worry about as long as you have a proper ground.

[matthewbeckler]

Good call. I don't usually keep liquids in this area (it's right next to my computer), but I should probably replace it with a GFCI just in case. I only spent $0.39 on the outlet, so a few bucks more couldn't hurt.

[j626no]

Is that the 20th anniversary leatherman Wave? I have one too...never seen anybody else with it! thats awesome. this is a really good idea. i've thought about it before but never followed through. i'll have to use it this year in my dorm room.

[matthewbeckler]

Well, it doesn't say anything about being an anniversary model. I got it from my uncle when I was 6 years old, which was, wow, almost 15 years ago now. I think it's one of the original models, being that it's so old. It's been a great tool for me, although it's starting to wear. I need to send it in to get the pivot tightened on the can opener/phillips side, as those parts tend to fall out when using it as a pliers, and the smallest flat-head screwdriver tip crumbled apart the other day. Otherwise it's been great. As other people noted below, you probably want to at least use a GFCI outlet, and probably want to mount it vertically, like the outlets in the wall are. Even if you don't spill liquid into it, dropping bits and pieces of stuff inside can't be a good thing. I've since moved out of that apartment, and now just keep the box as a mediocre extension cord.

[Tedwards]

The GFCI is the best thing you can do at this point. GCFIs are the only device actually designed to save your life. However, just for your information, your project does violate several 2005 National Electric Code articles, which may or may not be enforceable at your location. 110.3(b) equipment needs to be installed & used according to it's listing (you violated the listing of the extension cord by modifying it. 406.5(e) receptacles in countertops cannot be mounted face up 400.8(1) & (7) flexible cords cannot be used as a substitute for permanent building wire & cannot be subject to physical damage 590.3(b) Temporary wiring is limited to 90 days There may be others, and these rules are subject to some interpretation. I thought everyone might like to know.

[matthewbeckler]

Tedwards, Thank you for an awesome reply. It's good to hear from someone who actually knows what they're talking about. A quick note of explanation, I'm moving out of this apartment in August, and in my next home, I plan to mount the box face-out, like most outlets are. Thanks again, Matthew

[matthewbeckler]

UPDATE Hello everyone! Yesterday I was at the hardware store and decided to grab a GFCI outlet to upgrade my project. I haven't updated any of the pictures, but I'm sure you all know what GFCI outlets look like.

[Bisco]

this is a nice project. since if its pluged in it's just functioning as an extention cord. so it really doen't have to apply to any electrical codes as its not technicaly wired to the house. but yeah with the gfi or maybe put a weatherproof cover on it or both. if you ever wanted to perminenly install this in your house all you would have to do is replace the single gang old work plastic with a metal old work and run mc cable threw a hole in the wall down to the outlet box(which may have to bereplaced with another metal oldwork box so the mc connector would fit. but i think its much better off like this. lot less work

[matthewbeckler]

Thanks for the comment! I forgot to mention it, but the wooden counter is a temporary installation in my college apartment, and will have to be removed by the end of this summer. It certainly is temporary. I'm already planning improved versions (vertical mounts, GFCI, etc) for the next place that I live.

[MisterSlippy]

Ah, I apologise then...I also just noticed that it's a plug-in extension, and not a permanent installation.....so..... Please ignore EVERYTHING I've said above, and replace it all with this simple phrase: "To increase the safety of this device, plug it in via a RCD circuit breaker" Sorry again, all.....that makes me 0 for 6 now, I think!

[AymericRdV]

I did not read all the posts (since I am supposed to study for my midterms),so I am not sure if it has been said. But best would be to use a GFP plug. Also they have very nice stainless steel plug covers that would look even snazier

[chuckr44]

This is a handy idea but in Michigan I'm sure it would not pass inspection. There are so many rules violated here it's not even funny. Just remove it before you have your house inspected if you sell your house. Michigan rules are VERY strict.

[RyanPotter]

This is a pretty good idea, but I wouldn't mount it flat like that. You could easily drop small bits and pieces or spill liquids into it when it's mounted horizontally, but it's a nice idea.

[mothflavour2]

Cool. I like this idea. Although, I probably would put a box around the underside, just for added safety.

[matthewbeckler]

By "put at box around the underside", do you mean another box in addition to the junction box already there?

[gadgeteer]

As Punkguyta mentioned, build a small containing wall around it, to slow down accidental liquid spills and to avoid flat sheets of metal sliding in between the outlet and an inserted plug....

[Punkguyta]

Yes this is up to code, but if you were a freak about it you could make a box around the outlet on the underside and make sure you're using a junction box that has tighteners on it to secure the wire coming out, I can't see it on your's but it looks like that isn't there on that junction box.