I own 100 acre ranch in Texas and need to provide an electric water pump at a pond.
The distance between the pond / pump location and my electrical panel is 640 feet.
The pump will serve needs for 1 -2 years, at which time we will have a barn / shop and perminent electrical power near the pond / pump.
Being that it is temporary, I would like to provide electrical wire at as low a cost as possible, and will bury the wire (direct) or in conduit. It has been suggested to use wire in conduit on the open ranch to offset underground varmit problems. One of our electricains suggest #8 wire, another suggest #6, and a “wiring tech specialist” at an internet distributor says I can use #10 or even #12.
The specs for the pump, which be the only electrical draw on the circuit, are as follows:
Volts 110
Amps 5.4
Max Surge Amps 30
Continious Amps 6.1
The circuit will not be sub-merged or wet. The circuit will provide for anything other that the pump.
I need help with the right wire size the wire for the application?
Replies
no answer but-
Nice to see you're still breathing!
A Great Place for Information, Comraderie, and a Sucker Punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
no answer but-
Nice to see you're still breathing!
Thanks Calvin.
240Vac on 12 AWG or even 14 AWG. 2:1 XFMR on load side of the control switch, then 110/120 to the pump.
I run a 3/4 HP compressor in a shed 500 ft away and the last 200 ft is only 14 AWG.
BTW, for just 2 years, if DIY and you do not need to get a permit, I'd even direct bury plain ol' romex type cable 14 AWG (except for varmit problems, severity of which I know nothing). Put a 50 uF or so 240 AC rated cap on the xfmr secondary to correct for PF and lower the current draw somewhat. Conduit and 2 strands of 12AWG may be cheaper than UF 14 AWG evenif you need to pass code.
Edit - or skip the xfmr and get a 240 Vac motor?? May be cheaper then the xfmr if you dont have any laying around.
Edited 9/8/2009 11:23 am ET by junkhound
Junkhound,
The pond is / will be about 4 acres. Currently we have an excavator stationed at the pond. The excavator owner has 4 dumps trucks and 2 dump rigs. He excavates and loads to service his dirt clients, and we also use his service to build up road beds in the upcoming residential development on the property. Once we install the circuit and the electric pump is functional, we will pump the bulk of rain water accumulation in the pond with a tractor driven PTO water pump, set the electric pump at the low point with float switch to automatically maintain a low or dry water level so that progress can continue at or after rain events.
I am a builder, but do not mind asying that I am not so well versed in tech details, so I will ask:
"2:1 XFMR on load side of the control switch, (then 110/120 to the pump)."
What does this mean?
This is DIY, and rural without permit.
"Put a 50 UF (underground feeder) or so 240 AC rated cap on the xfmr secondary to correct for PF and lower the current draw somewhat."
What does this mean, and why do you suggest this scenario?
skip the xfmr and get a 240 Vac motor
Again, I am a little lost within this suggestion. .
There are a number of online voltage drop calculators, this is the one I usually use: http://www.csgnetwork.com/voltagedropcalc.html With 120vac pump running at 5.4 amps, over a distance of 640 feet it says #6 wire - you want to keep the voltage drop around 3% or less. This is where a 240vac pump would have an advantage, as the voltage drop will be less over that distance and you would be able to use smaller wire. edit: you could probably get away with using the #8 wire suggested above, but the voltage drop will be a little higher than recommended.
If you can only get a 120vac pump, you could possibly run a 240vac circuit out to the pond and then use a transformer to step the voltage down to 120vac when you get there - this would have the same effect of reducing the wire size, but you'd need to find a suitable transformer. Art probably has a shed full of them, but for the average joe it may be more expensive than just running the bigger wire in the first place and keeping everything at 120vac.
Edited 9/8/2009 1:45 pm by Stuart
If you're going with a transformer, might as well step it up to 440V and reduce voltage drop even further.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
I would have a tendency to use 20A breaker, #8 THWN wire, in buried 3/4" or 1" PVC conduit with a couple of straight through pull boxes included in the run.
Suck a light messenger string through the conduit with your shop vac (mason's twine works great); pull heavier cord with string; pull wires with the cord.
Before making any wire purchases, I would call the pump manufacturer and inquire as to how fussy your pump is to voltage drop. 10% ok?, 5%?, 3%
Below is raw formula - what I cannot remember is whether with AC you use a one way wire length or round trip, i.e., 640' or 1280'. DC is round trip.
V = I x R
V = voltage drop
I = current (amps), 6.1 in your case.
R = Ohms resistance of the wire as shown below
#6 awg = .403 ohms per 1000'
#8 awg = .641 ohms per 1K'
#10 awg = 1.02 ohms per 1K'
#12 awg = 1.62 ohms per 1K'
Others will chime in.
Jim
Edited 9/8/2009 11:36 am ET by JTC1
Just to add a comment, if the building is going to be in the path of the electrical line, how do you plan on powering it? Rather than pay for a line now, and a line later, put in big enough for the building, and save the cost and time of trenching a line now, and a line later.
Thanks for your suggestive question(s)?
We are planning a 60 x 80 office / shop at the pond area. To power the new building, and other future improvements (we may build cottage homes around a portion of the pond), the power company will be installing electrical power line down the property line.
I won't have power until the building is complete and electrical panel functional. In the meantime, I will need power to the pump for dry conditions in order to continue excavations.
At the point where the new building is functional, the pump location will be about 250' away, and will become a pumped bog - bio filter / rock water fall area.
Value Trivia: Anyone ever heard of adding sheetrock scraps to a pond? One of our custom home clients who owns 1200 acreas asked to keep the sheetrock scraps. He placed the scraps from the 4000 SF home in a silty brown pond. In a couple of weeks the water and floating sediment cleared and the pond turned a somewhat clear greenish blue. Note that the pond was 1/2 acre + or - and the SR scrap pile was about about 4 yards.
The #8 looks about like the smallest you can use without getting significantly over 5% V/D. If your input voltage is high (123 or so) you might get away with #10 but you will be dropping around 10v.
If you can re-tap that motor for 240v you would be a lot better off.
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_21891_21891
The pump. Great user reviews.
You have a couple of problems and challenges to consider.
The first is 'voltage drop.' Simply put, the more current you draw through a wire, the more voltage you lose. Where this can be critical to you is that, if the pump needs 30 amps to start (not unreasonable for a 5 amp rated (FLA) motor, and your voltage drops too much, you won't have the power you need for that instant to get the pump going.
Two factors affect the amount of voltage drop; the diameter and the length of the wire. Since your run is well over 100 ft (the distance the tables are based upon), and your starting current is often 6x the running current, you need to look at the ampacity tables as more of a suggestion, not a prescription.
As cheap as possible? How many times do you want to replace burnt out pumps and inadequate wire? Take the time to do it right.
If you run direct burial wire, varmits aside, you need to bury it deeper than you would have to bury pipe. Pipe you could even - conceivably - run right on the surface. Otherwise, you're looking at 12" minimum for pipe and 18" for UF cable.
Anything underground is in a 'wet' location, by definition. Most wire insulations will quickly break down when in direct contact with the earth - so if you direct bury a cable, don't even think of using anything but UF cable.
"Temporary" is defined by code as 90 days or less - a couple years down the road doesn't qualify.
Yours is one of the rare situations where I consider the use of UF cable to be reasonable; pulling 600+ ft. of wire in even a large pipe can be a challenge. I think the parts house guy is being optomistic; I'd look at #8 wires with a #10 ground as the minimums.
If you decide to run pipe, I would reccomend 1" PVC (minimum) buried 24" down, with a pull box / handhole every 90 ft. Use 'sweeps' to have the pipe enter the handholes from below.
Thanks. Good advise.
My first (off the top of my head) inclination:
3 runs # 8 copper stranded / 2 hot / 1 neutral / 1" conduit @ 24" deep / 1 # 10 ground
40 AMP double pole breaker / run to sub-panel / split to 1 - 30 amp singe pole circuit for pump and 1 - 15 amp aux circuit
What do you think?
I have learned the biblical precept that in an abundance of counsel there is wisdom is true. So, I ask questions of all resources as possible.
The soils are great for building. I will be due $15.00 ($1.00 per yard) per load for 175 loads from the aforementioned excavator / dirt man when we dry the pond, and the potential for many more loads. Maybe that is how I can explain the expense to my wife, who wants a new house this spring. : - )
>>What do you think? <<
That would work.
I would consider GFCI breakers and ground rods at the weather-tight subpanel.
Might just split into two 20A lines - 1 for pump, 1 for auxiliary outlet.
JimNever underestimate the value of a sharp pencil or good light.
I am not too familiar with solar power, but does anyone know if there a small solar system capable of running this pump?
Flow (GPH)
3,810
Volts
110
Amps
5.4
Max. Total Head (ft.)
39.5
Impeller Shaft
Rubber
Seals
Silicon Carbide-Faced Mechanical
Surge Amperage: 30.5
Continious Amperage 6.1
Have you checked with the power company to see if they would just run a temporary power pole there with another meter? Might turn out to be cheaper. I know my rural electric membership corporation just charges a $10 per month minimum for a drop with another meter for stuff like electric gate openers, outbuildings etc. If you use more than $10 worth of electricity on it you don't even notice. The power company pays all the cost of poles and wire and putting it there. You basically just rent it. An electrician can put a circuit breaker panel on it to run pumps, saws, air compressors and whatever you need to build that future building.
Beachton beat me to it: Power pole to near the location, then middling-standard SE drop to pump.
Looks like Kyocera makes a PV panel that would get you the running amps (probably ought to have a grid connection for the start). Which makes another reason to get a pole, it would give you a handy place to install the PV. You need an inverter and a battery, box for the PV, which could all go in the pump shed.
All of which has a detached, academic feel to it, what with most of the stock tanks around here most of dry, and really only visible for being green from the last of the moisture.
Drywall scraps is old ranch logic. As a guess the gypsum changes the ph which will cure the water of algae and the like. Do not know what that does to any fish in the tank. If I run into an aquaculture typ or icthyologist, I'll ask.Occupational hazard of my occupation not being around (sorry Bubba)
>>Drywall scraps is old ranch logic. <<<
Minor hijack.
One year I lost a sizable percentage of my tomato crop to "blossom end rot". Tomatoes would fill out, start to get red, and then turn black and start rotting at the blossom end of the fruit.
Someone told me this was due to a lack of calcium in the soil.
The next spring I tilled new drywall scraps, paper and all, into the tomato bed. About 50% coverage with 1/2" regular drywall, lots of tilling.
No blossom end rot for 3 years.
Now back to our regularly scheduled program......
JimNever underestimate the value of a sharp pencil or good light.
Hijack IIHere in South Georgia, we routinely apply "land plaster" i.e. gypsum, to our peanut crop. Toughens the hull, helps the pea fill out the shell. Locally, peanuts and pecans are our big money crops. It's not unusual to yield 2 1/2 tons of peanuts per acre.Back to our regularly scheduled programming . . .Greg
good observation, but:
Drops are limited to 60'. It is 640' from the house house to pump location, 850' down the property line from power lines to a postion parallel with the pump location. The power company will eventually set poles at at 50' from the property line and another every 400 feet. The cost for 850" (we may continue down the 2500' property line) of service along the property line is cheap at $1,400.00 installed.
Setting poles down the property line is the ultimate plan, but working with Center Point Energy, the infra-structure provider in this area, is like dealing with a 400 pound gorilla. They do what they want when they want. Some things are in progress, but it took two weeks to get an appointment with a Center Point engineer, and it has been several weeks, phone calls and emails to get him to send the requirements / check off list. At submission of all docs to include easement rights, it will take another 6-8 weeks for approval and scheduling and another 2-4 weeks to install. Bummer.
If I can make a decision on this wire thing, we could be excavating at the end of next week. Aside from digging a pond and improving the property, I will build the foundation pad for the shop / office, have a new home to start that needs 65 loads for the foundation pad and my excavator / hauler has a 175 load project on hold waiting for a dry pit.
All of the pits around here are wet. My plan for rain water accumulation maintenance will set us free to make money. Note that my excavator / hauler excavates and hauls within 15 miles for me and charges $70.00. The going rate for a load of select foundation fill from other local pits is $125.00 and up.
Edited 9/8/2009 6:50 pm ET by txlandlord
A transformer, really? Just to regulate voltage drop on a 5.4A water pump?