Ask Me Help Desk

Ask Me Help Desk (https://www.askmehelpdesk.com/forum.php)
-   Electrical & Lighting (https://www.askmehelpdesk.com/forumdisplay.php?f=105)
-   -   Aluminum conductor size for service. (https://www.askmehelpdesk.com/showthread.php?t=303439)

  • Jan 14, 2009, 10:20 AM
    Bammer
    Aluminum conductor size for service.
    I am installing a new service on my residence and I am installing a pole mount meter equipment box with CT metering equipment. It will have an ampacity of 400 amps and will feed both my home and garage.
    The service at the house is 120/240 volts and is a 200 amp panel.
    The run in question is 200 meters in length. And will be installed under ground from the metering equipment to the home.
    My question is... with a 3% voltage drop at 200 meters underground. What size of aluminum condutors are required to feed the 200 amp 120/240 volt panel at the home?
    Please let me know,
    Thanks.
  • Jan 14, 2009, 11:03 AM
    KISS

    It's not going to happen at 656 feet.

    There is some confusion with 400 A service and 200 A panels.
    Is that 200 meters at 400 A or 200 meters at 200 A?

    In any event, it still won't happen. Your going to need primary service (High Voltage) to get it closer. In which case, you will need to talk to the Utility to figure out what their requirements are.
  • Jan 14, 2009, 11:21 AM
    Bammer
    Aluminum conductors
    For: Keep It SimpleStupid

    I thought I was clear, Sorry.

    The utility feeds a panel referred to as a JS4 (customer owned). It's a 400 amp distribution panel that feeds other services. I am going to use this install to feed my garage, one 200 amp panel and my home, another 200 amp panel. Drawing at the most, 400 amps at the distribution panel, where the metering equipment is also installed. I know it can be done, all that I require is a conductor size to supply the 200 amp panel, from the JS4 to the house. The distance is 200 meters underground.
    Hope this explains.
  • Jan 14, 2009, 11:53 AM
    stanfortyman
    I agree. 200m is WAY too far to go with secondary voltage (120/240). You need to put the transformer closer to the load.

    Also, 3% total for the service is low. 5% total would be more realistic.
    Also, what number are you using to figure this VD? Not the full 400A I hope.
  • Jan 14, 2009, 11:53 AM
    stanfortyman
    Please do not start a whole new thread to answer a question. Simply reply in the existing thread.
  • Jan 14, 2009, 12:18 PM
    KISS

    <Threads merged>
  • Jan 14, 2009, 12:32 PM
    stanfortyman
    Nice, you have a total of two posts yet you have already left two negative comments for two of us.

    Mr. Bammer. I am quite sure how to size the conductors. If you are not then maybe you should not be tackling such a large project that is obviously over your head.

    If you wind up doing this I wish you luck. You're going to need it!
  • Jan 14, 2009, 12:38 PM
    Bammer
    Turns out, all I'm going to get here is a bunch of smart comments. I ask a simple question and all I received was advice on how I am in over my head. That is not what I was looking for. I wanted a conductor size, I did not get it. Thanks for once again.. wasting my time KISS.
  • Jan 14, 2009, 01:04 PM
    stanfortyman
    OK Skippy. You want it, you got it.

    You would need either 1000mcm CU or parallel 500mcm CU.
    You will have an impossible time terminating these conductors and they will cost approximately $35,000.

    Happy??

    If you don't know what you are getting yourself into maybe you should not get yourself into it!
    Like I said, good luck.
  • Jan 14, 2009, 01:22 PM
    KISS

    Or assuming 60 deg termination THHW (if permitted) Wet location Aluminum 1-3 current carrying conductors in raceway.

    Continuous load of 200 A, OCPD sized for 200A

    1750 kcmil conductors
    Grounding conductor 350 kcmil

    Will yield a 2.7% voltage drop at 660 feet.

    You may be able to reduce the neutral size. Neutral doesn't count as a current carrying conductor.

    And, I guess you will need two of these unless the other one is in place. Conduit would have to be bigger if all in the same one.

    Do us a favor and post the estimated cost.

    Why not ask the utility if they can do remote metering on a primary feed to a dry location such as your garage where you will provide the necessary equipment.

    This does not include the recommended conduit size.
  • Jan 14, 2009, 02:52 PM
    donf

    Bammer, I'm curious as to where you are located.

    240 VAC the allowable voltage drop is 7.2% 120 VAC the allowable drop is 3.6%

    No one here is trying to poke at you. You really need to start this discussion with the power company. Running secondary transformer cable 200 meters is not a wise thing to do.

    It's the power company that sets the distances they will allow off their transformers. Power Companies are not bound by the NEC code.

    Power Companies use their own code book. Power Companies typically own everything right up to the service head.

    Electricians and the NEC own the requirement and codes from the service head throughout the structure.

    Good luck.

  • All times are GMT -7. The time now is 09:51 PM.