I am thinking of making a extension cord using multigang boxes and receptacles that will supply 240V and 120V. There will be 10 250V 15A Recepts and 10 125V 15A Recepts. The 125V recepts will be divided so five will go on the red hot wire and five will go on the black hot wire sharing the same neutral white wire. I will use a cord connector for 3/4" Knockout as the 10/4 wire that I will use is thick.

I am doing this project so I can pull 240V to use with lamps/ballasts that works at that voltage like my Brazilian SBMV lamp. Also it will be portable and will work on any Dryer receptacles in houses built after 1996. I can even get about 7,200 Watts to power my future light fixtures. Jace did a similar light up but could pull only 1,800 Watts on a 15A recept or 2,400 Watts on a 20A recept with only 120V.

Question is: Should the strip be fused on it or I can use the breaker at the panel? I could searched the answer in the NEC 2008 but dunno if it will have anything on a extension cord that plug into the dryer receptacle and uses duplex receptacle for 120V and 240V.

FGS, this opens up a huge can of worms.  It won't pass muster with NEC, that's for sure.  For one thing, "standard" (i.e. with knockouts) electrical boxes are not rated (read: illegal) for use in non-fixed applications.  So, you'd need to get the proper box with a threaded hub to use for this.  You're going to pay a pretty penny for a multi-gang version.  Then, there is the issue of strain relief.  Standard cable clamps aren't going to cut it.

You want to power this from a dryer outlet?  There are two types (240v; 3-prong) & (240/120v; 4-prong).  You won't be able to derive 120v legally or safely from the former.  You could get away with it on the latter, as you've mentioned is your setup.

If you do it, you had better fuse each receptical seperately using the rating of the receptical as your guide.  A 30 amp circuit breaker for the dryer will let 30 amps through, but your 120v recepticals are only rated for 15 or 20 amps.  See the issue?

It's late, or I would write more.  Not to say you can't do it & do it relatively safely - I've built stuff like this before.  But, you asked about the NEC...it's probably not going to fly, man.  I don't have my code book handy, or I would give you specific citations.

I talked to my instructor about this device I got under plans. They do make a cord connector that will fit in a box's knock-out. (I have it, from a friend.) One smaller is here. It's mentioned on the sixth comment.

The circuits are gonna be fused with 15A each. The two hot wires will split into four so I am gonna need 4X 15A fuses. Two will be for 240V and two will be 120V with one neutral line. (The neutral will not get much amps if I balance the two hots wires, say 5A for red and 5A for black which leaves 0A on neutral line. If its a little off the neutral will take it away.) I wonder if Lowes/Home Depot have 15A Receptacle with red face, I do know they have black. (The colors will represent each hot. That way I can balance the load.

The 240V will have their own 15A fuses and white faced receptacles.

As for the box I am stumped as to where I will find one. Maybe I can make a wooden box and use one side as the "wall" and use the boxes with knockouts. The knockouts will be inside the box out of harms ways.

The dryer outlet is what many houses and apartments have for 240V power. Its easier to have something portaple that you can take with you when you move. You don't have to break open the wall to wire an 240V receptacle which its something landlords absolutely forbibs. (Its a four wire receptacle.)



Whew! Definitely one big can of worms. I have a drawing I used on the computer of the wirings. (Can't upload it since it's a drawing and not lighting related.)

I would also add gfci to each leg of the 115V outlets, as well as to the 240V outlets. As a portable device, this will add immensely to the safety aspect, much more so than fuses. The biggest likely fault is to earth, not a current overload, so rather suffer the breaker tripping to save your life than the fuse possibly blowing in a few hours after you are cookef through.

My bathroom have GFCIs built into receptacles. Is there one for 240v in the same shape?

Do dryers cords have GFCIs in-line exist?

I would listen to Spencer! He is the best on this stuff dude, he knows a lot about safety, I talk to him for advices for my streetlight display...and making it safe.

I am not doubting anything he says.

What do you think of me making a wooden box of the size I want but the height the same thickness of the wall and install the outlets as if you were installing a new box on the wall without tearing it up. I am gonna use 1/2" Plywood for it.

As for GFCI. I can't find one for 240V only for 120V. The extension cord factory-made doesn't have them, so is it okay to omit the GFCI altogether since this is not gonna be used daily or in wet/damp location? The only GFCI for 240V is built into circuit breakers and those cost money and they can't be used with wires feeding through both sides of the breaker. (One end accepst wires but the other end is fitted on the blade at the panel.) Which is why I am using fuses instead of breakers.

Do home depot/lowes sells 240V Receptacles for 15A?

I know they sells 120V in black color but do they sell them in red? The colors will represent each color of the phase (red/black.) It will be needed in order to balance the loads. For the 240V I will use white since it uses both phases.
As for the metal boxes, I will use those that are over sized and can be ganged up.

US wiring uses prebuilt busbars, whilst the rest of the planet allows for using either a busbar strip or separate wiring. If you get a European DIN rail spec breakers and GFCI breakers you can wire them in. The breakers work fine on 120V ( they are actually rated for DC and AC operation, up to 400VDC in most simple magnetic/thermal breakers ) whilst the GFCI may not work properly on 120VAC.

I worked in a building where we had 3 mains supplies, a 28VDC feed, 400VAC 50Hz 3 phase and 115VAC 400Hz 3 phase, all with earth leakage protection on each supply. Only the 400VAC supply actually would trip, the others were outside the breaker specs for operation, but were connected anyhow. There was one instance where a incorrect connection was made, the aircraft systems did not survive the 400AC supply, total loss.

One of the EU members might send you a GFCI ( or earth leakage) for the 240V supply, and a few 15A breakers to preserve common looks, all to be mounted on a small DIN top hat rail. Here in South Africa the latest generation of E/L no longer require an earth connection, but they do not fit DIN rail, using a propriety mounting, which comes in strip form, easily mounted and pre spaced. Nice black cased breakers, with white toggles for breakers and green for disconnectors and e/l. Does not comply with US specs for obvious reasons, but is exported to Europe very successfully.