burying power line?
 

My father just bought a parcel of rural land, and would like to out his camper on it in a semi-permanent installation (concrete slab, perhaps covered and screened in). Problem is, while power and water are run to the site, it terminates on a pole at one of the least scenic spots. I'd like to convince him that it's worth the effort to trench a power line a few hundred feet and establish a feed further back on the lot. I understand some of the challenges of running a water line, but am not at all familiar with running power. I'd assume it could just be pulled through conduit as you go, dug 30" or so down...

Any experience with such an arrangement? Thanks!

I ran 100 amp service out to my garage when it was built. I just bought 100A direct burial "trailer feed" wire at Home Depot, rented a trencher and put it 36" underground.

You might also be able to simply use a knife trencher that pulls the wire underground as it moves along then closes the trench back up - all in one pass.

I couldn't do this in my case because there were pipes and tree roots I had to negotiate.

For a camper feed, you can just use 6ga direct burial cable since you only need about 30A feed.

This is how it's done:

http://www.youtube.com/watch?v=FUQKIMqM5dw

By code SCH 40 pvc conduit has to be 18" deep minimum and direct burial 24" minimum. I'm not a big fan of direct burial due to rodent issues etc, but this may not be a problem in your area. The best way is to dig your trench and put in your conduit and water pipe, along with an extra conduit for future use ie; telephone/tv/internet. Then pull your wire into the conduit and hook it up on each end. If you tell me how far you are going and how many amps you need at the trailer I can do the voltage drop calcs for you so you know what size wire to use. PS- Don't pull your wire in as you go or the glue you use to connect the conduit can eat away the covering on the wire:eek:

Thanks for the advice, gents! I'll chat with Dad a bit and see how amicable he is to the idea of relocating the trailer. It would be a good 80 yards (or more) as a crow flies to the "other" location -- more if we run the lines along the treeline instead of across the open field.

At 240v single phase #4 copper will get you 50 amps with a 3% voltage drop at 250' one way. #2 copper will get you 1.9% voltage drop. If it is reasonable to assume that you would rarely, if ever, pull a full 50 amps at 240v then either one should be fine. Do the cost difference and see if bigger is worth it to you. I rarely regret putting in larger than needed wire as once you have power somewhere people tend to need, and use, more than they originally thought. I always give my customers the option and let them know that the only additional cost is the wire- the labor is the same. You will need 750ft of whichever size you choose,( two ungrounded conductors, and one grounded conductor/neutral) and 250ft of #6 for the ground wire. FWIW if you can run the trench as the crow flies that is best. Less wire/ voltage drop and makes remembering/ locating where the conduit is later as easy as connecting 2 points!

friend of mine told me to use schedule 80 conduit underground.guess my question is .is whats the difference??

sch 80 is a thicker wall pipe. Here they require sch 40 for pipe in the trench and sch 80 from the bottom of the trench to ground level and above.

When I put in conduit on the utility company side of the meter they will specify schedule 80 sometimes if the soil is rocky and /or unstable. They also require it to be deeper- 24' to 36" depending on the install location. If your soil is sandy and stable you can use DB120 conduit that is thinner and cheaper than schedule 40 or 80. Schedule 40 is rated for aboveground use, but obviously schedule 80 will last longer.

Check your local code on the depth of burial. In TX. they raised it from 36" to 40" I believe.

Wouldn't that be lowering it!