1000+ft from the road... Long run to the grid or Generator?

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  • rpvietzkerpvietzke Registered Users Posts: 40 ✭✭
    Re: 1000+ft from the road... Long run to the grid or Generator?
    icarus wrote: »
    Consid getting a price from a wholesale electrical house. They ought to be able to beat the HomeDepot price pretty easily. You might also contact the utility. Perhaps they can supply you with the wire. Personaly, I would go with direct burial and not bother eight he conduit. If I needed a pipe simply to fish through, I would consider light weight PVC instead. I suppose it depends to a great deal on your code/inspection authority. 18' really ought to be pleanty deep if you don't have any reason to molest the trench, ie,plowing or landscaping etc.

    Tony

    Thanks. The town where this is has -zero- zoning or inspection regime. You do have to have a septic plan registered with the state and have a certain level of insulation in new construction due to State rules, but there is no inspection regime. That said, the local power company has requirements up to the meter socket. They indicate the "RV hookup" is common and they have seen what I am looking to do many times before. IF I want them to put the meter up the hill, they require an 18" wide trench, sand around the conduit, etc. They will install it too, but quoted around $20-25K to do the work. A local electrician wasn't much cheaper.

    The "trench" will be through the woods. Plenty of chance that roots and varmints will find it over time, but no worries about vehicles, plowing or landscaping.

    Rob
  • Ethan BrushEthan Brush Solar Expert Posts: 235 ✭✭
    Re: 1000+ft from the road... Long run to the grid or Generator?
    I believe that if each conductor terminates on a different device (such as a fuse or circuit breaker), then the two conductors are not technically in parallel. My belief is not based on any advanced understanding of NEC, but is based on comments by 'inetdog' in another thread.

    Regardless of code, this should only be done if the reason for the 'parallel' conductors is to reduce voltage drop. If the reason for multiple conductors is to increase ampacity, then the use of multiple fuses/CB will lead to a cascading failure of the fuses/CB.

    Thats an interesting idea, I never considered that. I supposed you could join the conductors on the load end, and feed the line end with two separate breakers then they are not in parallel and you can then use any size you want. However than you have two branch circuits or feeders and per the NEC you cannot feed a structure with multiple feeders or branch circuits. You may want to size each breaker at half the ampacity of the wire because a fault get be fed from both breakers. Although if this feeder is outside its entire length than you actually dont need any overcurrent protection at all. Well this is all irrelevant anyway since its sounds like the OP doesnt really have to follow code.

    That /urd is pretty cheap. You have a few choices
    1) use 3 conductor wire, with two hots and one ground and use a transformer at the load end to get your 120/240 split phase. (NEC compliant)
    2) use 4 conductor wire with two hots, neutral, and ground then no transformer required (NEC compliant)
    3. use 3 conductor wire with two hots and a neutral and "rebond" the neutral and ground at the load end, no transformer required (was NEC compliant until 2008 )
    4. use two conductors, both as hots, 240 ->120/240 transformer on load end. There would not be an EGC, which sounds unsafe but the only the thing EGC does in this case is provide a path back to the source for a line to transformer case fault which in the scheme of things is quite unlikely. Everything fed off the secondary would return to the secondary winding so all loads would be grounded back to the source.

    Note that options 1 and 4 could use #6 wire while 2 and 3 require the #2. This is because the transformer allows you twice the voltage (yes if you used two smaller equally balanced loads 2 and 3 could use smaller wire too, but im assuming that isnt likely or practical so your charger would effectively be using the feeder at 120V completely unbalanced).

    One more suggestion is you could check with your utility to see if they provide a certain amount of feed free for new accounts. I know mine will give you 200 feet for free which will cut a nice chunk off.
  • rpvietzkerpvietzke Registered Users Posts: 40 ✭✭
    Re: 1000+ft from the road... Long run to the grid or Generator?
    One more suggestion is you could check with your utility to see if they provide a certain amount of feed free for new accounts. I know mine will give you 200 feet for free which will cut a nice chunk off.

    Thanks for all of this. I suppose I'm most likely to use the 2008 approach... Although I could pretty easily pull a #6 (or even a #2) alongside for an additional ground.

    Already counting on them to do the first 200 feet and then some to get to the landing where I can put the meter socket... Its another 1200 feet to the house from there.


    Rob
  • Ethan BrushEthan Brush Solar Expert Posts: 235 ✭✭
    Re: 1000+ft from the road... Long run to the grid or Generator?

    Yeah I woud go with option 3 or 4. The wire cost difference isnt really that big a deal and even though a 3KVA transformer wont cost much, that will eat up a chunk of the smaller wire savings. For my situation I would go with option #4, going with the small wire, small conduit, small trench is a big gain because of the mini trencher I already have, but I have to stick with 3/4 or maybe 1" conduit. If I went with bigger wire I would need to either rent a trencher or use my backhoe which would be more money and time. If you have to rent a trencher regardless, probably anything you get will to at least a three inch trench anyway.
  • BB.BB. Super Moderators, Administrators Posts: 32,741 admin
    Re: 1000+ft from the road... Long run to the grid or Generator?

    Do you have anything else to run at the same time? Telecommunications, water, etc. to between there and here?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • oil pan 4oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    Re: 1000+ft from the road... Long run to the grid or Generator?

    Code says the smallest service drop or lateral service conductors that can be paralleled is something fairly big, like 1 or 0 gauge wire and bigger.
    #3 isn't code any more? what is the world coming to.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • rpvietzkerpvietzke Registered Users Posts: 40 ✭✭
    Re: 1000+ft from the road... Long run to the grid or Generator?
    BB. wrote: »
    Do you have anything else to run at the same time? Telecommunications, water, etc. to between there and here?

    -Bill

    Funny enough you ask... The local telephone company recently buried a fiber optic cable up my "driveway" as part of an ongoing project to replace all the copper drop lines in southern Vermont with fiber. At the urging of family who was worried I would lose an arm with a chainsaw in the woods when working alone, we had put in a phone line several years ago. Through a strange set of circumstances, the telephone company chose to bury that copper wire at their cost instead of letting me run it on top of the ground. Then they won a federal stimulus grant to upgrade their infrastructure and soon they replaced the copper with fiber all the way up the driveway... That path is probably 1800-2000 feet given the switchbacks in my driveway.

    I'm not complaining. I find it incredibly ironic that my off grid cabin has a buried 1G fiber optic service that is supported by my monthly $39.95 DSL bill, especially given the huge estimates we've seen for buried electric. Water? Gas? No, this is rural Vermont. Water comes from deep wells and gas comes on propane trucks... Strangely, Internet comes on world-class buried optical fiber.

    Rob
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