# Running a long length of 110v wire underground



## leslyons

I am putting in an 110VAC electric sliding entry gate system (which converts to 24VDC with battery backup) for my 16 ft ranch gate at the front of my property. The two companies who have bid on the job have told me to plan on about 9-10 amps draw to be on the safe side. I also want to allow for a couple of low wattage post lights on each of the gate posts, and to allow for later expansion with a possible telephone entry system and a closed circuit camera above the gate. Of course the camera, lights and telephone entry are very low electrical draws, but I want to ensure I size my wire properly for the future. 

From the 100 amp panel it is 333 ft to the front of the property, and Iâve already got an empty 1â PVC conduit buried and ready for the wire to be pulled. From that point at the front of the property itâs another 60 ft over to the far edge of the gate, where the electrical gate operator will be.
One guy told me to run 10 gauge (2 conductor plus ground), and the other guy said to run 8 gauge to be safe. Based on the cost of wire today, I might have to take out a second mortgage!!! 

Question: Could I put in a small subpanel box at 250 ft, which is basically just a junction box to allow me to run a heavier gauge wire for the first 250 ft, then step it down from the sub panel forward to the gate â perhaps run 8 gauge from the panel to the subpanel, then run 10 gauge from there to the gate. That way I could buy a 250 ft roll of each. All the âcalculatorsâ are confusing and seem to WAY over-estimate the size wire needed. And should I use UF direct burial inside the PVC, or since it will be in PVC could I run Romex NM-B or should I pull three separate wires rated for inside use (cheaper) or direct burial (THHN, I think)? Iâm trying to get by as inexpensively (not cheaply!) as possible, yet still have plenty of voltage and not violate standard codes. Any help would be greatly appreciated! Iâm hoping some of you are either electricians or are techies that know codes, etc. Thanks!


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## Travis in Louisiana

For every 100 feet of wire run, you should go a wire size bigger for the same amperage to avoid a voltage drop. So if you want 20 amps at the gate, 333 foot run would, in theory, you would need a wire size of a #8, (2 #8 wires with a #10 bear ground). I would run romex in a conduit. I hate having any direct burial wire in the ground that someone could shovel into, but this is me. I don't think the "Panel" halfway would help you much, unless you were putting in a higher amp panel than you needed, which would cost you more. Also, look at using "Alum" wire. It is cheaper. Most terminals in box now accept both, copper and alum, with no problem. They also make a gel or paste you can put on the terminals of the alum to keep the resistance down, thus heat.


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## Ross

Welcome to HT and Shop Talk we do have a few electricians who frequent here from time to time, but you may have to be patient for them to get a chance ot see this. I'm not one but I do prefer simple and I'm thinking your junction box idea will end up being more costly with labor and exra material. You may have to shop around a bit, I know I could run that length with #8 NMD for well under $1000 retail.


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## sammyd

If you have the pipe in the ground use THWN.


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## Forerunner

I hate to be the provider of dissenting opinion, but I would never use aluminum wire for anything. 
Copper costs, but they used it back when quality and durability mattered.....for good reason.
....On that note, I have over-killed by a degree or two in my wire sizing as I install this or that, and have never regretted doing so.


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## Harry Chickpea

I would approach the idea much differently.

First, running cable in an existing underground conduit for any distance can be problematic. If you were smart enough to have left a pull line in the conduit, you will still find you need a _lot_ of lube and the pull will be hard. If you DIDN'T, you'll have to hope you can pressure a ball and line through, and that the conduit hasn't collapsed or had a loose joint, or water infiltration. Over 300 ft is about twice what the local electric company allows without an above-ground junction. Friction and wear on insulation are real problems. If there is another wire in that conduit, fuggedaboudit.

There are a number of gate designs from the 1920s that use no electricity at all, and depend on balanced gates or the pressure of a vehicle on rubber bumper. For me, a house current powered gate at that distance is dumb, and shows a lack of understanding of the parameters of the problem.

Line loss and voltage drop. Voltage drop is proportional to the current draw. Draw ten amps and the loss will be significantly more than if you draw one amp. Since the gate already has a 24 vt battery backup, IF you get a new wire through your conduit, why not just run a trickle charger and use the 24vt all the time? You could literally power a trickle charger with 18 gauge hookup wire.

One inch underground conduit running that far to code sounds velly suspicious. Are you sure you aren't trying to stuff wire in an unused one inch water line?

Since this is your first post, I'm not about to expend more effort than the above comments, which are all pretty obvious to me.


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## OkieDavid

Can't help with the wire sizing but I can offer a little "tip" on pulling the wire if you forgot to install a pull wire (or it breaks)..... Get a roll of twine and have someone feed it into the pipe while you use a shop vac on the other end to suck the twine through....Works like a charm.


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## Ray

since it is only a gate, if cost is a concern and I assume it is or you wouldn't consider to drop gage on the last leg of the run, I would consider using direct bury aluminum wire unless the appropriate gage aluminum will easily fit in the conduit and meet code, because of cost. although 330 ft. isn't that far, so it might just be personal choice, unless cost prohibitive. 
You can easily rent a simple cable plow to bury the wire yourself and not need anyone to blow in lead line and pull in pull line to install the wire in the conduit. 
A surface splice access might be costly and dropping wire gage could cause a problem later with amp draw in this situation in my opinion, it might cause the operating motor to overheat and after a time cost more that the simple cost of a bit more wire would be worth. 
As dad always said a job worth doing is worth doing correct.
pull in code size wire or plow in direct bury aluminum wire quick and easy as piece of cake, cheap and will last your lifetime. best wishes, ray


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## tiogacounty

Unfortunately, there is once again a lot of misinformation posted on this subject. Having both installed, or supervised, the installation of literally millions of feet of underground conduit and wire, I have to disagree with some claims here. First, if you properly installed 1" plastic electrical conduit, there is no reason to believe that it will be blocked, damaged or unusable at all. Unless you are in the desert, it WILL have water in it. It all does, and it doesn't matter in the least. given the information provided, you will need either #6 copper or # 4 aluminum. Aluminum is going to be roughly 1/3rd the cost and will work just fine in this application. There are millions of residential service panels, ovens, ranges and sub-panels wired with aluminum, and they perform every day for decades without incident. The pipe can be "fished" with a string, a baggie and a shop vac. Take a sandwich bag, tie the string to a corner of the opening side and feed it into the pipe. If you manipulate the bag properly, while the suction is going, the shop vac will create a suction and open the bag like an umbrella. It will travel very quickly in the pipe and you may pull a lot of water out ahead of the bag. There are also foam plugs (mice) available to do the same thing as the baggie. "Greenlee" is a common brand. A foam mouse is a cork a bit bigger than the pipe, with a wire loop built in to attach the string to. Once you get the string through, attach a more substantial piece of rope and pull it through. Now you take your three conductors, skin about a foot of insulation of each and cut 2/3rds of the strands off each wire. Use the remaining strands to make a pulling eye ,and tie the eye to the rope. Tightly tape the whole area into a streamlined shape with cheap electrical tape. Now take a qt. squeeze bottle of clear pulling lube and blow some into the pipe. Have one person rythmically, and evenly pull 2-3" of the rope in while you soap and feed the wires in. You try to fully, yet lightly coat the wires with soap as you guide them into the pipe. It's best if you have sight line contact and can hear your helper on the other end, if not have some help with walkie-talkies available. It won't talk long to get the job done. Mark the individual conductors at each end, prior to pulling, marking one white and one green. Leave plenty at each end for splicing. BTW, 330' is a real bad length. A roll of wire is 1000' and may, or may not provide enough wire to cut into three equal pieces. You can buy a flat string called pulling tape from a supply house. It will list the footage on it, like a giant seamstress tape. This will tell you exactly how long you conduit run is. A quick search online gave a price of .91 $ a foot for #4 Aluminum. my supply house is closed for the day, but that price sounds a bit high to me. Good luck. BTW, I have done gates and signs like this that need up to 1000' of conduit w/o a junction box, so really 330', or so, isn't a big deal.

EDIT: I reread the OP and noted that the total isn't 330, but 400+. At this point all the parameters entered into a wire size calculation become critical. For instance, the common use of "110" as a voltage may not reflect the reality of the job. For example, in my area we tend to see voltages in the 125- 127 range. It makes a big difference in voltage drop. The other issue is the "9 or 10" amps quoted as draw. Given that one contractor recommended a seriously undersized feed, I would want to see complete specs. on the gate opener before I started buying wire. If this 9-10 turns out to be 14-15 when the charger is humming at full load, you could really end up in trouble. OTOH, if it's closer to 5-6 amps, you might be putting a lot of wasted money in the ground.


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## TnAndy

tiogacounty said:


> I would want to see complete specs. on the gate opener before I started buying wire. If this 9-10 turns out to be 14-15 when the charger is humming at full load, you could really end up in trouble. OTOH, if it's closer to 5-6 amps, you might be putting a lot of wasted money in the ground.


Exactly.

I'd venture a "guess" that since this IS a 24v system with battery, the battery is actually doing the "heaving lifting" as far as supplying your gate opener motor needs and all you have is a small 2-5amp trickle type charger to keep the battery up since the open/close cycles per day is probably only going to be a few...and a small charger can take care of it between draws.....but that is purely a guess without the specs.


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## uhcrandy

There are also many Solar powered options.


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## ponyboy123

Might be worth checking out a small solar panel or a wind turbine.......


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