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    Gas station E stop

    I just had meeting with inspector and in it drawings said to install fuel panel F for petroleum gas station dispensers islands outside convience store.

    120/208V three phase Panel F feeds dispensers, pumps, signs and E stop buttons. The inspector then questioned why is Panel F feeder breaker feeding petroleum emergency stop buttons?

    I have no clue. The drawings showed Panel F feeding E stops that is required by NEC 2014 Article 514.11. Seems like their has to be something in between not just direct connection from120Vac fdr breaker to E stop buttons said the inspector.

    Again I have no clue what he meant.

    Following questions:

    1. How is gas station peteroleum E stop normally wired?

    2. Does anyone know or have any single lines or manufacturer recommended way as to why have Panel F feeder breaker feed E stop buttons?

    Thanks

    Sent from my SM-G935U using Tapatalk

    #2
    A quick browse online shows two schools of thoughts. First, e-stop passes power on activation to trip shunt trip breakers feeding the fuel pumps, etc. second is that e-stop passes power to contactors which power the pumps etc and that power drops out when e-stop activated. One point mentioned in my brief reading is that the contactor method is better since you’re more likely to know when there’s a problem with the e-stop system.

    Comment


      #3
      Originally posted by Stebs View Post
      A quick browse online shows two schools of thoughts. First, e-stop passes power on activation to trip shunt trip breakers feeding the fuel pumps, etc. second is that e-stop passes power to contactors which power the pumps etc and that power drops out when e-stop activated. One point mentioned in my brief reading is that the contactor method is better since you’re more likely to know when there’s a problem with the e-stop system.
      In your second method contactors do you have a dedicated singe pole feeder breaker in fuel panel 120V which just powers the E stop?

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        #4
        That would be my guess. If you fed the e-stop from something else’s breaker, and that device had a fault, you’d bring everything down with it when that breaker opened.

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          #5
          Originally posted by Stebs View Post
          That would be my guess. If you fed the e-stop from something else’s breaker, and that device had a fault, you’d bring everything down with it when that breaker opened.
          You nentioned online do you have link as to how they are wired? You also mention contactor method is reliable then shun trip. How is it exactly wired if not thru dedicated feeder breaker from fuel panel?

          Comment


            #6
            Originally posted by hhsting View Post
            In your second method contactors do you have a dedicated singe pole feeder breaker in fuel panel 120V which just powers the E stop?
            Why wouldn't the E-stop be part of the control circuit that controls all the pumps?

            Even if using shunt trip breakers it is pretty likely to power the shunt trip circuit from that same control circuit.

            That control circuit is part of the fuel pump system and if there is a panel dedicated to the fuel pumps and other related fuel equipment many would expect all controls to originate from that panel as well. Even lights illuminating dispensers or other accessory items related to the fuel equipment can sort of be expected to possibly originate from that panel.
            I live for today, I'm just a day behind.

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              #7
              If you are using a contactor, the E-stop circuit cannot come from the load side of the contactor (fuel panel) since the E-stop circuit needs power to send power to the fuel panel. The E-stop circuit must come from the line side of the contactor (with proper OCP) or from a circuit (dedicated) in the panel feeding the contactor.

              Do shunt trip breakers break the neutral?

              As far as the lights, I've heard it argued that if you have an emergency at night, you don't want to have the lights go out with the E-stop when you need to see what's going on, so ... ask someone before you wire it (like the fire marshal and building inspector).

              Comment


                #8
                Pay attention to 514.13

                That one is not caught be inspections usually, and can be a challenge to comply with. The controls guys were starting to push their boxes that will comply with this, they have it wired/configured that when you turn off the power to the dispenser, the dispenser communication, intercom, and video will also drop out.

                That's also something you need to think about with the E-stop, dropping out the intercom wiring.

                Like I said, a lot of inspectors didn't push this, but I quit doing these a couple of decades ago so ... things change.

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