which is better 240v or 120v

I have a unused drier connection in my basement I'm running 4 600's from 120v'ers I think could run them all to the 240v. cause I've heard it uses less power and you can hook up more lights. I'm not sure on amps its either a 40 or 50 amp I would just need to flip the breaker with the old drier going. does it make a difference on the volt or what ? and how would I wire 4 lights to it I think I can wire to a timer and run the timer through 4 outlets but I'm pretty sure I'd need to cut the drier outlet off and to rewire it there is about 3 feet of play plus I think I would pull the wire further down the wall to a more idele spot with the 240v wire I know a little bit about wireing I know I can do it just don't know the best way to do it and if I would really save power

I run all my lights on 240V outlets. each one is on its own 20A circuit. It is a little overkill IMO, but I can always double up on breakers. My flower room has 4 600s as well. If I were to do it again instead of having 4 outlets on separate breakers I would just get a light controller, and wire it to the panel. That is what I would suggest, if its an option, but you would need an electrician to tie it in to the panel if you dont know how to do that.

First step is isolate the breaker to see amperage available.

I could be wrong, but I believe the power usage will be about the same. 600w is 600w, the advantage of 240v is less amperage draw. For example (these numbers are for reference only, I'm making them up) If a 600w light draws 15A@120V it might only draw 10A@240v so you could run 3 lights on a 30A 240v circuit vs. only 2 lights on a 30A 120V circuit. Hopefully an electrician can come and clear this up but I'm pretty sure that's the main difference.

its still pretty much the same. watts are watts. amps at 120 and amps at 240 are still near same when you consider two hotlines comingin on 240. biggest issue is cords and ballasts will run cooler. use the dryer outlet and free up your normal outlets.

bluntmassa1 said:

I have a unused drier connection in my basement I'm running 4 600's from 120v'ers I think could run them all to the 240v. cause I've heard it uses less power and you can hook up more lights. I'm not sure on amps its either a 40 or 50 amp I would just need to flip the breaker with the old drier going. does it make a difference on the volt or what ? and how would I wire 4 lights to it I think I can wire to a timer and run the timer through 4 outlets but I'm pretty sure I'd need to cut the drier outlet off and to rewire it there is about 3 feet of play plus I think I would pull the wire further down the wall to a more idele spot with the 240v wire I know a little bit about wireing I know I can do it just don't know the best way to do it and if I would really save power

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What he said.

220VAC will produce less waste heat than 115VAC, which means, less power used.

High power appliances work best on 220VAC, so do high power lights.

Sentinel HPH-4 High Power Hid Controller
Product Number: ENV-HPH-4





When trying to control more than one HID lighting system, you can either use a bunch of timers OR the HPH-4. The HPH-4 makes it simple to control up to 4000 watts of lighting from a single timer or controller. The HPH-4 has FOUR UNIVERSAL receptacles that accept either a 120-volt or 240-volt male plugs from your HID ballasts. 30-amps @ 120 / 240-volt

I just saw this thing at htg supply it looks like all I would need to do is plug it in to the 240 volt outlet its out of stock but how do yall think this would work and does it only use 30 amps I only need 4 600's it says its good for 1,000

It will work but I would look at some American iron from a builder like dxsoundco.com before I put all my eggs in that chinese made basket.

Hugo Phurst said:

What he said.

220VAC will produce less waste heat than 115VAC, which means, less power used.

High power appliances work best on 220VAC, so do high power lights.

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Short Electrical Theory lesson.

You can calculate the difference you will see in amperage draw from a 120V circuit vs 240 volt circuit with Ohms Law.

Without getting too much into Ohm's Law one of the various useful calculation of Ohms law is Power = Volts X Amp's, otherwise written as P = E X I

WeedFreak78 said:

I could be wrong, but I believe the power usage will be about the same. 600w is 600w, the advantage of 240v is less amperage draw. For example (these numbers are for reference only, I'm making them up) If a 600w light draws 15A@120V it might only draw 10A@240v so you could run 3 lights on a 30A 240v circuit vs. only 2 lights on a 30A 120V circuit. Hopefully an electrician can come and clear this up but I'm pretty sure that's the main difference.

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We'll use the above numbers for an example.

If you have a 600 watt light, that in a perfect world used exactly 600 watts, using the equation above, and at 120v, you'd get as follows:

600 Watts = 120 volts x (I) ----> or rewritten as I = (600 watts / 120 volts) for a total of 5A.

There is no perfect world, and the electronics required in digital ballasts to modulate frequency, and regulate voltage all require power, in a conventional ballast you have transformer losses. So you have a loss of the ballast itself plus a 600 Watt lamp load.

Now apply the same equation to a 240 volt circuit. As superstoner1 wrote "its still pretty much the same. watts are watts". Even though we are moving to 240 volts, the load is still a 600 watt load regardless... watch what does change though.

600 watts = 240 volts x (I) ----> or rewritten as I = (600 watts / 240 volts) for a new value of 2.5A.

Notice that the amperage and voltage have an inverse relationship. As you increase the voltage the circuit draws less and less current.

On a side note, they actually manufacture 480 volt ballasts, in this circuit if you again double the voltage from 240 volts to 480 volts.... you probably guessed it by now, the current will draw just a mere 1.25 amps...

What does this all mean? The electric bill stays the same... your still using 600 watts either way, but don't dismiss the benefits: Smaller wires... less copper expense in the lighting circuits, more efficient movement of energy. The dangers? High voltage, the need for increased safety measures, especially in wet/damp areas. Most residential properties don't have access to 480 volts, its an industrial standard. But if someone were to be growing at a commercial property, and the cost of circuit installation was a concern, and a 480 voltage service was available, running high voltage ballasts could be an attractive option.

if you have a good understanding of electric you can build what you need for not that much. i build all of my switch panels, subpanels and relay setups, big difference in price and i know the quality is good, some of this cheap stuff they sale scares me.

hey blunt are you using an existing dryer outlet? is yours a 3 prong or 4 prong outlet? Im planning to get the powerbox dpc7500 240v with a 3 prong cord for mine. I'm still debating since i read somewhere that old 3 prong dryer outlets aren't safe. let me know what you decide on choosing. good luck!

it is three prong but its not the standard house three prong this house is only like 10 years old even the dryer up stairs has the same three prong and its a newer dryer about 5 years or so I don't see how it would be unsafe is it really not safe? I know I could hook up another outlet does anyone else think its unsafe to use a newer three prong outlet for 240v? I haven't really heard of a 4 prong outlet aint there only three wires in the 240v I know its a larger gauge wire but I'm pretty sure its about the same as a 120v so I don't see what the fourth prong would be for.

kamie said:

hey blunt are you using an existing dryer outlet? is yours a 3 prong or 4 prong outlet? Im planning to get the powerbox dpc7500 240v with a 3 prong cord for mine. I'm still debating since i read somewhere that old 3 prong dryer outlets aren't safe. let me know what you decide on choosing. good luck!

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ya right I just saw that one yesterday its out of stock so they don't even have a price I'll check that site though but this one don't look too bad its got a built in timer but I'm sure its not cheap

budleydoright said:

It will work but I would look at some American iron from a builder like dxsoundco.com before I put all my eggs in that chinese made basket.

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hey blunt this is the 3 prong dryer outlet i was talking about http://www.buildmyowncabin.com/electrical/how-to-wire-dryer.html there is also the 4 prong picture right below it. from what i read back in the day it was 3 prong dryer outlets until they realized it was unsafe and the newer homes were upgraded to 4 prong outlets.

3 prong should be - hot/hot/common?

4 prong would be hot/hot/common/ground?

correct? I know all this stuff, my lack of practical use keeps me a little rusty.

The difference between a 4 prong and 3 prong is that with the 3 prong you have two ungrounded "hot" conductors, and a bonded nuetral/grounding conductor. A 4 prong has the same 3 wires, except the neutral and equipment grounding conductor are run seperate, as they are required to throughout the rest of your house.

The white, grounded conductor, otherwise known as the neutral, carries the imbalanced load of the two hot conductors. If you are running just ballasts with the 240 volts you don't require the neutral, there is no unbalanced load to carry. HOWEVER, if you plan to take the 240 volts and separate the legs at a sub panel in your grow room, you'll want to run a 4 wire configuration, as its unsafe to depend upon the green equipment grounding conductor to become a path for current.

In older dryers they bonded the two together within the dryer, while the practice was legal for a number of years, new installations in most states require following the NEC, which has now been updated to require all 4 wire be brought to any dryer outlet, even if they are not used.

From a garden standpoint, bringing over 4 wires ensures that your grounding path, and your unbalanced current path are seperated. Technically they are at the same potential, and bonded back at the main panel anyway, but its added protection in the case of equipment failures. If for some reason the neutral were to open up, yet the ungrounded hot conductors did not, and the frame of a ballast became energized, you'd still have the equipment grounding conductor to take the fault current back to your main panel and cause the circuit breaker to trip.

I have yet to see a ballast manufacturer offer a 4 prong cordset. Either they are bonding the neutral and grounding conductor inside the ballast case, just as they did with older dryers, OR more likely, there is no unbalanced load and a neutral isn't needed.

so if I where to buy one of the light controllers from dxsoundco.com I should run a neutral wire and cut the outlet off and hard wire it? it seems like the same amount of work to change the outlet and I would need to pull it about ten feet down the wall to be in an ideal spot anyway. I shouldn't have a problem running a neutral wire from the box so this seems to be the best way to run all lights in the flower room and maybe more

Total.Hydroponic.Control said:

The difference between a 4 prong and 3 prong is that with the 3 prong you have two ungrounded "hot" conductors, and a bonded nuetral/grounding conductor. A 4 prong has the same 3 wires, except the neutral and equipment grounding conductor are run seperate, as they are required to throughout the rest of your house.

The white, grounded conductor, otherwise known as the neutral, carries the imbalanced load of the two hot conductors. If you are running just ballasts with the 240 volts you don't require the neutral, there is no unbalanced load to carry. HOWEVER, if you plan to take the 240 volts and separate the legs at a sub panel in your grow room, you'll want to run a 4 wire configuration, as its unsafe to depend upon the green equipment grounding conductor to become a path for current.

In older dryers they bonded the two together within the dryer, while the practice was legal for a number of years, new installations in most states require following the NEC, which has now been updated to require all 4 wire be brought to any dryer outlet, even if they are not used.

From a garden standpoint, bringing over 4 wires ensures that your grounding path, and your unbalanced current path are seperated. Technically they are at the same potential, and bonded back at the main panel anyway, but its added protection in the case of equipment failures. If for some reason the neutral were to open up, yet the ungrounded hot conductors did not, and the frame of a ballast became energized, you'd still have the equipment grounding conductor to take the fault current back to your main panel and cause the circuit breaker to trip.

I have yet to see a ballast manufacturer offer a 4 prong cordset. Either they are bonding the neutral and grounding conductor inside the ballast case, just as they did with older dryers, OR more likely, there is no unbalanced load and a neutral isn't needed.

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bluntmassa1 said:

so if I where to buy one of the light controllers from dxsoundco.com I should run a neutral wire and cut the outlet off and hard wire it? it seems like the same amount of work to change the outlet and I would need to pull it about ten feet down the wall to be in an ideal spot anyway. I shouldn't have a problem running a neutral wire from the box so this seems to be the best way to run all lights in the flower room and maybe more

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If money is no concern, and safety is. The safest and most efficient way to wire anything, is to code, and with the least number of mechanical splices. I consider a mechanical splice anything from wire nuts, to the bond between receptacle, and plug...

In your situation the best option would be to purchase a controller with a 4 prong plug... remove the plug, and run a new 4 conductor cable from your service panel all the way to the controller, and then to wire the new cable directly in, instead of wiring a new outlet and then plugging in the controller. You'll spend some money running a new 4 wire conductor, you'll save money not buying a receptacle, and you'll have a solid connection between the main panel and the new light controller.

I recommend 240v because it uses 2 hot legs (which is 180 degrees out of phase) this means it uses smaller gauge wire due to the lower amperage. which translates into less heat and cheaper cost.

MisterSosa said:

I recommend 240v because it uses 2 hot legs (which is 180 degrees out of phase) this means it uses smaller gauge wire due to the lower amperage. which translates into less heat and cheaper cost.

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It doesn't actually translate into less heat unless your conductors are undersized for the required load. Heat is only generated by circuit conductors if they are moving too much current. The ballast will produce the same amount of heat on 120 volts, or 240 volts.

The conductors would have to be grossly undersized or grossly overloaded to create enough heat that you would be spending money just on electrical losses. The ballasts will still have a much greater heat loss than any circuit conductors will.

From an operational cost standpoint, if your only motivation to move to 240 volts is that you believe your utility bill is going to have an even noticable reduction, you'd be in error. The load isn't changing, and heat losses from 120 volt vs 240 volt circuits is going to be insignificant.

Going from 120volts to 240 volts is more about adding capacity than savings.

u are not charged for volts but watts so no money savings