Page 1 of 4 1234 LastLast
Results 1 to 10 of 31
  1. #1
    Platinum Member
    Join Date
    May 2004
    Posts
    638

    Default ELECTRICAN GURUS:

    I have a question for you gentlemen? Our home has a 400 AMP service panel. This spring, I want to run an electrical line for a future small care-takers home... (two bdrm), that will be about 250-300 feet from our existing home. The line will come from the main house service panel.

    Can I go with a direct burial wire, or is that a local code decision, and what type of wire and size in aluminum or copper? The prices have seemed to have fallen with copper....would that be the best, and somewhat economical route; or go with a larger aluminum line to carry a 100 AMP service panel there?

    If I go with copper wire and conduit, what size conduit would be suitable? Will an aluminum wire size conduit have to be larger too, because of its ampacity? The property is located in Northern Calif.

    Thanx in advance for your help and suggestions.
    LEE

  2. #2
    Gold Member
    Join Date
    Oct 2006
    Posts
    361
    Location
    Wascott, WI, USA
    Tractor
    2006 Jinma 354LE w/YD485

    Default Re: ELECTRICAN GURUS:

    Check local codes, but here is a link to codes in my area, service requirements start on page 5.

    http://www.ci.lakeville.mn.us/depart...calPermits.pdf

  3. #3
    Platinum Member
    Join Date
    Dec 2006
    Posts
    680
    Location
    Coastal Rhode Island
    Tractor
    Jinma 354, purchased 2007

    Default Re: ELECTRICAN GURUS:

    I'm not an electrician but I play one on my farm.

    First off, codes are all local, your best bet is to talk to the local inspector.

    That said, there are two things you have to worry about. One is the ability of the wire to carry current without overheating. The other factor is losses due to resistance in the wire. Thinner wires can carry less current, and they have more resistance for the same length, than thicker wires.

    At that length, resistance is going to determine your wire gauge rather than current carrying capacity. A 1/0 wire will carry 100 Amps, but it will have a drop of 8%, so your voltage will be 111 volt instead of 120.

    Is that OK? This is where it gets local. The national codes are non-commital as to what is an acceptable voltage drop. You also have to think about what you're going to be doing with that electricity -- lights work fine at lower voltages, motors less well. It might be a good idea to measure what your current voltage is at the panel -- if you currently have a big drop, you probably want to be more conservative.

  4. #4
    Silver Member
    Join Date
    May 2004
    Posts
    166
    Location
    Willis, Texas
    Tractor
    FarmTrac 300DTC

    Default Re: ELECTRICAN GURUS:

    When I built my house and shop, I had the utility company run primary underground to a transformer smack dab between my shop and the house. Now, the runs from the transformer to either the shop or the house are under 150 feet. This minimised voltage drop as well as conenction costs.
    Chris

    Farm Trac 300DTC w/5140 FEL and stuff

  5. #5
    New Member
    Join Date
    Nov 2006
    Posts
    9
    Location
    Cypress, Texas
    Tractor
    Kubota 1550

    Default Re: ELECTRICAN GURUS:

    Exactly as mentioned above. Your 400 amp panels distance from the last transformer + the additional run to the new panel will dictate the need for another transformer (or not). Call the local power provider, the co. that owns and maintains the actual lines and have them come out and do an audit per your needs. In our area when we are doing projects requiring upping power needs, the utility will regularly provide transformers, bigger gauge drops, etc. The only catch is the labor is a hit and miss deal, sometime free, sometimes not.

  6. #6
    Platinum Member
    Join Date
    May 2006
    Posts
    787
    Location
    hoyt, Ks
    Tractor
    century 2535

    Default Re: ELECTRICAN GURUS:

    check your local code.
    that said, we put ours in 2" gray (Carlon) PVC, which is considered overkill in our area, but also makes future repair/work easier because i won't have to dig a new trench.
    our electric company installed a meter with 3 sets of lugs for running primary service as well - so I have the option of slaving my shop (when I get it built) off the house panel or running it's own service from the pole - which in my case will be the shorter distance.
    Erik
    Mahindra 3510, box blade, pallet forks, 6' KK mower...

  7. #7
    Super Star Member
    Join Date
    Oct 2004
    Posts
    16,854
    Location
    First organized permanent settlement in the northwest territory
    Tractor
    2003 Kubota BX1500/2004 Kubota Bx23/2005 Kubota BX1500

    Default Re: ELECTRICAN GURUS:

    Quote Originally Posted by quicksandfarmer
    I'm not an electrician but I play one on my farm.

    First off, codes are all local, your best bet is to talk to the local inspector.

    .
    There are no codes here.
    Just the way i like it.
    Tractors 2003 Kubota BX1500 / 2004 Kubota Bx23 / 2005 Kubota BX1500.
    Attachments 60'' Front Blade/48'' Rear Tiller/FEL/Back Hoe /
    60'' MMM/Clamp on Forks/48'' MMM
    South of Canton Ohio L .B

  8. #8
    Platinum Member
    Join Date
    May 2006
    Posts
    787
    Location
    hoyt, Ks
    Tractor
    century 2535

    Default Re: ELECTRICAN GURUS:


    even in a "no-code" county (state?) you still have to meet federal minimum standards.
    on the other hand, not having to have an inspection every time you turn around makes the construction process quicker.
    Erik
    Mahindra 3510, box blade, pallet forks, 6' KK mower...

  9. #9
    Silver Member podagrower's Avatar
    Join Date
    Apr 2007
    Posts
    200
    Location
    Eustis, FL
    Tractor
    NH TC 40

    Default Re: ELECTRICAN GURUS:

    Here's my two cents, and feel free to ignore it

    I do not like direct bury wire. If there is ever a problem with one wire (damaged insulation), it can not be fixed with direct burial, you will have to replace. If it is in conduit, and one wire is damaged, you can pull it out and replace it.
    That being said, 11/4" conduit would work for copper wire at minimum size. 11/2" would work for aluminum. Neither would be much fun at this distance, so I would suggest 2", which would leave room for future upgrade, and make pulling a little easier.
    Wire size: there is a table in the NEC for residential feeders which says. #4 copper or #2 aluminum is enough for a 100 amp service. If you take voltage drop into account (no more than 5% recommended to the furthest point of the system) then wire needs to be upsized to the area of #1 or #2 copper or 1/0 or 2/0 aluminum.
    For feeder conductors, I have no preference of copper or aluminum, other than copper is more fun to scrap
    One final note, if possible, make sure you get THHN (THWN, THHN-2, THWN-2) type insulation. It is a thinner coating of insulation, and this type of insulation slides easier in conduit than XHHW (XHHW-2).
    Good luck, post photos.
    NH TC40(now with FWD!), 16LA FEL, 6' King Kutter rough cut, Grapple, Pallet Forks, Subsoiler

    Some people are like slinky's, they seem to serve no real purpose, but it is still fun to push them down the stairs....

  10. #10
    Super Member
    Join Date
    Feb 2006
    Posts
    8,616
    Location
    VA
    Tractor
    JD2010, Kubota3450,2550, Mahindra 7520 w FEL w Skid Steer QC w/Tilt Tatch, & BH, BX1500

    Default Re: ELECTRICAN GURUS:

    Quote Originally Posted by quicksandfarmer
    I'm not an electrician but I play one on my farm.

    First off, codes are all local, your best bet is to talk to the local inspector.

    That said, there are two things you have to worry about. One is the ability of the wire to carry current without overheating. The other factor is losses due to resistance in the wire. Thinner wires can carry less current, and they have more resistance for the same length, than thicker wires.

    [[[At that length, resistance is going to determine your wire gauge rather than current carrying capacity. A 1/0 wire will carry 100 Amps, but it will have a drop of 8%, so your voltage will be 111 volt instead of 120.]]]
    Using the equation p=ie (Power = current x voltage) You will see that at 100A you are conducting 12kW on a 120V line. You are losing 900Watts of this (100x [120-111] in the wire. I assume you will be running both legs and taking 240V to the addition. If you divide the load equally on each leg at the addition, with 12KW you will be conducting just 50 A on each leg and you will lose only 4.5V instead of 9v on the round trip. Now P=IE = 50 X 4.5=225W lost. Still that Wattage is wasted heating the earth. If you are anticipating high loads at the addition use the biggest wire you can justify. Otherwise the electricity you pay for to heat the earth on the way there will eat back at your initial savings.
    larry

Page 1 of 4 1234 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
© 2014 TractorByNet.com. TractorByNet is a registered trademark of IMC Digital Universe, Inc. Other trademarks on this page are the property of their respective owners.