Custom Extension Cord

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Joined
Jul 30, 2009
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Location
Oldest inland city in America
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I want to make a single extension cord to run from my basement to
my detached garage for 220v and 110v. I want to pull from my
dryer receptacle or another 220v receptacle and circuit that I will
install. on the male end I want a 220v plug and on the female end I want a 220v and 2 x 110v receptacles.

I have 10/4 AWG stranded cable already and want to be able to
run 20 amps or less 220v power tools - table saw, band saw, etc,
220v phase converter, 110v welder, typical 110v hand power
tools, shop lights, 110v or 220v compressor ( each of these one at
a time of
course )

I have a general idea of how to do this, however I would like some
feedback on how to wire this up. or advice on where to research to double check my game plan.

I understand that this is most likely against electrical code and dudes are weary of offering advice because of legality - but dudes run this set-up all the time and I am basically going to do it anyway and want to be aware of all implications.

Thanks much in advance.
02.07.10 - 005.webp
 
Not an electrician, but I think it can be done easily. Be sure to oversize the wire based on the length. I would just run a 4 wire (1ground, 2 hot, 1 neutral) from your 220 supply out to the shop. At the shop end, it would probably be best to put some sort of junction box. In the junction box you would split off your 120v setup (1 hot, neutral, ground). You could make the box double as the 220 outlet also.

So you would end up with one long 4 wire, with a 220v outlet at one end. Out of the 220v outlet, have a pigtail to another outlet which will be your 120v.

I dont know if the 220v breaker at the house cares, but when you are running 120v stuff you will only be using half of the breaker, 1 hot. It may trip....not sure.

Hope this helps. Good luck!
 
So you would end up with one long 4 wire, with a 220v outlet at one end. Out of the 220v outlet, have a pigtail to another outlet which will be your 120v.

Do that, but make the pigtail for the two 120v circuits plug into the 220v receptacle. That way you (or your wife, or your buddy) can never use both 120v and 240v at the same time. The only problem I see is that you'll have a huge breaker for 120v stuff which means less protection for your equipment, but the breakers are only supposed to protect the wire anyway. Just make sure you use the appropriate wire/breaker size.
 
I have done this

Not saying this is hoyle. But it is safe providing are using a 30amp breaker. Note: I personaly would run 2 30amp single breakers. Not joined. (If one trips the other wont keep it from tripping.) If you get in a situation where you are running 220v and one trips. Guess what? what ever it is that is running will stop. cause you removed one of the potentials. and it takes 2 potentials to tango. I personaly wouldnt worry about having to big a breaker, for the 110v stuff you will be running. If you think about it most items you run are 5 amps or less anyway. Grinder trouble light etc. With a 20 amp circuit ( common) you have no protection for items with that low a draw anyway really.

IF it rubs you nads raw having to big a breaker for the 110 stuff
get 2 of theseBox Cover, 15 A - Plug Fuse Box Cover Units - Fuses - Electrical : Grainger Industrial Supply
with 15 amp fuses or go crazy and use 4 with 4 recepticles.
Anyway. is it legit? maybe not. Is it dangerous probably not.
Most likely you can add.
inform yourself of the amperage of the tools you use and count on fingers and toes if you have to. Over 30= trouble for you.

Have a nice weekend.
I want to reiterate do this at your own risk.
I have done it in the past with no Ill outcome.
juice.webp
 
Last edited:
Thanks for the advice.

Thanks for all the responses so far. Apparently this setup is slightly
more common than I expected. You all make a good point about the
amp draw vs the breaker setup to be used. I am now looking to add
a dedicated outlet coming off my main box for this usage as I
discovered that my dryer is grandfathered and has no ground. This
will allow me to not piss off my skirt by taking the dryer out of
commission and to run the ideal breaker setup.


Thanks again for the responses and if anyone has any additional
advice don't hesitate.
 
I just did something similar that I believe to be within code. I already had 110 in my garage and wanted 220 as well. I pulled an extra hot wire from the house. Using a double pole breaker, took the 1 hot from the original 20 amp 110 (single pole) breaker and the new hot and moved them to the new 20A double pole breaker (in the house). I then installed a "main lug" (a.k.a. subpanel) in the garage which takes the 2 hot wires for the main feed, the neutral gets installed into the neutral bar in the main lug and the ground goes to the ground bar. The ground and neutral bars SHOULD NOT be bonded together in the main lug (subpanel) From there it is quite easy to run 110v or 220v depending on whether you use a 110v or 220v breaker in the new main lug. My new main lug was a 4 space one so I ran 1 220v double pole and 2 110v single pole breakers. Again (disclaimer), I am not an electrician but was advised by one. Do this at your own risk or better yet, hire an electrician.
 
What wire size and type did you use?

My wire was run in conduit (plastic) underground. I used #12 wire as is code for a 20 amp circuit. So, 2 - #12 wires for hot, 1- #12 for neutral and 1- #12 for ground. I'm not sure but you may be able to under-size the ground and / or neutral by one size (#14). This all changes if you are running a long distance and have to account for attenuation. You may have to run #10 wire instead. My run was a bit over 50 feet and #12 worked fine though.

If you are going to trench wire out to the garage you will have to find some wire approved for use in the ground though. You can buy 10-3 or 12-3 which will give you 4 wires (always add one to the last number)

Again, disclaimer, I'm not an electrician.... own risk.... etc. :hillbilly:
 
Would it be that much more of a hassle to run a permanent power source out to the garage?

D
 
^^My thoughts also..

Pvc conduit and a main lug subpanel isn't going to break the bank.
 
Point Taken.

However my garage is separated from my house by an asphalt driveway that I share with my neighbors. My garage is approximately 30 ft. from my house on the nearest side. Conduit would have to be buried beneath the driveway.

That being said there are a pair of junction boxes in the basement with bare wires poking out (no current). In the garage there is a ghost mark of conduit running up the wall. I haven't able to uncover where the run from the house my come in.

I will have to get the sawsall out and dig deeper. I was looking for a 2nd approach that would be simple for the time being.

Thanks again for all replies. Lots of good advice.
 
However my garage is separated from my house by an asphalt driveway that I share with my neighbors. My garage is approximately 30 ft. from my house on the nearest side. Conduit would have to be buried beneath the driveway.

That being said there are a pair of junction boxes in the basement with bare wires poking out (no current). In the garage there is a ghost mark of conduit running up the wall. I haven't able to uncover where the run from the house my come in.

I will have to get the sawsall out and dig deeper. I was looking for a 2nd approach that would be simple for the time being.

Thanks again for all replies. Lots of good advice.

So the garage has no power at all? Sounds like someone ripped out the electric for some reason. That sucks.
 
Update!

Well today I tore out the **** poor carpentry work around the garage
door trim and sawsall excavated to find the original conduit. shop
vac'ed out the end, pulled the two wires that I found out about
0.25". Then twisted the two wires poking out of the junction box in
the basement and tested for continuity.

The boxes inside and out and the wires had been painted white when
the basement walls were painted. My house was previously a rental,
with hack jobs abound.

Good news is I was able to determine that i have a junction box in
the basement with two copper wires the poke out that are confirmed
to be the ones poking out of the conduit in the garage floor.

Now I need some more advice...

I don't think I can pull these wires back through the conduit to run
new wires. the wire in the conduit looks about the same gauge as
standard home romex wiring (12awg) and I think the run is around
40 to 50 feet.

My plan is to run a heavy duty switch box between my main panel
and the junction box running to the garage. I then will use a in line
type crimp on connector for joining the wires in the garage to
fresh romex to a junction box. From there I will run a line to two
sets of flourescent shop lights and I a 4 banger outlet box.


So it looks like 220 through an existing conduit is not going to be
possible. It seems like I can wire lights and power for the jambox
and maybe some hand tools. For the heavier stuff I suppose I
should still make the custom extension cord.


Feedback?

Thanks,

ANDY
 
Why don't you think you can pull the wires out? They should come out easily. My advice would be to tie a "heavy duty" masonry string to the end of the wires when you pull them out so you can use the same string to pull your new wires back through. Using a fish tape to pull the new wire back with runs of 40-50 feet sometimes get complicated. I used the string and had someone pushing the wire through on the other end at the same time. (Just don't break the string) and pull all the wires you need at the same time (2 hot, 1 neutral, 1 ground) Oh, and if you go this route buy some "clear glide" It's lube for pulling wires. Typically sold in the hardware store by the fish tapes and other wire pulling stuff. If you go this route let me know and I'll give you tips on how to properly "use" the string if you get stuck. Also, you will not be pulling romex through the conduit. Just regular 12AWG THHN wire sold on a spool.

Otherwise, if you re-use the wires and plan on using an inline crimp connector... I would advise against that unless they make one specifically for 120v household current (I don't think they do). You need wire nuts and electrical tape to properly connect the wires. Nut the wires and then tape the nut onto the wire.
 
I will get some pics later tonight.

I have a couple more thoughts on the task at hand. I think I am going to blow compressed air down the conduit from the garage side to see if I can clear out the conduit a bit.

Do you think it would be a bad move to spray or pour some PB Blaster or WD40 etc down the conduit to try to loosen things up prior to attempting to pull the old wires out?

Also what is the preferred method of attaching a string to the old wire as I pull it out?

A dude at work told me about a "chinese finger trap" type of sleeve that tightens as you pull.

I will try to post some pics of the situation ASAP.

Thanks once again for good feedback.

ANDY
 
I would not put anything flammable down the conduit. I don't know why but it just seems like a bad idea, plus the PB or WD-40 might eat away at the coating on the new wire (more likely the PB). If anything, you can use the wire glide gel I mentioned earlier. The wires should pull out pretty easily once they get going. I guess a pic would help because from what you are saying it sounds a lot more difficult than it should be.

Basically, for the string just make a loop at the end of the wire, tape it shut good, and then make an identical loop with the string and attach the two. Pulling the old wire out with the string following shouldn't be too bad as far as the string coming off goes. When you pull the new wire, you are going to take the first wire and form a loop at the end to attach the string to. You will then tape each additional wire to the first wire in a staggered fashion, going down the wire. Your goal it to make the wire as "skinny" as possible while still pulling all 3 (4 for 220v) down the conduit at the same time.

Also, I can't stress the importance enough of getting a heavy duty string to do this with. Especially with a run of 40-50 feet. The wire will pull nice at first and get almost "stuck" towards the end. Like I said earlier, I used heavy duty masonry string. If you are not sure what this is, google it. I got mine at ACE hardware but any hardware store will sell it. There are different strengths so make sure to get the havey duty one.

The method is to have someone on the feeding end putting the wire lube (be generous) on the wire as they are feeding into the conduit. There will come a point where they may have to "push" the wire in as you pull on the string. Imagine the string as a rubber band (It does have some give) Just stretch, release the tension, and stretch again. That's how I got mine 50' underground and around about 4 bends. You may want to practice outside of the conduit with a long piece string and some wire just to get a feel for how it will work.

I will try to take some pictures of my "pulling end" of the wire as I'm sure it's still laying around with the string attached as I just cut that part off when I was done.

As for the "finger trap" type things, I've seen those before but you still need to get something in there to pull with (string)
 

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