Question about 240v 20 Amp Line

I have a simple question.currently I have two bedrooms near my room, both containing 15 amp circuits. so far that gives me around 30 amps to work with (80% of that obviously) now 30 amps is not a whole lot to me considering ill be running two 600 watt hps digital ballast, 460cfm vortex fan, two inline fan boosters, AC, Air Purifier, 8 bulb T5 for veg x2. anyways you see where Im getting at. heres where im stumped. I have a dedicated 20 amp 240v circuit at the other end of my place( on the other side of the house from my room)that I wanna use via extension cord going up through the roof, through the attic and down into my room.. giving me 20 more amps at 240v. that would give me enough power to throw three more 1000w lights correct? plus the only appliance that is plugged into this 240v is an old window ac unit and I never use the damn thing cause its shit. to me thats just Amps waiting to be used...Heres the issue, its tough to find a long enough extension cord to go from the outlet all the way over to my room. my first thoughts to this would be, do i create my own extremely long 240 v extension cord and possibly loose a certain amount of power on the way over? 2 thought, do I really go all out and hire an electrician and have him come over, add a sub panel and run that extra 240v 20amp circuit on over?? Would that even work? Is it possible to just pull the wires that are currently attached to the 20 amp breaker and to just add the new line to that 20 amp breaker and run it over to my room??? I hope someone understands this...cause im so pickled right now and I need to figure this all out soon, otherwise my room is on ice. just sitting there waiting to be cultivated in. help me out please. it will be greatly appreciated. thanks

Even if u can find a cord long enough dont do it , if ur drawing more amps than ur cord is rated for its gonna cause the wire to get hot and eventually the insulation will deteriate and then u will cause a fire! If u have to go that far get a coil of 12/2 romex(20 amp rated) and run it to your light from ur panel . at ur pael u will need a 2 pole breaker , there will be 2 screws on the side of it take the white wire to one screw and the black to the other it does not matter wich is wich! Then take ur bare wire to the ground bar or neutral bar it doesnt matter becouse it should be bonded if its ur main electrical panel. Im an electrician so Im not feeding u B.S. but be careful in that panel Id hire someone if u can but if attempting it urself thats what u need to do. Hope that helps!

yes just pull the wires for the a/c and use that breaker,like moshpit said use 12/2 and run your new line as short as possible.i would not even consider using any kind of extension cord.

Is it a 3 prong or a 4 prong? Most likely it is a 3 prong and here's the problem. If you were to turn the power to that receptacle off and open up the box you would most likely find 3 wires. A black, a white, and a bare ground. Unlike your standard 120v outlet, the white in a 3 prong 240v outlet is also hot, but on a different phase. That's how you get a 240v. Inside you breaker box, you have 2 "phases", an A phase and a B phase. From either phase to ground is 120v, but if you put a volt meter from phase to phase you'd get your 240v. I'm not saying to do this, just trying to explain how a house service works. If you have a 4 prong it is easier to do. Inside the 4 prong you'll have four wires. A black (hot), red (also hot), white (neutral), and bare ground. Either the black or the red to the white will give you 120v. You can do it with the 3 prong but it wold be advisable to change the breaker out.

listen to these guys, you don't want 240 volts running through an extension cord on that long of a run, make a new line from the circut box to your room. If your not sure how, Find the breaker that goes to that a/c, turn off,you should be able to pull the whole breaker towards you and out, once it's out,you can disconnect the existing wires and connect your new ones. reinstall breaker after completing your run.

Awsome help guys. I really appreciate it. Ill definitely consider hiring a technician if the task at hand seems to be too much for me. I am very handy when it comes to doing stuff like this but I do have a few more questions in regards to the wiring. So if I do understand correctly 12/3 will cover 20 amp line? From my breaker box to the room is approximately 30 ft. Ill need about that much wiring to run up the wall from the breaker box, into the attic, across the attic, then down through the ceiling into the room. Does that sounds correct? Is there supposed to be some sort of insulation for the wiring while running up the wall, through the attic, and then back down into the new sub panel??? Does anyone know of a good thread that will cover this situation step by step or maybe a book I could purchase on installing sub panel from the main breaker box? I also have another question. Seems that the 1 20 amp breaker is attached to another 20 amp breaker by some sort of clip in the elec panel. what does this mean? So no extension cords-CHECK And 12/3 wiring-CHECK. Any other advice would be very helpful. THANKS!!!!!!!

hey sonar. Yes it is a three prong, the male ac plug looks like this -- -- and the female outlet looks like this + -- ....(these are the tops of the plugs there is a third prong at the bottom)

so now what? Should I just abonden those wires running to ac unit outlet in the living room and go purchase some new 12/3 wiring and connect that to the breaker that the ac was originally in? So in my own mind this is how im seeing. There is 20 amps running through this line from the breaker to my ac unit outlet and thats it...I dont use this ac unit at all, so this is just a waste of 20 amps that I could be using constantly. So now if I can put this all together correctly...I go to home depot, purchase some 12/3 electrical current coils + another Dual 240v 20amp outlet....go home...install my new 12/3 wiring (obviously not connected to the breaker) up above the breaker box, up through the ceiling, into my attic, across the attic, down through the ceiling and down the wall above the new 240v 20amp outlet. I will then turn off the breaker in the breaker box that the 20 amp line is currently running on and detach it from the breaker box itself...Once its off I can remove the current 12/3 wiring ( no longer hot right???? I dont wanna melt!! ) thats connected to the ac line. I will then plug my new wiring into the breaker coming from my new 240v 20 amp outlet thats in my new g room. After it is installed I can then safely plug the breaker back into position inside the breaker box and switch it on? Let me know how this sounds and if there is something different I need to do. I will appreciate answers thanks!!!!!!

oops i guess i made some typos... 12/2 is what it is...

I'd go with 12/3 romex and install a sub panel in the grow room and split the load into two 120v 20A circuits. No sense in wasting a leg of that 240V.

how do i "split" the load into two 120v 20 amp circuits? I only have one 20 amp breaker thats running to my ac in the living room. Its completely pointless to have it on because I never use it. So what Im saying is why cant I just run that 20 amp line over to my new room with just a new 240v 20 amp outlet, buy some 240v power cords for my ballasts and walla???

To add the subpanel you are going to need to run 12/3. Put the black wire on one side of your dual throw 240v breaker. Put the red on the other. Connect your white to your neutral and green to ground. At your subpanel, run the black to L1, or line 1. And the red to L2. Connect your neutral and ground. And now you have two 120v circuits.

Personally I like to overdo it, so I ran 4 gauge wire out to my subpanel. Gives me upwards of 85 amps to play with. You can never go wrong with running bigger wire. Never go smaller though. I ran 10/3 for my 240v circuit from my subpanel.

If I understand your last post correctly, you are asking if you can run wire from your 120v 20amp breaker, to a 240v breaker for your ballasts.

That doesn't work. As explained earlier, household voltage runs on two 120v lines. That's basically how a breaker box is split up, into two sides. Line 1 and Line 2. A 120v breaker uses one side of that. A 240v breaker uses both lines. Understand?

alright so I just looked at my electricity breaker box and it looks like I have a punch out above my other breakers (1 slot only but usually fits two breakers in one slot correct?). So this is what Im thinking now. Should I go ahead and install a new 50-60 amp breaker to the main box and then run a big enough wire over to a sub panel breaker box located in the grow room. From there could I break up that 60 amps into 4 120v 15amp outlets? Or should i run my 240v 20amp wire over to the grow room and just place a 240v 20 amp plug outlet and use that with my 600 watt ballast's that both run 120/240v? just need a straight answer or what people prefer. setting up a sub panel sounds great but seems like too much work for what im really aiming for.