Art Project / Road Light selectrical advice

[woodlandfarms]

So this one is a bit more complex....

I plan on making some LED lit scultpures along our driveway. Could be real cool or a real failure.

At the end I could potentially be 700 feet from a power source.

The sculpture will be wrapped in LED Bulbs, Lets say 50 ft of ribbon (No Clue Estimate) The ribbon consumes on the high end 1 watt per foot, so each sculpture is 50 watts.

Now comes the tough part that is beyond my scope. The power supplies are rated from 85 volts to 240V.

I could do the following. Run 110 down the hill, knowing full well I am loosing power as i go, I could Run 220, which seems to have provide me a bit more amperage for the same wire width, or I could attach DC with high amperage to power the line.

The line, I don't want this project to spin out financially. 700 Feet of direct bury 10 guage at a buck a foot is painful. There is 250ft of 12-2 DB Low Volatage that is $80 a spool.

Anyway, just don't know enough on length runs to figure out how best to do this. I am thinking 6 sculpture max. And it may be on 2 seperate lines. (left and right side of road)

 

[Mendonsy]

Have you considered solar panels for power? They are available for about $1.50 per watt.

 

[woodlandfarms]

Solar won't work. We are on the darkside of the mountain.

 

[chim]

Without more info on the total load, the voltage drop can only be guessed. With such a long distance the drop can be significant. With a normal circuit where you would want to use loads like tools it would be a concern. The LED's make a difference because the driver isn't very fussy about the input voltage.

If the load works out to be light enough I'd start with a one-piece 12/2 UF for the run, or install handholes for splices so you can access them in case of failure. Underground splices can last indefinitely, but I'd be concerned. Especially since you aren't mentioning any conduit the backfill should be free of rocks/stones/etc.

HD has 1000' reels od 12/2 UF on their site for $476. Since this is a circuit with a single purpose and won't be for general usage, I'd calculate the voltage drop and likely power it with 240V. The power supplies I saw for this application on the "1000bulbs.com" illustration show a 120V plug. I'd change the plug or cut it off and wire it direct (and mark it well) to avoid having a surprise for someone in the future.

 

[EddieWalker]

I think having a couple of outlets along the road with enough power to handle whatever you build, and might want to add later on should be the way to go on this. You said 800 feet. I would first decide where you want your outlets and decide how far apart they need to be. Then I would do this in three runs with a separate 20 amp breaker for each run. First run would be 300 feet of 12/2 wire. Second run would be 600 feet with 10/2 wire and the outlets would start after the first run. Last run would be 800 feet of 10/2 and have outlets on the final 200 feet. I would put all the wire in the same trench, but use separate conduit for each run.

Eddie

 

[woodlandfarms]

Great ideas. So what I am hearing is keep the voltage in the 120/240 with transformers at each sculpture and do not go with a high amp 5 volt dc power supply as a master source.

 

[mjw357]

Run 240VAC on 12/2 and call it a day. You said the power supplies are rated from 85v to 240v, so I am guessing they are some type of switching power supply. The output to the LED strip lights should be the same no matter the current draw/voltage drop as long as it stays above 85v.

 

[aczlan]

Great ideas. So what I am hearing is keep the voltage in the 120/240 with transformers at each sculpture and do not go with a high amp 5 volt dc power supply as a master source.

High amp 5VDC would be the last thing I would use.
For longer runs, higher voltages cause less power loss and require smaller wires. As such, 240VAC with step down transformers at each pole would (IMO) be the best option.

Aaron Z

 

[Mendonsy]

If you run 12/3 instead of 12/2 that would allow you to put in a few 120 volt outlets and still run your lights from 240. Those might come in handy some day??

 

[woodlandfarms]

Thanks guys. I just remembered Ohms Law and realized that the DC Push on the lines would be stupid. 240 it is.

Mendonsy, at that distance I would be lucky to get any useable juice at 800 feet to power anything but maybe a battery charger for an automatic gate (you see where I am going with this, don't ya?)

 

[Cord]

Try plugging your data in this calculator: Voltage Drop Calculator

When I plug in a 15a load with 220v power at 700' distance I come up with a #4 copper conductor. #2 if you want aluminum. 3/0 at 110v with aluminum. The getcha is that most domestic three prong outlets are not 110v. Make sure you use the correct 220v outlet with the horizontal tang.

With #8 copper (no option for #10) and a 15a load at 110v you can only go about 160' before the voltage drop exceeds 3%.

Summary: Long runs suck with low voltage.

 

[aczlan]

Thanks guys. I just remembered Ohms Law and realized that the DC Push on the lines would be stupid. 240 it is.
Mendonsy, at that distance I would be lucky to get any useable juice at 800 feet to power anything but maybe a battery charger for an automatic gate (you see where I am going with this, don't ya?)

Per Voltage Drop Calculator starting with 240VAC on 12/2 wire with stepdown transformers to your lights and a 240v to 120v stepdown transformer for your gate (although, if using a 12v powered gate, a 240VAC to 12VDC charger might be more efficient) would give you 2 amps at 240VAC or 4 amps at 120VAC.
A 10 gauge wire would bump the available power to 4.5 amps at 240VAC.

Aaron Z

 

[dave1949]

Phase Converters & Step-Up Transformers - Phase Converter Information

Interesting thread. I don't know if step-up/down transformers are an option price-wise, but they would get the power moved without a lot of line loss.

 

[woodlandfarms]

So here was an interesting question posed to me. A friend has an estate. The road is a good 1000 feet long and there are lights up and down the road. I am assuming that either underground their is a massively thick cable or some sort of transformer stepping 440 down to 110 hidden in the trees. Anyone have first hand experience with lighting long driveways?


But back to my project.... I might have 4 working amps avail on the run. Each display is pulling lets go high and say 100 watts. I need 600 watts. Do I base my needs on the transformer and 12 volts or the 220 running down the hill. With 12 volts I am at 50 amps. Guess I have my answer already.. With 220 I need an amp...

 

[aczlan]

So here was an interesting question posed to me. A friend has an estate. The road is a good 1000 feet long and there are lights up and down the road. I am assuming that either underground their is a massively thick cable or some sort of transformer stepping 440 down to 110 hidden in the trees. Anyone have first hand experience with lighting long driveways?

Probably the voltage is stepped up and then down...

But back to my project.... I might have 4 working amps avail on the run. Each display is pulling lets go high and say 100 watts. I need 600 watts. Do I base my needs on the transformer and 12 volts or the 220 running down the hill. With 12 volts I am at 50 amps. Guess I have my answer already.. With 220 I need an amp...

100 watts at 12v is 8.3 amps. That's a lot of light. A 9004 high beam is only 65 watts...

Aaron Z

 

[Mendonsy]

Thanks guys. I just remembered Ohms Law and realized that the DC Push on the lines would be stupid. 240 it is.

Mendonsy, at that distance I would be lucky to get any useable juice at 800 feet to power anything but maybe a battery charger for an automatic gate (you see where I am going with this, don't ya?)

Yes. I just thought having an outlet or two nearby for some power tools might prove useful someday.

Here is a link that might get you better prices on underground cable. They had 12/3 UF-B for $680 for a 1000' roll.
Electrical Wire, Welding Cable, Romex, Hook Up Wire - WesBell Electronics

 

[RobertBrown]

Make your sculptures from clay? The amp draw is considerably less....