Electrial Requirements for Hot Water Heater

Discussion in 'Water Heater Forum, Tanks' started by safeire, Aug 28, 2011.

  1. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,838
    Location:
    NW Ontario, Canada
    Yes, the plot thickens...

    If one electrician declares the wire as undersized but the former electrician did not, there is an obvious difference of opinion. Code is code however and must be met for the sake of safety. Wire size could be a code issue if it is 30A breaker but wire size would not cause more current. Undersized wire can cause a voltage drop and subsequently higher current on impedance loads such as a motor but on a resistive load it would cause less current. This is evidenced by the rating plate that states that at 208V, it draws 4125 Watts and at 240V, it draws 5500 Watts.

    I think the electricians have some 'splainin to do.
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,285
    Location:
    Cave Creek, Arizona
    quote; It could be that the electrician that deemed the wire as needing to be replaced, also spec'd a larger breaker but the OP may have fixated on the highest cost part of the job, that being the running of a new line.

    Tru, but if "All he did was walk around the basement but never actually checked anything with any meters or other diagnostic tools", then that implies a superficial evaluation, and may NOT have anything to do with the real problem.
  3. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,838
    Location:
    NW Ontario, Canada
    This is true but let me play Devil's advocate. If I were a licensed electrician called to a job and found undersized wiring, I would first expect that the deficiency be brought up to code. In my work we have a responsibility called "Due Diligence" where I am obligated to point out serious deficiencies. If I fixed one thing and deliberately ignored an obvious deficiency which later caused harm, I could be held liable.

    If I were a mechanic and you took a car to me for a muffler and I saw that the car had no brakes, I would refuse to work on the car unless the brakes were included in the repair. If you had an accident as you left my shop with a new muffler and no brakes, I could land in court for failure to exercise due diligence.

    I'm not saying the electrician was right in calling out the wiring and purportedly leaving the impression that the wiring was the cause but if it is true that the wiring is undersized, under due diligence he can refuse to fix the cause for the tripping breaker if the wiring is not brought up to code.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,820
    Location:
    New England
    It all comes down to this: the WH will have a stated need for power, if the wiring AND CB are capable of supplying at least that amount, the system should work. If it doesn't, there's either a short somewhere or the CB or panel's bus are bad. It takes a lot of expensive equipment to really test a CB properly, and I doubt few, if any electricians actually have any on hand. If it is thought to be defective, often it's just a lot easier and cheaper to install a new one. Note though, that the CB could be fine, but if the bus it plugs into has problems, then it won't work reliably. If a new CB is installed where the bus is compromised, the new breaker could fail soon, too. Long periods of max current or slight overloads may not trip a breaker, but the heat cycling can create problems, weaken the spring contact, and cause it to fail. A bad bus (corroded, pitted, etc.) can prevent a CB from working properly. A CB often doesn't trip for awhile when the current is slightly over the rated value, but will trip immediately upon a direct short or where the current peaks rapidly. This is one reason why the equipment to test them can be expensive and not commonly available outside of a factory.
  5. safeire

    safeire New Member

    Messages:
    16
    Location:
    Ohio
    Thank you all for your responses. I contacted the original electrician with that question but have not heard anything back from him. I have called another electrician to assess. Based on everyone's feedback and my inspection based on those comments, I feel I need another opinion so that I actually fix the correct problem. I'm not intimidated by the cost, I just want to make sure the equipment is up to code and works properly so I don't have a fire or ruin the equipment.

    Once I have them out, I'll post the outcome.
    Safeire
  6. cwhyu2

    cwhyu2 Consultant

    Messages:
    1,331
    Location:
    Cincinnati OH
    Try an AMP meter to see what AMPs it is drawing.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,820
    Location:
    New England
    You still haven't indicated what gauge wire is feeding the WH. This is potentially the critical thing. The CB can only be as big as the wiring allows (although the CB can be smaller, it should never be larger than the wire can handle). The manual for the WH will state what size CB must be used to feed it.
  8. safeire

    safeire New Member

    Messages:
    16
    Location:
    Ohio


    UPDATE
    The second electrician was here today. He diagnosed two primary issues-he found that the plumber had some exposed wire around a cap when he opened the thermostat controls on top of the WH. Second, he replaced the existing 20/20 breaker with a 30/30 breaker. Everything is working perfectly now.

    The first professional who was here told me I needed to replace the wire and never tested anything on the WH or the panel. The second looked at the wire and said it was 10/3 and that it was sufficient. I'm glad to have had the feedback from everyone here. It really helped me understand all of the techbical terms to ask the right questions.

    Thanks to all who responded. I'm glad I had the second gentleman do the work rather than the first.

    Safeire

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