New Water Line - Should I Reduce Pipe Size For the Copper Ground?

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by AlexS, Oct 23, 2013.

  1. AlexS

    AlexS New Member

    Messages:
    20
    Location:
    Seattle
    I'm running 1 1/4" Poly 300' from the meter to the house. The main arterials inside the house are 3/4" which is adequate due to the house being 1,300 sq. w/ 1 bathroom and no outdoor irrigation. My question is whether there is any benefit to transitioning the 1 1/4" Poly to 1" copper for the last 10' of the new pipe entering the home. I'll be installing 10' of copper through the foundation to maintain a ground. I'm not sure if I should get 3/4" copper or 1" copper. My gut tells me 1" copper and then reduce to 3/4" after the shut-off.
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,227
    Location:
    Cave Creek, Arizona
    You r gut may need Activia. You will get ZERO benefits from increasing the pipe size for that short distance, especially since the 3/4 inside the building appears to be adequate.
  3. AlexS

    AlexS New Member

    Messages:
    20
    Location:
    Seattle
    You mean no benefits using 1/1/4" 300' to the meter? Or no benefit reducing from 1 1/4" to 1" copper (10' ground), then to 3/4" once inside the house? Oh, Activia? That's hillarious!!
    Last edited: Oct 23, 2013
  4. Terry

    Terry Administrator Staff Member

    Messages:
    14,749
    Location:
    Bothell, Washington
    There is a benefit to going 1-1/4" on the water service.
    At the house it's being reduced anyway. However, if you are looping the copper in, I like the 1"
    In the Seattle area, they want two grounding rods for the electrical. We quit using the copper supply for a ground years ago. The copper is still bonded though.
    When we repipe, we make sure the electrician properly grounds the main panel with two grounding rods before we cut any pipe.
    Last edited: Oct 25, 2013
  5. AlexS

    AlexS New Member

    Messages:
    20
    Location:
    Seattle
    The ground is actually for the Hot Water tank because the HW tank is located at the opposite end of the basement from the electrical panel. What did you mean by the copper is still "boned" though? Was that a typo?

    Thanks for your help!

    Last edited by a moderator: Oct 25, 2013
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,227
    Location:
    Cave Creek, Arizona
    quote; Or no benefit reducing from 1 1/4" to 1" copper (10' ground), then to 3/4" once inside the house?

    He meant "bonded". I said "short distance". 300' is NOT a short distance. You need the 1 1/4" to the building, you do NOT need 1" into the building if it is only going to be ten feet or so. I don't think the Activia is working yet. One reason for the ground rods rather then the copper water lines for grounding is that, the installers can no longer depend on the integrity of a copper system since may repairs to it could be made with plastic piping thus destroying the path to ground, plus the copper main line, which would be a major component of a "pipe grounded system" could be plastic also and thus ineffective. The electricians had to mark their entrance panels "Non metallic water line" when the main line was plastic.
    Last edited: Oct 24, 2013
  7. AlexS

    AlexS New Member

    Messages:
    20
    Location:
    Seattle
    Makes sense now.

    I thought that's what you really meant.

    I thought a gradual transition from 300' of 1 1/4" Poly to 1" for the last 10' before going through the foundation to 3/4" inside the house might be a good idea. I guess my gut thought the water would hit somewhat of a wall going from 1 1/4" to 3/4".

    Poly is not approved in Seattle through the foundation. PEX is. What do you think about PEX through the foundation or should I go with a solid pipe like copper?
    Last edited: Oct 25, 2013
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,227
    Location:
    Cave Creek, Arizona
    If the pipe is full of water, it is not moving like a depleted uranium slug so there it does not 'hit a wall" when the pipe size reduces. That only occurs when the pipe is initially filled and the water is evacuating the air in from of it. Then the water is moving like a cylindrical slug mowing down anything in its path and will react to a major reduction in size. As for your other question, you originally specified copper since it was part of the electrical ground, if so, then you cannot use plastic of any kind for the initial portion of the piping which goes from the building to the PVC.
  9. AlexS

    AlexS New Member

    Messages:
    20
    Location:
    Seattle
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,227
    Location:
    Cave Creek, Arizona
    The heater is usually grounded by the "third wire" in the supply line cable. Few installers us a 10/2, less ground, wire.
  11. AlexS

    AlexS New Member

    Messages:
    20
    Location:
    Seattle
    1950 wiring to HW tank; two hot wires in conduit from the panel and no ground.
  12. Reach4

    Reach4 Active Member

    Messages:
    1,870
    Location:
    IL
    Metallic conduit (EMT)? That does the grounding.
  13. AlexS

    AlexS New Member

    Messages:
    20
    Location:
    Seattle
    Makes sense.

    If the conduit grounds the HW tank to the panel, what was the purpose of the ground wire going from the HW tank to the cold water pipe? Before I changed to PEX inside, there was a ground wire attached to the top of the HW tank on one end and the cold water pipe on the other end. (cold water was galvanized and ran though the foundation into the ground) Bonding perhaps? The cold and hot lines also had a ground wire between them too.
  14. Terry

    Terry Administrator Staff Member

    Messages:
    14,749
    Location:
    Bothell, Washington
    There are a lot of 1950 electrial issues that have required changes.
    You didn't get outlets with the third slot for a ground either.
  15. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,227
    Location:
    Cave Creek, Arizona
    1950s wiring could be BX which is NOT an approved 'grounding method" and you might only have #12 wires because those heaters were 1500 and 2000 watt inputs, not the 4500 we have today.
  16. AlexS

    AlexS New Member

    Messages:
    20
    Location:
    Seattle
    I'll have the HW Tank grounding checked by an electrician. I don't know the difference between EMT and BX conduit. I do know the difference between #12 and #10 wire. Thanks
  17. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,529
    Location:
    North Carolina
    If the pipe supplying the building is nonmetallic then it can’t be used for an electrode.

    The electrician will bond all of the items outlined in 250.52 together to form the electrode system. If there is two rods and no metallic pipe in the ground then the two rods is the electrode system. Installing metal pipe for additional electrodes helps nothing.

    The water heater needs an equipment grounding conductor. This conductor will bond to the neutral in the panel to clear any short in the water heater and having an electrode system plays no role in this equation.

    Any complete metal water system in the building will be bonded back to the service in order to clear any fault that may occur on the metal pipe. The electrode system plays no role in this installation either.

    There is only four reasons to have an electrode system and these reasons are outlined in 250.4(A)(1)
    (A) Grounded Systems.
    (1) Electrical System Grounding. Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.


    A grounded system is a system that has a neutral. The neutral is connected to earth at the transformer supplying the building. Look at the pole holding the transformer and see the bare copper running down the pole.
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