A long distance wiring question

[mjw357]

Depends on the motor in question. I've tried to use my air compressor on 200' of extension cord from the house. The motor will run noticeable slow and then will trip the breaker that's on the compressor. As voltage drops, current rises.

 

[RyGuy24]

The issue you get with starting motors is the inrush current which can be as high as 6x the motor nameplate current. This compounded with voltage drop over long runs of undersized wire can burn out motors. A wire rated at 20amps drawing 20amps gives you "x" voltage drop (don't have my code book near) but I you're starting a motor under load an that same wire has say 60amps going through it you have approx "x" voltage drop times 3 so you can see the problem compounds. The reason lights aren't affected as bad is because there is no inrush current to start them. Also power tools normally have no load or not much so they start easy which reduces the inrush current. You will notice they don't have nearly as much 'torque' when on a long undersized cord, this is because of the voltage drop increasing as the load goes up. Air compressors are a great example of this. When starting there is no pressure in the cylinder but it builds pressure quickly so if it doesn't get up to running speed of the motor (which means full hp which the current drops when it reachs synchronous or slip speed) before the pressure builds up you will have a compressor which will humm and do nothing but burn its motor out unless youre lucky and the overload trips or you turn it off.

 

[Joe H]

If you are running a breaker box at the end of the wires, that is what I would do, then you have the two hots and one neutral and the ground all connected at that panel. With both hots to one side of the box. I would drive in a separate ground rod, or as is required hear a plate buried 2 ft in the ground. The neutral and grounds in all breaker boxes are both connected to the body of the panel. Then run your equipment off of that.
Just a thought!

The neutral is NOT bonded to ground in a sub panel.

Joe H

 

[hr3]

So here is the dilemma. I found I have 12.3 running 250 ft and not 10.3 as it should be.

To create a 110 circuit, can I double the hot side up without doubling the neutral? Meaning can I hook the red and black to the hot leg of the breaker (2 12guage wires) but keep the neutral ( white ) as a single 12 gauge?

If yes, will this improve my voltage drop problem?

One thing nobody has asked yet is what is your load,,??? What are you trying to run at that distance,,

 

[woodlandfarms]

So here is my setup.

I have an abandoned well 250 ft from my house. In the breaker box the wire is 10 guage. But at the outlet it is 12 guage. I set it up so that i had two 110 legs abandoning the 220. The install was done on the cheap I guess that is why there is 12 guage for a well pump. At the relay box that activated the old well pump is where the switch in guage is made.

I ran my Sawzall the other day and it ran but slow. I ran an air compressor earlier and it ran just fine.

The heaviest load i forsee is either a power tool or the Inlaws camper which has a mini fridge.

Carl

 

[grsthegreat]

What happens to the electric motor?

I ran 12/2 eight hundred feet to my front gate and installled some lights on either side of it on a 20 amp circut. I also put in an outlet that I use for power tools when I'm doing something out there. When I was installing the cultured stone on my block, I ran my 14 inch chop saw to cut the stone. When I was installing the block, I ran my cement mixer. I've used power drills and even an electric weed eater with a one hundred foot extension cord.

Everything worked fine and all of those tools are still working many years later.

I actually have 124 volts on each leg at my panel. Does that mean the extra 14 volts will wreck havoc on my motors? or is that only when it's under 110 volts? I really don't worry too much about voltage, just amps.


Eddie

well im not sure what kind of loads you have on a 800 foot run, or even how any motor can run with an 800 foot extension cord (so to speak). If i was to try and run my hole hog on 200-300 foot #12 extension cord, it doesnt run very well...if at all.

Ohm's law states that as voltage decreases amperage has to increase to compensate. So as voltage drops on a long run (voltage under load) ..the amperage has to increase to compensate for it. Now if the wire ISN'T thick enuf to allow for this increase in amperage, heat is produced. Same with a motor. If it cant get enuf power to operate properly, it will draw more amperage...thus heat up. I have actually burnt out hole hawgs over the years using too long of an extensi9on cord that wasn't thick enuf.

So im really not sure HOW you can operate cut off saws at 800 feet. never seen that accomplished ever. But all i can say is the reading at the end of the run (125 volts) is a non loaded reading. id be interested in seeing a voltage and an amp reading while a saw or drill was being used.

Also im confused by the statement that you ran 12/2 but have 124 volts on each side. Is this the voltage between the neutral and the hot?. Theres no way 12/2 can give you 2 separate 120 volt circuits? am i missing something

thank you

 

[hr3]

So here is my setup.

I have an abandoned well 250 ft from my house. In the breaker box the wire is 10 guage. But at the outlet it is 12 guage. I set it up so that i had two 110 legs abandoning the 220. The install was done on the cheap I guess that is why there is 12 guage for a well pump. At the relay box that activated the old well pump is where the switch in guage is made.

I ran my Sawzall the other day and it ran but slow. I ran an air compressor earlier and it ran just fine.

The heaviest load i forsee is either a power tool or the Inlaws camper which has a mini fridge.

Carl

Where does it change from #10 to #12 wire and how many wires do you have..?? Do you have a voltage meter of any kind??

I know lots of questions but in order to answer any question correctly one needs all the details of the question and situation..

 

[EE_Bota]

The issue you get with starting motors is the inrush current which can be as high as 6x the motor nameplate current. This compounded with voltage drop over long runs of undersized wire can burn out motors. A wire rated at 20amps drawing 20amps gives you "x" voltage drop (don't have my code book near) but I you're starting a motor under load an that same wire has say 60amps going through it you have approx "x" voltage drop times 3 so you can see the problem compounds. The reason lights aren't affected as bad is because there is no inrush current to start them. Also power tools normally have no load or not much so they start easy which reduces the inrush current. You will notice they don't have nearly as much 'torque' when on a long undersized cord, this is because of the voltage drop increasing as the load goes up. Air compressors are a great example of this. When starting there is no pressure in the cylinder but it builds pressure quickly so if it doesn't get up to running speed of the motor (which means full hp which the current drops when it reachs synchronous or slip speed) before the pressure builds up you will have a compressor which will humm and do nothing but burn its motor out unless youre lucky and the overload trips or you turn it off.

Edit:
I wrote stuff about a light being a dead short or an instant, and then current decay due to temperature rise, and then I decided that I am not nearly as confident in what I am saying as I am confident it really doesn't matter. So I think what you said is pretty good, though I may differ in some minor points for some lights.

 

[woodlandfarms]

Where does it change from #10 to #12 wire and how many wires do you have..?? Do you have a voltage meter of any kind??

I know lots of questions but in order to answer any question correctly one needs all the details of the question and situation..

10 feet from the meter box is the change over. Where the old relay was. I am wired to code (I believe) with 4 wires (Hot Hot Nuetral Ground) coming out of my box to the 12 guage running to the outlets (old pump)

I not only have a voltage meter but I also have that amp meter that plugs into the outlet (cannot remember the name at the moment). I will give it a go once it stops raining, taking a high amp tool down to see what happens when it all gets turned on.

 

[EddieWalker]

Also im confused by the statement that you ran 12/2 but have 124 volts on each side. Is this the voltage between the neutral and the hot?. Theres no way 12/2 can give you 2 separate 120 volt circuits? am i missing something

thank you

Not at both sides. At the house I have 124 volts when I put a meter on an outlet. I never put a meter on anything out at the gate.

I've run my cement mixer all day long, for quite a few days out there when I built the block for my sign and my gates. I used my chop saw to cut my stone while the cement mixer was running, all on the same wire.

After I was done, I installed some lights and they go on every night at dark. I use LED bulbs, so I'm not using very much power.

Eddie