Electrial Requirements for Hot Water Heater

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

  1. safeire

    safeire New Member

    Messages:
    16
    Location:
    Ohio
    I just had an electrician check out my hot water tank because it has flipped the breaker since it was first installed. This gentleman is telling me I need to have a new line put in between the hot water tank and the panel. All he did was walk around the basement but never actually checked anything with any meters or other diagnostic tools. He is highly rated on Angie's list but it seems odd that putting a new hot water tank that is the same size as what I had before would require additional power.

    I'm asking this question on this forum because I'm trying to confirm how much power is needed for my electric hot water tank. Ever since it was installed, it flips the breaker. I have 240 coming into the house and the tank is an 80 gallon tank which is the same as I had before. The label on the tank shows single phase 208V and single phase 240V.

    Is there a test that I can run or somewhere I can look up the power requirements myself? I don't want to spend the money to put in a new line if it isn't necessary.

    Thank you.
    Safeire
  2. nukeman

    nukeman Nuclear Engineer

    Messages:
    711
    Location:
    VA
    It should say on the WH what the requirements are. However, nearly all full size electric WH use a 30A 240v circuit with 10/2 wire (assuming copper). Look at your panel and see if the WH breaker is 30A (or whatever the plate on the WH says).

    Even if the breaker size is correct, you still might have the wrong size wire (hard to tell without being there).
  3. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Check the watts rating on the water heater. It will either be 4500 watts, which requires a 25 amp breaker, and usually a 30 will be used. Or it is 5500 watts which requires the 30 amp breaker. #10 wire would be ok for either, unless it is a very long run.

    Undersized wire, if that was the issue, might overheat, might cause the water heater to not heat up fast...but why would that trip a breaker???

    Personally, I don't put great faith in the "list". You need an electrician who will tell you why the breaker is popping. That will explain what needs to be done.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,325
    Location:
    New England
    CB do fail on occasion, too. If it is the proper size for the wiring and is sufficient for the WH, then you might pop in a new CB (best left to an electrician unless you are conversant with the proper safety standards). It could also be someone was sloppy when installing the thing, and the connection is shorted. This would certainly pop the breaker.
  5. safeire

    safeire New Member

    Messages:
    16
    Location:
    Ohio
    Thank you. The label says for the 208V, 4125 and for the 240V 5500.
  6. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    OK so you definitely should have a 30 amp breaker, #10 wire. Still don' t know why the breaker pops
  7. nukeman

    nukeman Nuclear Engineer

    Messages:
    711
    Location:
    VA
    Okay. Now let's check the breaker. Find the one for the WH and it will have a number on it (25, 30, etc.).

    It may be that the old WH had a smaller element and the thing is on a 25A breaker, although 30A breakers are typically installed for WHs. Your new WH would take a 30A breaker.

    After you check the breaker size, take a look at the wiring coming into the WH. If it is Romex (flat looking cable), it should have some numbers printed on it. Look for numbers such as 10/2, 10-2, 12/2, 12-2, etc. and see what it says. If you aren't sure, you could take a couple pics and post them up on here and we might be able to help you figure it out.

    If the breaker and wiring are both correct, then I would get someone (other than this guy) to come out and take a look. Maybe have him replace the breaker (if it is weak) and have him look the WH connections over and make sure something isn't shorting out.

    Although not as likely, it could also be a defect in the WH with a bad t-stat or element causing a short when that t-stat cycles on.
  8. BobL43

    BobL43 DIY Senior Member

    Messages:
    1,799
    Location:
    Long Island, NY
    Good post!
  9. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,185
    Location:
    NW Ontario, Canada
    If a qualified electrician sees a serious deficiency such as an undersized wire, there is not much point in up-sizing the breaker since it all has to be code compliant. There is no point in playing with meters or any diagnostic tools until the most expensive part of the deficiency is dealt with.

    So, who installed the new water heater and connected to a purportedly undersized wire?
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,267
    Location:
    Cave Creek, Arizona
    Find someone who knows what he is doing to check the breaker and wire size. The new heater has 5500 watt elements, but that would NOT have been the common one for your former heater. It would be unusual for the wires to the heater to be smaller than #10, even if a smaller breaker was installed.
  11. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Well here we are flapping our collective gums...and no response from the OP! Nobody has said his wires are undersized. Everyone says they need to be CHECKED. We unfortunately have no idea why the breaker trips....is it too small for the 5500 watt, is it worn out?????
  12. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,185
    Location:
    NW Ontario, Canada
    This is true. I at least used the term "purportedly" since the OP leaves us with very little detail, saying only that he will "need to have a new line put in between the hot water tank and the panel".
  13. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,267
    Location:
    Cave Creek, Arizona
    Undersizedl wires would NOT trip the breaker,but they could overheat. The breaker COULD be undersized, regardless of the wire's size.
  14. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,185
    Location:
    NW Ontario, Canada
    Agreed. Undersized wire however suggests that the former water heater was of a lesser wattage particularly if it was originally done to code. Smaller gauge wire could also mean a lower amperage breaker. If the wire really is undersized for the new heater, the qualifications of the installer needs to be called into question.

    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. We were not there to hear the prognosis so have only the hearsay of the OP. I would not convict the electrician of incompetence based on what is said.
    Last edited: Aug 29, 2011
  15. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    AGREED, but I would convict the OP of hit and run!
  16. nukeman

    nukeman Nuclear Engineer

    Messages:
    711
    Location:
    VA
  17. safeire

    safeire New Member

    Messages:
    16
    Location:
    Ohio
    Wow...not sure how I could be convicted of hit and run when I just posted the additional details yesterday morning and I cannot check my email from work. I will look at the wire as suggested and take a picture if needed. The installed was a licensed plumber and the electrician licensed and had high ratings on Angie's list. I'm not doing this as a DIYer. And, actually, the electrician's quote was for several electrical items, not just the WH, but replacing the line was the only thing he recommended. I found it odd that he never actually used any diagnostic tools at the breaker or at the WH. I did look at the breaker and it does show 30A.

    Thanks to everyone who responded.
    Safeire
  18. safeire

    safeire New Member

    Messages:
    16
    Location:
    Ohio
    Thank you, Nukeman, for the recommendations. I will take a look and see what I can find.
  19. safeire

    safeire New Member

    Messages:
    16
    Location:
    Ohio
    Thank you, LLigetfa, for your response. He is a licensed electrician with 35 years experience so my expectation was that he would do some testing to diagnose where the problem was coming from. But, if 35+ years (or really, any # of years since I'm not a licensed electrician) experience allows him to eyeball the problem, I guess that's good enough then. I'm just trying to do my due diligence so I don't waste my time or set my house on fire because I didn't do my homework.
  20. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    We appreciate your feedback! We want to know the answer almost as bad as you! Perhaps you could just ask the electrician: " is something wrong with my cable or breaker?" He should not be offended by a question like that

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