Announcement

Collapse
No announcement yet.

Hot Water Heater Breaker/Disconnect Size for Commercial Space

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Hot Water Heater Breaker/Disconnect Size for Commercial Space

    The incoming service is 120/208V/3P.
    The Hot Water Heater says it's Input KW is 40.5kW-120/208V/3P

    So please let me know if I am doing the path correctly

    40500/1.73*208 = 112.42 Amp
    112.42*125% = 140.52 Amp

    So will I require a 150 AMP since a water heater of this type is required to be considered a continuous load meaning that the branch circuit needs to be calculated at 125% of the heater’s rated ampacity.

    #2
    That is one large water heater -- assuming all elements come on at one time 150 amps seems correct
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky

    Comment


      #3
      i think it's a Continuous Load if it's a Storage Tank WH. An Instantaneous WH (and to me, 40kw feels like it may be) is rated at 100%. Not 125%.
      IIRC

      Comment


        #4
        Originally posted by raberding View Post
        i think it's a Continuous Load if it's a Storage Tank WH. An Instantaneous WH (and to me, 40kw feels like it may be) is rated at 100%. Not 125%.
        IIRC
        Could you let me know what code section you found this in?

        Comment


          #5
          Originally posted by Electricalhelp View Post
          Could you let me know what code section you found this in?
          422.13
          If you aim at nothing, you will hit it every time!

          Comment


            #6
            Originally posted by raberding View Post
            i think it's a Continuous Load if it's a Storage Tank WH. An Instantaneous WH (and to me, 40kw feels like it may be) is rated at 100%. Not 125%.
            IIRC

            I have hooked up 3 phase water heater that was 100 amps so this could be a tank
            They say I shot a man named Gray and took his wife to Italy
            She inherited a million bucks and when she died it came to me
            I can't help it if I'm lucky

            Comment


              #7
              It's a 120 Gallon all Electric Hot Water Heater

              Comment


                #8
                125% it is then
                :-)

                Comment


                  #9
                  Originally posted by Electricalhelp View Post
                  It's a 120 Gallon all Electric Hot Water Heater
                  Seems unnecessary, if the water is hot why do you need a heater?
                  If you aim at nothing, you will hit it every time!

                  Comment


                    #10
                    Originally posted by Little Bill View Post
                    Seems unnecessary, if the water is hot why do you need a heater?
                    Maybe he needs hotter water?

                    Comment


                      #11
                      mebbe it's a

                      Heat Water Hotter Heater

                      Comment


                        #12
                        If it was 121 gallons you could eliminate the 25% from your calculation. I'm guessing that they stop at 120 gallons.
                        Rob

                        Moderator

                        All responses based on the 2014 NEC unless otherwise noted

                        Comment


                          #13
                          Originally posted by raberding View Post
                          mebbe it's a

                          Heat Water Hotter Heater
                          LOL
                          I like it.

                          Comment


                            #14
                            Originally posted by raberding View Post
                            mebbe it's a

                            Heat Water Hotter Heater
                            No, silly rabbit, that's a booster.
                            Master Electrician
                            Electrical Contractor
                            Richmond, VA

                            Comment


                              #15
                              Originally posted by LarryFine View Post
                              No, silly rabbit, that's a booster.
                              Anything that raises the temperature could be called a booster [emoji3]

                              Comment

                              Working...
                              X