Galvanized pipe corrosion

Discussion in 'Pumps and Tanks Well Forum & Blog' started by Rutherfordman, Mar 9, 2009.

  1. Rutherfordman

    Rutherfordman DIY Member

    Messages:
    46
    Location:
    North Carolina
    I live in western North Carolina. Most of our wells where I live are deep wells with submersible pumps supplying more than one property depending on the well yield. Most pumps are 3-5 HP. These wells were installed in 1997 and several in the past year or two have had holes develop in the 1-1/4" schedule 40 galvanized drop pipe. I examined some of the pipe that was replaced and it appears the problem is corrosion from the outside in at the exposed threads and just below them at the couplings. The couplings appear to also be galvanized steel. There are also a few corrosion spots along the length of the pipe but these are few. The wells range in depth from 250 to 800 feet deep. Is it normal for galvanized pipe to corrode this quickly in this application. The water is not "hard" in my area. Mine has not had the problem yet but I can see my days are numbered and when it needs replacing I would like to get the most bang for my buck. I am the only one currently using my particular well so I will have to bear the full cost. Thanks for any help anyone can give me.
  2. Gary Slusser

    Gary Slusser That's all folks!

    Acidic water (low pH <7.0), electrical ground stray current problems and bacteria of varying types could be the cause of the holes.
  3. Rutherfordman

    Rutherfordman DIY Member

    Messages:
    46
    Location:
    North Carolina
    I will check the PH for sure. The water is very clear and clean and up until recently I did not even filter it. I put a sediment filter on it a few months back and I don't see much in the water at all. My well is basically on the top of a 2,400 foot mountain and is just over 800 feet deep. I do get quite a bit of lightning in fact you may laugh but after buying the 3rd control box, having them put lightning protection on my house (it got hit the 3rd month after I moved in)and pump house and surge protection (cheap) on the pump breaker panel and house panel my control box still got hit whenever lightning was close by. What I found besides learning how to rebuilt the boxes is I have a 30amp plug on my control box power/ground and I basically trip the breaker and unplug the box during thunderstorms. Just tripping the breaker sometimes would not do it, lightning still got the box. I have been using this method for several years without any problems. I am no well man so I may be doing something wrong. I hope tripping the breaker alot and unplugging the box won't hurt anything besides wearing the breaker out. I am wondering if all that lightning is doing something to these wells. I am fascinated about these pumps being 777 feet down and giving you 60-70 psi water. I have a 3 HP SS Grundfos pump and I guess I am now on borrowing time so if the pipe goes I guess the smart thing to do is replace the pump too. I notice they put a band on the plastic well casing with a huge ground wire. Why do you ground a plastic casing?
  4. Gary Slusser

    Gary Slusser That's all folks!

    Yes lightening could do it. That ground on the PVC casing is useless and wrong if that is how they grounded the house. The newest electrical code calls for either bonding or grounding the well casing I can't recall which, but it does no good if the casing is plastic and can cause a big problem if it is supposed to be a ground.

    To my knowledge, turning off the breaker can't hurt a pump. The pressure switch does the same thing many times a day.
  5. Waterwelldude

    Waterwelldude Well driller,pump repair. and septic installer

    Messages:
    303
    Location:
    Texas
    That ground in supposed to go from the drop pipe(the pipe the pump is on) to a ground rod driven beside the well.
    Nine out of ten time, the hole is caused by electrolysis. Grounding the drop pipe will stop that from happening.



    Travis
  6. Gary Slusser

    Gary Slusser That's all folks!

  7. Waterwelldude

    Waterwelldude Well driller,pump repair. and septic installer

    Messages:
    303
    Location:
    Texas
    The ground wire on the pump must continue the earth ground from the incoming power. Anytime the pump is replaced that does not have the ground wire, the cable is supposed to be changed to wire with the ground wire on it. That ground wire does not ground to the casing. But why someone would ground PVC just makes no sense at all.

    Alot of older pump did not come with this wire or connection. All the new ones do. If an older pump is changed the wire is supposed to be changed also to comply with the code or rules.

    Even with the ground wire coming form the pump going to a ground rod, sometimes that still will not stop the electolosys. When a ground wire, goes from the drop pipe to a ground rod. It will stop it.


    Travis
  8. Rutherfordman

    Rutherfordman DIY Member

    Messages:
    46
    Location:
    North Carolina
    Thanks everyone,
    Now that I think about it the lightning protection guys are the ones who grounded the PVC casing. Hmmmm you would think they would know better. The pump house is aways from the house and I have a ground rod farm for the house pane due to lightning. Evidently from what I was told poorly grounded panels actually attrack lightning. In talking with an electrician who lives in a similar location he recommended putting ground rods down around all 4 corners of the pump house and connecting all of them together to intercept stray current from lightning. I have done that too but the drop pipe is not grounded. I will definitely do this. Yall have been alot help. Appreciate your time.
  9. valveman

    valveman Moderator Staff Member

    Messages:
    4,469
    Location:
    Lubbock, Texas
    I always wrap the pipe connections at the pump with electric tape. This stops any corrosion at the exposed threads, especially when switching from a brass or stainless check valve or pump to steel pipe. This nearly always happens at the exposed pipe threads just above the pump. In your case I would also wrap the other couplings that are under water, and about 6" below and above the threads. When you pull this tape off in 30 years, the pipe and fittings underneath still looks brand new.
  10. Gary Slusser

    Gary Slusser That's all folks!

    I can't believe that the yard has to be dug up to add a ground wire when a 2 wire pump is replaced. I suspect they are grandfathered instead, so I'd have to see the regs on that.
  11. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,248
    Location:
    Land of Cheese
    The NEC states that equipment must be installed per the equipment manufacturer's instruction. The pump manufacturer's have added a ground wire to the pump to meet UL requirements. I doubt the pumps instructions say that it's ok to NOT use it, therefore the ground wire back to the panel does need to be installed to meet the NEC requirement.
  12. Gary Slusser

    Gary Slusser That's all folks!

    Codes usually do not go backward, meaning that if this ground wire was not required at the time the well/pump was installed, it is "grandfathered" as meeting code, even if you replace the 2 wire pump, drop pipe and cable. If I replaced cable I put 2 wire with ground. New construction, it must meet this new code meaning the pump must be grounded all the back to the panel box, and to the metal casing.
  13. Rutherfordman

    Rutherfordman DIY Member

    Messages:
    46
    Location:
    North Carolina
    Are the threads on 1-1/4"galvanized drop pipe not galvanized? The pipe has a marking which says schedule 40 ERW and is galvanized pipe I believe. The threads seem to be where the worse corrosion is so wrapping them or protecting them would really help.
  14. sammyhydro11

    sammyhydro11 Previous member

    Messages:
    709
    Location:
    Massachusetts
    You might want to call a local licensed electrician regarding codes. They can give you a definitive answer on this. Whenever we replace a pump that has no ground wire, we replace the wire so it has the ground, and suggest to the homeowner that the line coming to the well is upgraded so everything is grounded properly.

    sammy

    www.tylerwellandpump.com
  15. Waterwelldude

    Waterwelldude Well driller,pump repair. and septic installer

    Messages:
    303
    Location:
    Texas

    This is exactly what you are supposed to do.




    There is no such thing as grandfathered, when it comes to up dating or changing the well pump, be it 2 wire or 3 wire.


    Travis
  16. Gary Slusser

    Gary Slusser That's all folks!

    Yes I also discussed the running of new cable from the switch to the casing with the customer. And I've already said if I changed the drop cable, I used 2 wire with ground.

    Rather than calling an electrician, I mentioned to the customer that they can call their local codes enforcement office and ask what code they are under, if any.

    Many locations won't be under the latest NEC code and may not be for 20 years, and if not, the customer doesn't have to replace or add to their present switch to casing cable. Or go to a new drop cable with ground unless there was something wrong with the cable. That and more was all discussed on the phone before I went out on a no water call. That's full disclosure and customers appreciate it.
  17. sammyhydro11

    sammyhydro11 Previous member

    Messages:
    709
    Location:
    Massachusetts
  18. Gary Slusser

    Gary Slusser That's all folks!

    Sammy, I said: Yes I also discussed .... and then I said; That and more was all discussed on the phone before I went out on a no water call. That is past tense.

    But yes we live full time and totally off grid in our motorhome. We are currently in SW AZ in the desert in teeshirts with the heat off and a window open at 9:30 pm. Someday when yer big... if you survive the depression.
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