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Discussion Starter #1
Folowing up from a previous post...thought a new post would serve better...

Installing Direct-Wired waterers in horse barn (breaker to waterer directly)....
I want to install GFCI breakers, but I'm concerned about the distance with 1 waterer.
2 waterers will be about 75' from subpanel.
1 waterer will be about 350'
Do I need to install a second subpanel for the waterer 350' away?
What is the distance the GFCI breaker will correctly protect without false tripping/issues?
Thanks again!
 

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There is no exact distance for a GFCI breaker, but at 350' you might have a bigger problem with voltage drop.

What is the voltage and amperage of these circuits?
 

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The amps for each waterer is only 1.3 or 1.7
feed the 350' receptacle with a 20A breaker and #12 and you will be fine. just be aware that you will only be able to draw a few amps and not get excessive voltage drop. if you are looking to have, say, 10 amps available out there, you'll need to run a #8 at least.
 

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Distance does not create the need for a subpanel. Given the total current draw of about five amperes, a subpanel is still not mandatory. You could use a (weatherproof) junction box instead. Optionally you can add on-off switches wherever you wish.

For the distances you specified (700' to the furthest point), use 6 gauge from the main panel out 350' or so, to the first junction and unshared 10 gauge cables to the waterers themselves (12 gauge from waterer to junction if less than 200'), or use 8 gauge wire from the main panel throughout.

I don't know whether, in your situation, the long wire runs will cause funky behavior of a GFCI breaker at the main panel so I can't pass judgment on whether you should instead isntall in-line GFCI units near the various waterers or perhaps just one GFCI unit at the first junction.
 

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Discussion Starter #7 (Edited)
AllanJ....would love to eliminate the need for a subpanel....how would the junction box work??? I need to splice the 6 ga wire from the main panel (350' run) into the 3 separate waterers...? Would I use 3 junction boxes?

How would you install/mount the junction boxes? - they are in the middle of a horse field (3 separate fenced in areas)...?

Where would you install the in-line GFCIs? I would be running UF wire coming into the waterer from directly underneath it.
Would I install them at the junction box? - again, how to mount these outdoors?
Any recommendations on which type/brand to use?

Sorry for all of the details...just trying to get it right.
 

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AllanJ....would love to eliminate the need for a subpanel....how would the junction box work??? I need to splice the 6 ga wire from the main panel (350' run) into the 3 separate waterers...? Would I use 3 junction boxes?

How would you install/mount the junction boxes? - they are in the middle of a horse field (3 separate fenced in areas)...?

Where would you install the in-line GFCIs? I would be running UF wire coming into the waterer from directly underneath it.
Would I install them at the junction box? - again, how to mount these outdoors?
Any recommendations on which type/brand to use?

Sorry for all of the details...just trying to get it right.
Only one junction box is needed and it would go where you thought of putting the subpanel. This might have been at the nearest waterer.

A typical in-line GFCI unit fits in a box used to hold a light switch but the box should be a little larger than average, at least 3 inches deep. If you wanted to try one GFCI for all three waterers then you would put it in the line from the panel just before the junction box. If you wanted a separate GFCI unit for each waterer then you would put each just under its waterer.
 

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that 350' run is most likely going to trip a gfci breaker at the drop of a hat, the dead front gfci's is a far more cost effective and better way to do it. Also if it does trip you don't have to walk all the way out, see it's tripped, walk all the way back and then all the way out again lol. You'll need pvc watertight boxes and weatherproof receptacle covers for them(a dead front gfci looks just like a regular one but with no plugs). Might be cheaper just to buy the actual gfci plug package that comes in an outdoor box, you have 6 gauge going out so voltage drop shouldn't be an issue and you'll also have the option to plug something in there if you want. You would just tie the waterers into the load side of the gfci. Being as the two runs are so far apart i would suggest putting in a gfci at each location. Just make sure you tap off the incoming to go to each gfci, as in don't put a gfci on and then come off the load side to another gfci. There's 100 different way to do it, it all boils down to cost and convenience for you
 

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I agree, the junction box scenario would work just fine. I'd place a box near the first waterer then run GFCI protected power to the waterer. From the JB, I'd then run out to the far waterer and do the same. I'd only have the GFCI devices at the waterers rather than try to get one device to protect the whole thing.

The biggest issue here is the voltage drop. As long as you're covered there, it's just like wiring a large room.
 

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Discussion Starter #11
Thanks for all of the advice...

Can I get away with 8 or 10 gauge UF wire to the Junction Box (350')? or do I need 6 gauge?

At the junction box, can I splice the incoming wire (6 or 8 gauge) into 3 separate runs out to each waterer? I would then have an outdoor box with the gfci or dead front gfci near the waterer.

Also, UF wire into the junction box & gfci is OK correct? and can any size wire (8, 10 gauge) go into a 15 or 20 amp GFCI???? To prevent voltage drop, I will have to run more than the standard 12 gauge obviously....just making sure it's ok to put something like 8 gauge wire into a GFCI?

Thanks again! you guys have been helpful.
 

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Generally, long distance runs of wire connected to a GFCI breaker can cause nuisance tripping. This is due to normal induction characteristics of AC circuits.

Using a stand-alone GFCI device near the point of use would probably offer superior results IMO.
 

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Is there another way to skin this? Maybe use 24VAC to the float switch in the waterers and run that back to the house and use a relay (http://www.functionaldevices.com/building-automation/display.php?model=RIB01BDC) to switch a solenoid water valve near the house instead of at the paddock. Then just run poly pipe after the water value out to the tanks/troughs? This way you use cheaper low voltage wire for the 350' portion. You have to run the pipe anyway just put the valve at the start instead of the end.

Better still may some type of RF switch where you use float switch to trigger the transmitter and then go wireless back to the solenoid valve.

http://www.functionaldevices.com/building-automation/wireless.php
 

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Because of the 700 foot distance to the furthest waterer and the fact that two other waterers are sharing the first half of that distance, you will need either 8 gauge wire all the way, or 6 gauge for the first half, and 10 gauge for the second half of that run for the 1.7 amp (200 watt) waterers as-is.

Twelve or fourteen gauge pigtails between the 6 or 8 gauge line and a GFCI unit (to fit under the terminal screws), and even a 14 gauge pigtail between the line entering the panel and its breaker will not introduce or re-introduce voltage drop problems.

If you can use float switches only in the field and control the water flow back at the barn using contactors and valves, get contactors whose control runs on 120 volts, not 12 or 24. If the contactor control (its coil) needs 30 watts @ 120 volts, (3 contactors use 90 watts) you can run 14 gauge wire throughout. (You need 4 conductors, three control lines and one common line, arriving back at the barn.) Now if you can get valves that operate on just 30 watts then you won't need contactors.

Using low voltage will result in much worse voltage drop problems. For a given number of amperes and a given piece of wire, the same number of volts, not the same percentage of volts, is lost. Also consider that, for the same number of needed watts, lower voltage means higher amperage.
 

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One other thing to consider when installing the wire - can you ever, in your wildest dreams, see yourself looking at that power outlet 700' from the house and say to yourself, "I can use that to plug in my circular saw!" or in any way want to use it for any other purpose than to feed the waterers?

So you'll need to decide if you want to plan for the future (install larger gauge wire now) or commit to this power run as being dedicated to feeding only the existing waterers and never anything more.
 

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You would need 2 gauge wire the whole way to give you 15 amps at 120 volts 700 feet away (3-1/2% voltage drop).

While you might be thinking of tolerating a little more voltage drop, say, 5% with 4 gauge wire the whole way, keep in mind that there may be additional voltage drop from the utility pole to the house and from the house to the barn, depending on other barn usage such as cow milkers and chicken incubators. Adding in the voltage drop from barn to the fields we are dealing with here and any voltage drop in an orange extension cord you might bring out there and need, the total voltage drop may degrade the operation of power tools.
 

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I must have missed the part where he said it was 700 feet, it says 350 feet in the original post. The number 6 is plenty big enough for that. To be safe you may want to run number 10 out from the first waterer to the second.

As for the low voltage thing there's no way that will work. You would need a huge cable to carry 24v that far. Remember voltage drop is calculated as a percentage so it's a lot easier to drop 5% off 24v's than it is to drop it off 110v.
 

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The topic was first started here:
http://www.diychatroom.com/f18/outdoor-subpanel-350-feet-away-barn-141333/

The OP started by discussing a proposed 350' trunk line (2 conductor 120 volt) from a barn subpanel to somewhere in the middle of a field for a proposed sub-subpanel. Then he corrected himself to say there was a second 350' from the sub-subpanel to yet further off in the middle of the field. This latter segment is the latest subject being discussed.

We are currently concluding that a junction box can be used instead of the sub-subpanel out in the field.

The longest run to be installed is thus 700' one way or 1400' round trip. From the halfway point two other branches go off in different directions. You need to consider the round trip when figuring voltage drop.

Let's say for a given section of wire (it has resistance of X ohms) there is a 1 volt voltage drop at 120 volts (slightly less than 1%) when 1 ampere is flowing. If we used 12 volts for that wire and 1 amp was flowing, we would also get a 1 volt voltage drop which is about 8%. Now for 1 ampere at 120 volts we need 10 amperes at 12 volts to get the same number of watts. Ten amperes going down that same wire would result in losing 10 volts to voltage drop. Losing 10 out of 12 volts is losing 83 percent.
 
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