Underground electric wiring - meter to grain bins

I had some pretty strong winds two weeks ago that took down some trees which took down electrical wires to my grain bins on two farms. I am feeling like it is time to go underground with them. One bin site just needs 110 volts for 1 hp aeration fans, unload augers, and sweeps. Can I just direct bury a certain type of sheathed cable????? What do you do when the cable comes out of the ground at the bin (put it in a plastic conduit)?? The other bin site needs 110 and 220 for unload augers, fans, and a stirator. Can the same type of cable still be used with an additional wire???? How deep are most wires placed in the ground. My plans are to eventually involve an electrician. Any other ideas are appreciated. Thanks

refer to your local electrician as many things enter in to this. distance run from main panel , total load if all fans and auger motors are running, future up grades, are you going to plug in an engine heater or battery charger some time. possibility you may need to use a welder or tools at bin. some times it is cheaper to run 240 volt service rather than 120 due to wire size required. as to depth local code may dictate this, around here most underground is buried about 3 feet and water lines 4 feet

There is a type of wire known as underground feeder "UF" that you can directly bury. I would bury the wire as deep as possible. The deeper you go lessens the chances of the wire being damaged. I've seen it just buried a couple of inches and they had enough erosion the wire was exposed and cut with the lawn mower. Don't buy any more than necessary. The stuff is a terrible job to strip the insulation off and connect.

I hate uf cable. I don't know how many times I hard to locate broken wires. It's quick and easy but when it fails it sucks!

I don't know where you are, but our power company wanted the wire placed in a tile.

You'll need to know the amp load for each run.

Each motor will have a tag showing the FLA (full load amps). Add all the motors together that will be running at the same time, and any other lights, any outlets, etc. Then add at least another 20%. That will give amp load. Then use a ampacity chart to determine the wire size. If it's a long run, say over 200ft, go up a size.

You can use direct burial cable, or run PVC conduit. I prefer the conduit, that way if there is a problem you can repull the wire without having to dig it up. Conduit is cheap.

Either way, do bring conduit up out of the ground to make the connections. Don't make any connections under ground or in an inaccessible place. The depth depends on local code (if applicable) and where it will be run. If a non traffic area, no reason there will be any digging, 18" should be sufficient. If under a driveway, especially heavy vehicle traffic, it will need to be deeper.

For a 120v circuit, you will need a black, white, and green stranded THHN wire (if running in conduit) or a "xx ga 2 conductor with ground" UF-B cable. For 220v, 2 black, 1 white, 1 green, or "xx ga 3 conductor with ground" UF-B cable. I would suggest running 220v to both, just so it will be there if needed.

First thing is to check your local building codes, as they can vary wildly from one area to another. Some places will allow UF wire without conduit, while others will require everything short of the promise of your next-born child! (ok, ok...seems that way sometimes!) Thing is, if you're replacing wiring to buildings or remote equipment, an inspector may come along at a later time and, if there was no permit or if nothing was signed off, they can actually force you to either shut down those lines or rip them out and start over, often with hefty fines. (your friendly neighborhood gov't overreach!)

Also, you need to check with your insurance company to see if they allow for any work to be done on your part. Some insurance companies will be OK so long as a certified electrician checks out and passes your work, while others don't want your hands-on involvement at all. Used to be, many would allow you to do everything EXCEPT making the actual connections, but has been a lot of years since I delved into this.

As for what type wire, size, breakers, conduit, etc., that'll all be covered in your local building codes. Also keep in mind that there are usually multiple codes involved here - local, state and federal building codes, and also local, state and federal electrical codes. In many cases they will be the same, but codes seem to change pretty often.

If you don't have insurance, then guess it's up to you how much risk you wish to accept.

On a final note, if your local codes and insurance allow for you to simply bury UF wire, I would still run it inside some sort of conduit. If there is no conduit requirement, I would still recommend running the wiring in something like black water line. It's pretty cheap, yet helps protect the wiring from accidental damage from digging or from over-zealous burrowing varmints!

I heard of a farmer who had a problem with lightning striking the wire underground and blowing his load center off the wall. He finally buried it as deep as a backhoe could dig.

Personally I think lightning may not be an issue for most, but this farmer's grain bins were on a hillside next to the river. It was like his grain bins were lightning rods or something.

It sure is a shame to go to the expense of burying wire and wiring up the ends....

And not putting in 220v wire to handle a 5hp motor.

Especially at a bin site, even old small bin site.

One would really really kick themselves in future years for being so short sighted, and doing such a poor job when all the expensive parts are already being done; all it takes is a little more wire is all.

Sleep on that for a few days. Please. I'm as frugal as they come, and I sure understand a budget.

But just think about it a little bit?

Paul

You tell a man about how he should investigate and make installations to code then suggest that he might want to run UF cable in conduit? OR BLACK WATER PIPE.

(quoted from post at 00:20:27 03/20/17) You tell a man about how he should investigate and make installations to code then suggest that he might want to run UF cable in conduit? OR BLACK WATER PIPE.

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No body said "BLACK WATER PIPE"

Put in conduit, doesn't cost that much and if you need to repair or change something 10 years from now you will have long forgotten the cost. When we bought this place I rented a ditch witch and buried about 500 feet of two inch conduit in 3 runs. For the out buildings I used the 4 conductor aluminum drop wire available at Home Depot or Lowe's. Think it's made for mobile homes and isn't too expensive. If you use UDF or whatever it's called, do not run the white indoor wiring even if in conduit, use the direct burial grey wire.

As has been said do not put any splices or connections under ground. It is impossible to keep water out of underground conduit and underground splices will go bad.

Not an electrician but

(quoted from post at 22:20:27 03/19/17) You tell a man about how he should investigate and make installations to code then suggest that he might want to run UF cable in conduit? OR BLACK WATER PIPE.

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Yes, I mentioned "black water pipe". Please read the full post and don't take things out of context.

Both UF ("underground feeder") and USE ("underground service equipment") may be buried directly without conduit. Whether or not you put them in conduit is up to you, but there's a lot of direct-buried UF and USE in service. Bury it deep (2 feet minimum), leave some slack and it should be trouble-free. If you have particularly rocky soil you probably want conduit. The conductors must be in conduit where they enter and exit the ground, regardless of whether they're in conduit the whole distance.

Run four conductors to each bin site (two hots, one neutral and one ground) and install a subpanel at the bins. The subpanel needs its own ground, and the ground must be separate from neutral in the subpanel. As someone else said, there's no reason not to run 240 now, even if you don't need it. Sooner or later you probably will.

How much current do you need? 100 amps is probably a good choice; a 100 amp weatherproof subpanel will have space for a half-dozen breakers. It doesn't cost that much more to run AWG 2 aluminum USE as to run AWG 12 copper UF, and you'll have much less voltage drop with the heavier cable.

Exactly how heavy your conductors need to be depends on the distance. AWG 2 aluminum is good for 100 amps for 100 feet or so. Longer distances require heavier conductors.

The hard part is digging the ditch - so if it were me I'd put it in conduit. I generally install an expansion fitting where the conduit comes up out of the ground, and terminate it in a PVC junction box
It's not ideal, but there's nothing wrong with installing UF cable in poly pipe - it just adds more physical protection.
Pete

yes put it under and in conduit, keep track where they are for future. flex when come out

Andy, good questions and as usual plenty of answers anytime an electrical related question is posted. First and most important is CHECK WITH ANY GOVERNING LOCAL AUTHORITY as its what they say NONE OF US or how we did it or think it should be done that matters. That being said and even though I've been retired from electrical power distribution design for yearsssssssssss lol here are my thoughts.

1) If youre already paying for labor and digging trenches its not that much more expensive to go ahead and run 120/240 volt services to all the locations.

2) Subject to local authority (if any exists??) you can direct trench bury Three Conductor PLUS Equipment Ground Type UF Underground Feeder UF Cable consisting of Two Hot Ungrounded Conductors (L1 & L2), One GrounDED Conductor (Neutral), One Equipment GroundING Conductor. If required I liked to place sand in the trench bottom and over the top of the cable along with yellow identifying caution tape.

3) It may cost more but buried conduit and four individual THWN encased conductors is a good method especially if you ever have trouble. In our jurisdiction it was necessary to encase the conduit in concrete if placed under a driveway etc.

4) In either (UF or Conduit) system I specified Rigid or IMC Conduit with appropriate wide sweeping ends, any necessary expansion, appropriate plastic bushings if needed where it comes out of the ground for entry into the building.

5) At the new locations install appropriate sized SUB PANELS having electrically insulated and isolated Neutral and Equipment Ground Busses.

6) I ALWAYS specified any buildings electrical services be Grounded to all readily available local "Grounding Electrodes" such as "Made Electrodes" (driven copper ground rod or rods) or buried conductive utility pipes or structural building steel or buried grids ete etc

That's how I designed back in the day, your local jurisdiction (if any exists) may do it differently and some here may do it differently. Once the loads are computed and distances known you can use charts to figure wire sizes to allow for voltage drop and adequate ampacity

I SUGGEST YOU USE LOCAL AUTHORITY AND THE NEC AS A MINIMUM DESIGN GUIDE VERSUS ANY OPINIONS POSTED HERE

John T Long retired electrical power distribution design engineer so no warranty, do as you please is fine by me

I have about 100 feet of 10 gauge UF feeding the submersible pump in the well. The pump runs on 110. Wire is buried about 12" deep. No farm ground. No heavy machinery. It is ALL lawn.

"First and most important is CHECK WITH ANY GOVERNING LOCAL AUTHORITY as its what they say NONE OF US or how we did it or think it should be done that matters." Well spoken Mr. John T. Sir.

Coworker sold his homestead and moved his trailer house to a new site stuffing all the extra money in his pocket from his current high priced real estate sale. Asked me to help him install his service. Never mind what I said or felt, he was calling the shots and I went along for the ride.

At his old residence, some 35 years old, he ran Size 0 AWG service wiring which he dug up and brought to the new site. We buried it in conduit at the new location. Some time later I get a call that we need to dig up the 0 and install 00 per county code......................gotta have a green tag on the meter base to get the meter and the tag was RED!

Oh forgot the punch line. The guy held a BSEE and had been working as such for that 35 years....but not in power distribution.

Even the direct burial cable should be pulled into a conduit .
May as well pull 120/240 out to the first site as it will be required someday.

300-5 will tell you the burial depth . It varies with conditions. If you have vehicular traffic it is deeper than others . For normal across yard 18 inches is fine. PVC pipe is cheap and good insurance for future work. Use large radius sweeps at each end.

You didnt mention any distances but something to think about is your amp loads drops by 1/2 when you use 220 instead of 110 to power up those motors and I would about bet that all of them can be converted by switching a couple wires. The savings in wire could be substantial. Plastic conduit is cheap insurance against future problems for sure.

Out in the country a lot of non conforming conduit is used. Tile, water pipe, etc.

This may not pass your electrical inspector. Be careful on these suggestions.......

Paul

Several people suggest pulling the underground wire in conduit. Use PVC schedule 40, and if you drive over the area pour some concrete over it for several feet past the roadway. The wire will last longer and be easier to fix in the unlikely event you ever have a problem. Buffing direct without conduit and you will have a problem, especially with aluminum.

So, as you can see, it's simple to dig a trench, spool out some wire, backfill, and turn a screwdriver to tighten a few nuts.

The labor on doing this is easy.

What's difficult is sorting out the many details of what you want to end up with. That's why the electrician gets paid a lot. The details of your exact location and needs......

you will need direct burial rated cable, or conduit and wire rated to run in conduit underground. (They use different coating, some rely upon being in touch with cooling dirt, some can sit in the air inside a conduit without melting, some can work either way, etc. all types of coatings for all types of uses, match them up right to what you are doing!)

You need the wire buried at least into the teens of inches deep. Different locations use different versions of the Electrical Code Book, so they might differ a bit. You might need to go deeper in special cases, and you can always go deeper if you want. Many just trench 2 feet to give a little extra cushion?

You need metal or plastic conduit protecting the wire when it leaves the ground and cones up the side of a pole or building. Think everyone uses plastic these days.

Your wire needs to be sized for the load you want to carry, plus it needs to get bigger as the distance increases. Wires carrying electricity heat up. Maybe only a degree or two with a small load, but as the amps increase and/or the wire is longer, it creates more heat. This heat is wasted energy, and reduces the volts you get at the far end. And so this is why we need to size the wires for the correct amp load and distance of the wire.

A 120 service uses 3 wires. Hot, neutral, ground.

A 240 service uses 4 wires. Hot hot, neutral (used with one of the hots to make 120v), and ground.

The 4 wire 240 service is -much- more flexible and offers you a lot more options. As I said below, it would be pretty foolish to go to all this expense and then leave out that one extra wire to save a very few bucks......

If you could tell us what size motors and how many lights and so forth you use at each bin, and the distance between the service pole and the bin site, several could give you a wild guess as to what size wires you would be looking at?

It sounds like you just want an idea of what you are in for, and what it might cost?

Many times electricians have a cheap helper with them to do the rough work - the digging, the unrolling wire, etc. and the licenced electrician just designs the plan of what is needed and does the final screw turning to get the right wires connected proper. It is possible to find an electrician that will do his parts, and let you do the grunt work of digging trenches, unrolling the wire he specifies, etc. now be careful on this - you cant expect him to give up his income either, he needs to get paid for those expensive, decision making parts. But it might help you cut costs if you find a guy willing to let you do the simple parts.

When I put up my machine shed I was running water pipe and draibage tile, and had a trench about right from the power box to the machine shed I put up. The electrician was happy, he didn't have to bring his trencher out, and saved me a lot of money on that part of it..... He was overworked and so he could get paid for the expensive parts, but didn't have to waste time on the flunky work.

Paul

Either get an electrician or for insurance reasons, build to your local code. We always buried cable 3 ft deep in proper duct. We only used concrete if we couldn't get three feet. Doesn't have to be thick wall except where it comes out of the ground. In our area, if you use proper duct you don't need direct bury wire. We always used three wire cable or three wires a little bigger than required for future upgrades. Install an expansion joint on both ends so when the ground settles the pipe will not pull apart. If you're in rocky ground, bed the duct in sand. Fill the ditch to a foot from the top and lay marker tape and then fill to the top. I hope with all the other suggestions this helps.
Dave