qtla9111
Monterrey, Mexico
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Until we get our new place set up and our solar in place we are running a line to the rv pad. Using the calculator below it says we need #3 cable and I just want to verify it to make sure I am doing this right. 30 amp service for 250 feet.
Wire Size Calculator
Thanks in advance.
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Tenn Stud
Northeast, TN
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Joined: 11/16/2004
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minimum wire size in copper wire with thhn ins should be #4
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Hurricaner
Hurricane Utah
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#4 will be fine as long as you are coming off the main panel as it is less than a 5% drop. If this is just temporary, you might get away with a # 10 if you keep the use under 15 amps.
Sam
Sam & Kari
Hurricane, Utah
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Bob Landry
Austin, texas
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I did the numbers in the calculator and it came up with #2 cable. That's not out of line for a run of 250 feet and that's going to get very expensive. I doubt you will find #2 3-conductor. BTW, percentage of voltage drop only applies if you are dealing with DC, not AC. Wire for AC is sized by the load and distance of the wire run..
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dontay
Mims, Florida
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Good grief!! The wire gages quoted above are over the top even for the internet. An electrical contractor ran our 240V service from the house 220' to the workshop panel with #4 cable. It has 60 amp breakers at the house and is used to power our well, MH with 50 amp service, washer, dryer, small water heater, small freezer, as well as my shop tools. Obviously, we do not run all this stuff at once (like my wife does laundry early before A/C's have to be turned on, etc.)
From the w/s I ran 110' of #6 wire for the 50 amp service in the MH garage. Sitting in the garage my voltmeters show 115V on each leg when the A/C's are running. If the electric MH water heater cuts on the voltage drops by 5 volts on that leg.
Because we don't like living in the garage we park on the apron and plug in through a 35' 50 amp extention cord. That is in addition to the 25' cord on the MH. (both #6) When doing that the voltage shows 110V but turning the microwave on caused the voltage on that leg to drop to 105 so we shut off the front A/C if the uwave is to be used.
I will surely be glad when the house is finished but electricity is not a concern.
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j2catfish
Newport, NC, U.S.of.A.
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Bob Landry wrote:I did the numbers in the calculator and it came up with #2 cable. That's not out of line for a run of 250 feet and that's going to get very expensive. I doubt you will find #2 3-conductor. BTW, percentage of voltage drop only applies if you are dealing with DC, not AC. Wire for AC is sized by the load and distance of the wire run..
Please provide us dummies with your reference for the above statement. Thanks.
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Hurricaner
Hurricane Utah
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Quote:BTW, percentage of voltage drop only applies if you are dealing with DC, not AC. Wire for AC is sized by the load and distance of the wire run..
The NEC recommends no more than 5% voltage drop at the outlet. Some city's require this. I have never heard of a distance requirement by the NEC only percent voltage drop and it is a recommendation not a requirement...that is one of the reasons you have low voltage in RV parks.
Sam
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qtla9111
Monterrey, Mexico
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Maybe I am the dummy here. I put in the following factors; 120V, copper wire, single phase, 30 amp, 250 ft. That is how I got the results.
I guess I should say this is a 40ft 2 bedroom Keystone Hornet with one 13.5 a/c unit and microwave. Refrigerator, water heater, and heat on LP.
Thanks for all the replies. I may learn something here.
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Allen Schultz
Divide, Colorado USA
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What you are going to get is a large selection of opinions with a couple people offering you solid advice. The problem is, you won't be able to tell them apart! I would be inclined to follow the wire calculator, or ask an electrician.
You didn't mention how long you would be requiring the temporary service, but if it isn't too long, you might consider putting the money into a generator instead of copper wire. In the long run, you will end up with a useful appliance instead of a coil of used wire. You could even run relatively inexpensive 12 gauge to operate the lights and television, and use the generator for air conditioning.
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MURDIG
Marshalltown Iowa USA
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1. you don't say how you are going to get this 250'
a. underground direct buried- you probably won't find
#3 copper and if you did it would be extremely expensive.
b. PVC conduit 1" in size for #3 this would be more permanent.
c. overhead
2. what kind of load are you figuring, just maintenance power or full load
3. these are all variables in sizing wire, best bet is to consult a licensed electrician.
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