extension cord w/ 240v and 120v?

[Buickspec6231]

Has anyone made their own outlets/box to plug in their 240v extension cord into that also has a 120v outlet on it, like on a generator? If I am running a welder, I am also going to be using the grinder for surface prep or whatever. Trying to limit the amount of extension cords I am dragging around the shop floor. I was thinking I could just pull 120v off of one of the conductors for the 240V outlet and wire it to a 120v 15amp outlet in the same box. I am no electrical engineer and have limited experience with residential wiring. I'm sure it is more complicated than the doodle I have attached, but to me it makes sense. Also, I'm not opposed to a commercially available product, just can't seem to find one. Which could also be taken as a sign. Be easy on me if this is a terrible idea. I'm just brainstorming. The receptacle is wired with 6/3 from the box on a 40a breaker and the extension cord is 8/3. Combined total length from breaker to end of extension cord does not exceed 55ft.

 

[Hdonly0]

You should be using a four wire extension cable with two hots, neutral, and ground. I would also install one of these circuit breakers in your box at the cable end on the 120 volt receptacle. Otherwise you are running a 40 amp circuit to a 15 amp 120 volt receptacle.

 

[theoldwizard1]

A couple of years ago, there was a thread about a DIY power distribution box. This is what you want.

EDIT : I could not find it but this is the best way to do want you want.

• Your feed must have 4 wires and should have a NEMA 14-20 or 14-30 plug (locking or non-locking). @ hots, neutral and ground
• Buy a small (2/4 or 4/8 space/circuit) breaker box, preferably one that is surface mounted. Look for one that has a lot of extra space on the inside.
• Make cut outs on the side for NEMA 5-15 duplex receptacles and NEMA 14-20/30 outlets.

Install receptacles. Wiring will be very tight, but it is doable!

 

[Buickspec6231]

Are you recommending the 4 conductor wire plus bare ground so that I am not sharing the ground with the neutral on the 120v outlet? I'm much more comfortable with 12v automotive wiring where this whole neutral problem doesn't exist. Thank you for the quick replies and the component recommendations. The in-line breaker makes sense. I started looking at available units (after theoldwizard taught me what they are called), and I don't really want/need one the size of the commercially available units. I'm going to start pricing out what I really need and see how that compares to a store bought model. Learning as we go along.

 

[MattT]

Are you recommending the 4 conductor wire plus bare ground so that I am not sharing the ground with the neutral on the 120v outlet?

It's 4 conductors, including ground, all insulated. Typical color coding is black and red for your 240v legs, white for neutral, and green for ground.

 

[Buickspec6231]

That makes more sense to me now. I'm going to be adding this to my list of projects. So far it's looking like a way better plan.

 

[sberry]

Don't mess with this, run a smaller cord for a grinder. You need new outlet, new cord, extra overcurrent protection, gfci.

 

[driftpin]

Don't mess with this, run a smaller cord for a grinder. You need new outlet, new cord, extra overcurrent protection, gfci.

This sounds better to me, anytime electricity is involved, better to be safe than sorry. You could probably jury-rig something but rather than 'share' a hot lead, having the right configuration sounds like a better choice to me.

Couldn't you just zip-tie the two cords together, if you want-to keep things neat?

 

[Bretny]

Not worth the trouble. Run a separate cord. How often do you like plugging in and unplugging cords?

 

[wyliesdiesels]

Have you ever seen a spider box?

Usually they are fed 208Y/120 50a or 100a and then theres individual breakers for the 120v outlets.

You would need separate overcurrent protection for the 120v outlet.

 

[killahog]

Don't mess with this, run a smaller cord for a grinder. You need new outlet, new cord, extra overcurrent protection, gfci.

Berry, I am watching the thread because I am contemplating a similar project ,I am curious would a gfci be required.

 

[Falcon67]

I'd run the main to a 4" box with the welder outlet, then split off to a quad with a GFCI and the bitty breaker pictured above. Done.

 

[Lonnies Performance]

Build a 240v extension & use one of these.

 

[sberry]

The only way that is legal is if it is plugged in to a 20A circuit. Maybe not even then since it now is not gfci.
If I am on projects often the grinder cord really isn't long enough anyway. It would need to be plugged in with the cart and machine close to the work and not allow much movement.
Outlets on fixed benches is good, other than that a cheap orange cord. Lay it along the same pathway as the welder cord if that's an issue, often it doesn't have to come from the same direction. I have economy cord reel in a couple places, can even put those overhead.
The fact that I can build any of this I want,,,,,, am a gadget builder,,, and don't says a lot. Especially as I refine,,, get a little older, find out simpler is good and maybe better. I actually got rid of a lot of that type of stuff during remodels. Don't need to use every fitting they ever invented.

 

[theoldwizard1]

Are you recommending the 4 conductor wire plus bare ground so that I am not sharing the ground with the neutral on the 120v outlet?

It's 4 conductors, including ground, all insulated. Typical color coding is black and red for your 240v legs, white for neutral, and green for ground.

In "portable cordage" (the industry term for extension cord wire) they count all of the conductors including the ground. Matt is correct in that there are not "bare" conductors.

 

[theoldwizard1]

Build a 240v extension & use one of these.

The only way that is legal is if it is plugged in to a 20A circuit.

I can't tell for sure, but the plug looks like a NEMA L14-20, hence it is legal.

This one is NOT because it would allow 30A on any of the 120V (NEMA 5-15 or 5-20) outlets

240V L14-30 3 ft Twistlock Adapter

 

[sberry]

Ya, I have seen a couple of these gems at fleas, not a bit of writing on it. Another 30 to 15. could plug a power strip in to it I spose.
Wiz,,, that one you posted says UL, wonder how that is so? Maybe someone with minds greater than our own can explain it? seems like there would need to be a breaker. They say something about generators, wonder if there is something around that?
I don't recall any overcurrent on welders, cant recall if they had something internal self resetting etc. My helper is gone a couple days, I will have to ask him. It seems I wonder that before but didn't ask anyone. I am sure someone here knows.

 

[wyliesdiesels]

Ya, I have seen a couple of these gems at fleas, not a bit of writing on it. Another 30 to 15. could plug a power strip in to it I spose.
Wiz,,, that one you posted says UL, wonder how that is so? Maybe someone with minds greater than our own can explain it? seems like there would need to be a breaker. They say something about generators, wonder if there is something around that?
I don't recall any overcurrent on welders, cant recall if they had something internal self resetting etc. My helper is gone a couple days, I will have to ask him. It seems I wonder that before but didn't ask anyone. I am sure someone here knows.

Wheres the U/L wrap around sticker?

I dont see one. Maybe i missed it...

 

[dscheidt]

What's wrong with attaching a 120V cord to your 240 cord with tape every couple of feet? It rolls up and goes out as a single element, not much more work.

 

[sberry]

Wheres the U/L wrap around sticker?

I dont see one. Maybe i missed it...

It said it in the ad.

 

[wyliesdiesels]

It said it in the ad.

Aww ok.

It says U/L approved which is the wrong terminology.

I doubt its U/L listed.

I asked for the U/L listing number...will see if i get a correct response...