Page 1 of 2 12 LastLast
Results 1 to 15 of 20

Thread: Electrical question

  1. #1
    Join Date
    May 2004
    Location
    columbia, sc
    Posts
    708

    Electrical question

    Ok this isnít really very workshop related except one end of the conductors terminate in a Sub panel in my workshop

    essentially I have a 6-2 or 6-3 direct burial cable running from the shop to a pump way down at the River. What Iíd like to do is cut that cable about 50í in and put a Sub panel outside. Is this doable? It seems like Iíd have to have a good way to splice in a section since thereís no slack because I still want power down at the river as well as some additional branches Then Iím not sure how to handle grounding at the new sub panel.

    thoughts?

    it would be very tough to run a new set of conductors from the sub panel in the shop
    Bob C

  2. #2
    Join Date
    Jul 2007
    Location
    NE OH
    Posts
    1,733
    They make underground splice kits for UF cable, but I haven't seen them for 6 gauge. You can get 6 gauge underground splice kits for single conductors, so you could use three of those, and then get one kit for larger wire, like 1/0 or bigger and use the heat shrink sleeve from that as an an overall insulator. Make sure you slide it on one of the cables before you do the splices!

    You will have to drive a ground rod to ground the subpanel.
    --Certainty is the refuge of a small mind--

  3. #3
    Join Date
    Jul 2005
    Location
    Eastern Iowa
    Posts
    640
    It sounds like that pump is a 240 volt pump.
    When running a branch circuit you only need to run the conductors necessary for the circuit. It is possible it is in fact a 6-2 wg uf cable and the white conductor is being used as a phase conductor. If so, you could still run a sub panel, but would be limited to 120 volts. That may entail switching out your pump.


    A sub panel will require


    current cable:
    phase conductor(s) - one if planning a 120 volt sub, two if a 240 (black and/or red?)
    neutral conductor - (white?)
    equipment ground conductor - (green or bare copper?)


    then at your sub location you will need a panel and a disconnect (if under 2020 code).
    one or two ground rods and a new grounded electrode conductor (usually bare copper)
    length of cable needed to reach the remaining currently buried conductors
    *****************
    At the new sub location
    phase conductor(s) to phase lugs
    neutral conductor to neutral lug
    equipment grounding conductor to a separate grounding bar
    - remove the bonding screw, the neutral bar must not be bonded to the box or the equipment grounding bar
    - drive the ground rod(s) (one if you can prove 25 ohms or less, else two. If two, space at least 6í apart
    - land the grounded electrode conductor on the equipment grounding bar in the panel and the buried grounded electrodes.
    - you can not mix branch circuits neutrals and equipment grounding conductors in the sub panel, they must land on the appropriate bar.


    At the splice
    splice kit listed for direct burial for each conductor, one such kit
    https://www.gordonelectricsupply.com...ce-Kit/6282559
    Paul has already discussed this.
    Or bring it up and add a junction box.
    edit: I would not splice. I would run new cable from the new sub panel to the pump.



    Last edited by Charlie Velasquez; 05-25-2021 at 8:32 AM.
    Comments made here are my own and, according to my children, do not reflect the opinions of any other person... anywhere, anytime.

  4. #4
    Join Date
    Feb 2014
    Location
    Lake Gaston, Henrico, NC
    Posts
    5,780
    Just do a search for "splice kit 6 awg. water pump". I like the kits for submersible pumps better than those sold for "direct burial".

  5. #5
    Join Date
    May 2004
    Location
    columbia, sc
    Posts
    708
    Good point on the number of conductor ...6-2 vs 6-3. Yes it’s a 220V pump. Ill
    need to check and that may make this idea a non starter as I do need 220 at that panel. I guess you still need to run the ground between the two panels even if you install ground rods at the sub panel
    Bob C

  6. #6
    If the pump requires 6/2 or 6/3, putting in a subpanel won't work well. If you have additional loads through the subpanel and the pump cuts on, you will likely overload the 6/3 between your main panel and the subpanel.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  7. #7
    Join Date
    May 2004
    Location
    columbia, sc
    Posts
    708
    The pump doesn’t pull that much current. The wire was sized that big due to distance

  8. #8
    Join Date
    Jul 2012
    Location
    Punta Gorda, FL
    Posts
    2,994
    Quote Originally Posted by Bob Cooper View Post
    The pump doesnít pull that much current. The wire was sized that big due to distance
    If the wire was correctly sized for voltage drop, then there's no room for additional loads to be added. Whatever the pump draws is only part of the full load presently on the #6 wire.

    You have to calculate voltage drop for all expected loads coming from the new sub panel and install the correct wire size feeding the new sub panel. Then you can use the existing #6 to feed the pump from the sub panel. Here's a VD calculator to help determine if the existing #6 can handle whatever loads might be added due to the sub panel insertion in the run: https://www.southwire.com/calculator-vdrop
    ďTravel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

  9. #9
    Join Date
    May 2004
    Location
    columbia, sc
    Posts
    708
    I’m just curious. When you have a Subpanel located remotely such that it needs its own ground rods why do you need to run a ground between them? Isn’t the purpose of the ground to allow current to go to ground potential in case of a short, etc. under normal circumstances no current should flow over it right?
    Bob C

  10. #10
    Join Date
    Apr 2020
    Location
    Tennessee
    Posts
    282
    Blog Entries
    1
    Quote Originally Posted by Bob Cooper View Post
    Iím just curious. When you have a Subpanel located remotely such that it needs its own ground rods why do you need to run a ground between them? Isnít the purpose of the ground to allow current to go to ground potential in case of a short, etc. under normal circumstances no current should flow over it right?
    Bob the purpose of a ground rod is often misunderstood. Your electrical system doesn't need the ground rod at all to function or even to have the breaker trip. If you draw the circuit out you will see that the ground rod never sees current even in the event of a short circuit. The purpose of connecting your ground to a ground rod is to create a reference to earth potential which can drain any static voltages to earth. The ground rod gives a path for lightning to travel to earth. Basically, it maintains your ground circuit at approximately earth potential. But it can not conduct the AC voltage in your electrical system. The resistance of "earth" is actually pretty high with any amount of separation.

    The ground wire is the key to creating the fault path which can ultimately clear the fault by a breaker trip. The ground is connected to conductive components housing your electrical components. That way if a short to a panel or other conductive component occurs then the circuit is completed and the breaker can trip. This is why you connect the neutral to the ground. That is actually the key to the safety ground in terms of clearing a short circuit and not the ground electrode. Otherwise, the short would cause the conductive component to be at the raised potential and you could be shocked when you touch it. Disconnecting the ground rod would not affect this fault clearing function.

  11. #11
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    57,360
    Quote Originally Posted by Eric Arnsdorff View Post
    This is why you connect the neutral to the ground. .
    Point of clarification here...the neutral and ground are only bonded at one point in the entire system inside the meter...in the main panel. There is no bonding/connection between neutral and ground anywhere beyond that.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  12. #12
    Join Date
    Apr 2020
    Location
    Tennessee
    Posts
    282
    Blog Entries
    1
    Quote Originally Posted by Jim Becker View Post
    Point of clarification here...the neutral and ground are only bonded at one point in the entire system inside the meter...in the main panel. There is no bonding/connection between neutral and ground anywhere beyond that.
    Thanks Jim! Yes, exactly!

    My wording was poor but yes only make the one connection where your mains come into your main panel. From that point forward make sure the ground remains separate from the neutral.

    I was attempting to indicate that the circuit which trips your breaker in a ground fault is the connection that is made to the neutral. The current flows through the ground wire to this neutral connection which is connected to one side of the coil in the transformer and through the coil which is where the potential is created. This makes the complete circuit which does not involve the grounding electrode.

  13. #13
    Join Date
    May 2004
    Location
    columbia, sc
    Posts
    708
    Thanks Eric...makes perfect sense and pretty obvious that the breaker wouldn’t trip if the path back to the main panel
    wasmt there. I never really understood the true purpose of the ground rod since as you point out they may be at a common reference they are in no way connected.
    Bob C

  14. #14
    Join Date
    Feb 2021
    Location
    Western North Carolina, USA
    Posts
    21
    Hi Bob,

    As Mike and Julie note, you don't want to be overloading your pump circuit.
    One way to deal with this is to have your pump on a breaker in your sub-panel.
    When you are using the circuit for other loads, just turn the pump off.
    Remember to turn the pump back on when done!
    A bigger pressure tank might be helpful at the house.

    Thanks and good health, Weogo

  15. #15
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
    Posts
    6,082
    How much power do you need at the midpoint? It may be easier and cheaper to install a small solar panel and battery. Cheap enough for a light or radio.
    Bill D

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •