Announcement

Collapse
No announcement yet.

Control circuit

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

    Control circuit

    I have existing relay contactor cabinet from which I have 2#14 AWG cable going to gas station Emergency stop switch.

    My questions are following:
    1. Is EGC required per code? If yes then what code section.
    2. How one sizes wire for such an application? It is currently sized #14 AWG.

    Thank you for your input

    Sent from my SM-G935U using Tapatalk

    #2
    Originally posted by hhsting View Post
    I have existing relay contactor cabinet from which I have 2#14 AWG cable going to gas station Emergency stop switch.

    My questions are following:
    1. Is EGC required per code? If yes then what code section.
    2. How one sizes wire for such an application? It is currently sized #14 AWG.

    Thank you for your input

    Sent from my SM-G935U using Tapatalk
    Have you researched this at all?

    What do you think is the answer?

    We do not know all the details you have left out.
    Tom
    TBLO

    Comment


      #3
      Originally posted by ptonsparky View Post
      Have you researched this at all?

      What do you think is the answer?

      We do not know all the details you have left out.
      I am not sure what the answer is nor which article to look in. I looked in NEC 2014 Article 514 but does not say anything about control circuit itself except distance E stop to dispenser and neutral is required to be opened . Its gas station emergency stop switch. Contactor is placed on feeder cables feeding fuel panel which is 120/208V single phase 60A.

      Thank you for your input.
      Sent from my SM-G935U using Tapatalk

      Comment


        #4
        For the EGC, start with section 250.122, I don't have a code book handy so thats as close as I can get.
        The wire is sized based on section 240.4 and article 310

        These are pretty basic questions, are you getting a permit and inspection?
        My concern is the work is at a gas station, work in classified locations and the risk involved.
        Moderator-Washington State
        Ancora Imparo

        Comment


          #5
          Originally posted by tom baker View Post
          For the EGC, start with section 250.122, I don't have a code book handy so thats as close as I can get.
          The wire is sized based on section 240.4 and article 310

          These are pretty basic questions, are you getting a permit and inspection?
          My concern is the work is at a gas station, work in classified locations and the risk involved.
          Yes there would be permit and inspection. Just have not dealt with contol circuit that much sizing and EGC.

          240.4 has power hazards, overcurrent devices rated 800A or less, overcurrent devices rated over 800A, small conductors, tap conductors, transformer secondary conductors, overcurrent protection for specfic conductor application.

          250.122 has general, increased in size, muliple circuits, motor circuits, flexible cord and fixture wire, conductors in parallel, feeder taps.

          None of them have control circuit except close is 240.4 overcurrent protection for specific conductor application but none for 250.122.

          Comment


            #6
            Originally posted by hhsting View Post
            Yes there would be permit and inspection. Just have not dealt with contol circuit that much sizing and EGC.

            240.4 has power hazards, overcurrent devices rated 800A or less, overcurrent devices rated over 800A, small conductors, tap conductors, transformer secondary conductors, overcurrent protection for specfic conductor application.

            250.122 has general, increased in size, muliple circuits, motor circuits, flexible cord and fixture wire, conductors in parallel, feeder taps.

            None of them have control circuit except close is 240.4 overcurrent protection for specific conductor application but none for 250.122.
            What is the size of the fuse that is in your control circuit?

            400 Amp fuse would require a #1 Cu EG. That doesn't sound like your install. You have to tell us. Typically a #14 would be protected at no more than 15 amps and even if its more, the EG is not required to be larger than the circuit conductors. 250.122(A). Continue reading on down to (F)(2). Is this circuit entirely in a nonmetallic raceway and boxes?

            Is your control 24vac? 120? IDK.
            Tom
            TBLO

            Comment


              #7
              Originally posted by ptonsparky View Post
              What is the size of the fuse that is in your control circuit?

              400 Amp fuse would require a #1 Cu EG. That doesn't sound like your install. You have to tell us. Typically a #14 would be protected at no more than 15 amps and even if its more, the EG is not required to be larger than the circuit conductors. 250.122(A). Continue reading on down to (F)(2). Is this circuit entirely in a nonmetallic raceway and boxes?

              Is your control 24vac? 120? IDK.
              Ok all I was given by the engineer is attached in sketch and in post #1. Voltage is low 24V and their is no overccurent protection from contactor to E stop. I understand this still may not be much.

              Sent from my SM-G935U using Tapatalk
              Last edited by hhsting; 07-30-19, 03:25 PM.

              Comment


                #8
                Originally posted by hhsting View Post
                Ok all I was given by the engineer is attached in sketch and in post #1. Voltage is low 24V and their is no overccurent protection from contactor to E stop. I understand this still may not be much.

                Sent from my SM-G935U using Tapatalk
                Also contactor and E stop are not located in classified hazardous location. E stop is on outside wall of convience store facing dispensers and contactor is inside the convience store along with Panel A and fuel Panel F

                Sent from my SM-G935U using Tapatalk

                Comment


                  #9
                  Is that contactor switching the neutral to the fuel panel also?

                  If there are any neutral requiring circuits out at the pump, and, your contactor is not switching the neutral conductor feeding the panel, then, all of the rules for fueling island shutdown are not being followed.

                  JAP>

                  Comment


                    #10
                    Originally posted by jap View Post
                    Is that contactor switching the neutral to the fuel panel also?

                    If there are any neutral requiring circuits out at the pump, and, your contactor is not switching the neutral conductor feeding the panel, then, all of the rules for fueling island shutdown are not being followed.

                    JAP>
                    Yes neutral is switched although question is about EGC required and sizing since no overcurrent protection and control circuit cable to E stop sizing.

                    Sent from my SM-G935U using Tapatalk
                    Last edited by hhsting; 07-30-19, 07:05 PM.

                    Comment


                      #11
                      Come to think of it I might have placed this thread in wrong section. Should it not go to Controls and PLC forum?

                      Sent from my SM-G935U using Tapatalk

                      Comment


                        #12
                        No one can help or provide input?

                        Sent from my SM-G935U using Tapatalk

                        Comment


                          #13
                          Originally posted by hhsting View Post
                          No one can help or provide input?

                          Sent from my SM-G935U using Tapatalk
                          Sounds like a portion of a circuit that falls under art 725 to me.

                          If it is 24 volts pretty good chance it is a class 2 circuit - likely could have used 18-2 thermostat cable for this circuit and no need for
                          EGC.
                          I live for today, I'm just a day behind.

                          Comment


                            #14
                            What is the 24v wiring method?
                            Master Electrician
                            Electrical Contractor
                            Richmond, VA

                            Comment


                              #15
                              Originally posted by kwired View Post
                              Sounds like a portion of a circuit that falls under art 725 to me.

                              If it is 24 volts pretty good chance it is a class 2 circuit - likely could have used 18-2 thermostat cable for this circuit and no need for
                              EGC.
                              What if you still provide EGC but not require is it extra safe or not recommended?

                              Sent from my SM-G935U using Tapatalk

                              Comment

                              Working...
                              X