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I have a dilemma when it comes to setting up a good light show. Since I live in a rental property, it isn't feasible for me to have the house rewired to supply enough current for a display. Not to mention that the landlord porbably would not approve. My soloution is quite simple I think, and is where I'm looking for some expert opinion.

I do have access to a 240v receptical in my garage. I know that a single 240 on it's own is still not sufficent to provide the required power but, could it be done like this...

240v mains -> Transformer or other means of increasing power -> dedicated breakerbox->split 240v into 2 120v branches -> 16 - 20 20amp gfci's -> recepticals.

If this wold work then I could fabricate a wheeled metal housing with any required cooling for it.

I am anxious for any input you guys may have.

Thank You!

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Simple answer....no

There is nothing you can add that will INCREASE the amount of current available to you...

With that being said... you can convert a 220 source into 2-110 sources provided there are 4 wires (2 hot legs, a neutral, and a ground) and the amount of current available would be limited by the gauge of the wire going to the existing outlet. You may be able to put in a small subpanel if say you have 30 amps at 220, you could end up with 4-15 amp 110v circuits.(I strongly advise getting an electrician to help or do it for you before you attempt anything yourself though!)

You will most likely gain more by carefull energy management and limiting the AMOUNT of electricity required for your display.

(Using LED lights is one example to GREATLY reduce the amount of power required for example)

You didn't really mention how extensive you want your display to be... but I am using 32 channels of LOR and regular minilights this year and 2- 20 amp GFCI circuits are supplying the power for my display, and I haven't had any problems. I DID keep close track of the amount of current I was using and did my design keeping my limits in mind the whole time. (If I had used LEDs I would have been able to have a HUGE number of lights! LOL!)

Of course LEDs cost more.... so in my case keeping a close eye on my budget was my deciding factor also!

Remember... its not always about how many lights you have...

It's how creative you are and what you do with them!

And someday...you may end up owning your own home, and you can install as much electrical service as you want (or can afford!) and THEN do a killer no holds barred display!

I hope this helps!!!:happytree:

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You can wire a sub panel using the 220 volt wiring for a dryer, if it has 2 blacks a white and a green or bare ground. Do NOT try and wire it up as two 120 volt plugs using a black on each an sharing the white (neutral). The neutral carries the same amps (load) as the hot. Circuit breakers and fuses limit the current the hot can carry, but nothing protects the neutral from carrying twice its rated load.

Your best bet is to get a qualified electrician and let him look, you would be surprised what we can do sometimes!

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Thanks for the input! I have spoken to my landlord and the furthest that he is willing to allow me to go is to havea singe4 wire outlet installed (professionally of course and at my cost) next to the breaker box. My main breaker at the box is 200 amp. Since I can possibly spec this out, could it be a workable idea to have that outlet installed and use a SUPER HEAVY DUTY extension cord running to a remotesubpanel with gfci's? Is there anything that I should specifically spec to an electrician for the install?

Does anyone possibly have any other suggestions for my rental dilemma?

BTW... As for the planned size of my display, I PLAN on using 64 channels to start (the size of one control card) but, as my wife reminded me, I have a tendancy to never do things small! Plan now, save headache later.

Thanks Again!! :)

Part of all my questions ar because of what I found here... http://www.nooutage.com/PortDistrib.htm

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Not to nitpick Mike... but more to clarify...

Actually if the two hot legs on the 220v service are out of phase (which they have to be to provide 220 volts), then the amount of current returned on the neutral leg is always going to be equal to or lower than the amount of current in either line (black) wire. If the load on the 2 110 volt outlets was balanced (say both were pulling 8 amps) then the amount of current on the neutral feed wire will actually be zero!

That is why the main feed wires coming in to an electrical panel consist of 3 wires of equal size (sometimes in overhead feeds the neutral is actually smaller because of this!)

The out of phase currents from the 2 110v legs actually cancel each other when they return in the neutral, thereby reducing the amount of current to a level lower than present in either phase leg. Again, in a well balanced electrical panel the amount of current on the neutral will actually be quite low

Just FYI!

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Since my earlier post, I have tempered my aversion to shared neutrals. I still wouldn't wire up a house that way. It is true, that if on opposite poles, the neutral will not be overloaded, the worse case is one hot unloaded (or open) and the other loaded to the maximum - then current flows back to the source only through the neutral. Remember we are talking about house wiring for Christmas lights, this could happen, but probably with not much problem. On the other hand, if I flip the breaker to work on a circuit, I want both the hot and neutral to be dead, not me if I disconnect the neutral. You can share a neutral with 2 loads if the loads are connected to different poles. When connected this way the neutral will carry the difference between the loads..not the sum of the loads. If you were to get the 2 breakers on the same pole however then the neutral would indeed carry the sum of both loads. Just measure the voltage between the 2 hot wires..if it's 240ish then you're on different poles...if it's zeroish then you're on the same pole and that's not good. Not suggesting Erin shares neutrals, just letting him know it's possible if done correctly. Shared neutrals are fairly common in commercial work because everything is labeled, there are prints and pretty much only electricians work on the electric. Houses however...yikes.

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Actually I was refering to home wiring, but only when it is a 220v circuit. That way it is being fed with a double pole breaker which will always give you opposing phases from your buss in your breaker panel, and also assure that if you turn the breaker off it will open both lines so that no current will be present.

If you want to create 110v circuits from a 220v branch circuit you should ALWAYS use a subpanel with your single pole breakers and individual neutrals from THAT point out so there is no possibility of having voltage present on a branch neutral when the breaker for that circuit is off.

So in that respect I DO agree with you Mike, I would NEVER recommend a shared neutral on a 110v branch circuit, it is too risky. I was only refering to the 220v branch.

In Craig's case, I would have the electrician assess how much "headroom" he has in his panel and size a 220v branch from that with a 4 wire socket rated for that amount. Then you can do your plug-in subpanel from that.

Remember to equip your circuits with GFCI protection also!

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"Is there anything that I should specifically spec to an electrician for the install?"

Hi Craig. Your electrical requirements have nothing to do with the size of your extension cord or how many channels you are going to use. What you should determine is what kind of lights you are going to use and how many. If that doesn’t exceed the current ratings of the LOR boards required to get you 64 channels, then you should tell the electrician that you need a circuit for each board and the max rating for that board. He'll be able to look at your existing panel and determine if that is possible.

Mark

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"Actually if the two hot legs on the 220v service are out of phase (which they have to be to provide 220 volts)"

Hi Terry. I think you are using "out of phase" when you should be using "opposite polarity"when referenced to the neutral. The utility transformer that serves your house provides single phase 220volt service. The winding of that transformer is center-tapped to create two 120 volt windings and the center-tap is then used as the point to connect the neutral. So, the two voltages are in phase because they are from the same winding. With your engineering background, think of avoltage vector with a magnitude of 220 volts. Now divide that vector in the middle so that it looks like the addition of two 120 volt vectors; both point the same direction because they have to add to 220 volts. There is no phase angle difference between these two vectors. Does this make sense?

Mark

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Ok, so then I gateher that, upon further inspection by a qualified professional, a plugin subpanel MAY be an option. As far as "headroom" goes, I think I should be fine there because I remember the landlord saying that he had the service upgraded to 200 amp bacause he used to run a silk screening business from the garage and that is where he had his dryers and all hooked up. I guess that now I just need to figure out what my actual power requirements are, figure in a safety margin, and call an electrician.

As for the 220v extension cord, I had figured that to be super heavy duty as I hope to only run the one cord from the main panel outside to the subpanel.

Thanks to everyone for your thoughts on this!! :)

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terrypowerz wrote:

Actually I was refering to home wiring, but only when it is a 220v circuit. That way it is being fed with a double pole breaker which will always give you opposing phases from your buss in your breaker panel, and also assure that if you turn the breaker off it will open both lines so that no current will be present.

If you want to create 110v circuits from a 220v branch circuit you should ALWAYS use a subpanel with your single pole breakers and individual neutrals from THAT point out so there is no possibility of having voltage present on a branch neutral when the breaker for that circuit is off.

So in that respect I DO agree with you Mike, I would NEVER recommend a shared neutral on a 110v branch circuit, it is too risky. I was only refering to the 220v branch.

In Craig's case, I would have the electrician assess how much "headroom" he has in his panel and size a 220v branch from that with a 4 wire socket rated for that amount. Then you can do your plug-in subpanel from that.

Remember to equip your circuits with GFCI protection also!

I think we were saying the same thing only different ways!:D I just know that you have to be very careful when going into a house just in case someone has done a "helping job" ahead of you.

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