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Thread: Questions an above ground fuel tank

  1. #1
    Join Date
    Jun 2006
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    NoDak
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    339

    Questions an above ground fuel tank

    I don't have much experience with Class1 wiriring,

    I'm going to wiring the dispenser pump motor for a new 500 gallon above ground storage tank that will be used for gasoline. There's already 3 tanks there that are "diked". This additional one will use the same circuit that already feeds the other pumps.

    If I understand correctly, according to 514.3B, the shaded area in the drawing is C1D2?
    The power that I'll tap off of is located at the existing middle tank but slightly outside the C1D2 zone (~4foot off the ground and about 4 foot away from the tank). Am I understanding this correctly? So when I tap off that power supply my raceway will be entering inter a C1D2 zone and I'll need a seal off before entering that zone?

    When my raceway goes to the pump motor I'll need another seal off there also?
    I plan to use 1/2" rigid as my raceway.

    Also, the owner wants this tank operated with a key switch. Any recommendations about the "standard" or best way to accommodate this? I plan to call the supply house in the morning to see what they suggest. Should I do the key switch right at the tank dispenser or I can put the key switch where the power supply is that is just outside of the C1D2?

    Thanks for suggestions and input!

  2. #2
    Join Date
    Dec 2007
    Location
    NE Nebraska
    Posts
    37,962
    Quote Originally Posted by sw_ross View Post
    I don't have much experience with Class1 wiriring,

    I'm going to wiring the dispenser pump motor for a new 500 gallon above ground storage tank that will be used for gasoline. There's already 3 tanks there that are "diked". This additional one will use the same circuit that already feeds the other pumps.

    If I understand correctly, according to 514.3B, the shaded area in the drawing is C1D2?
    The power that I'll tap off of is located at the existing middle tank but slightly outside the C1D2 zone (~4foot off the ground and about 4 foot away from the tank). Am I understanding this correctly? So when I tap off that power supply my raceway will be entering inter a C1D2 zone and I'll need a seal off before entering that zone?

    When my raceway goes to the pump motor I'll need another seal off there also?
    I plan to use 1/2" rigid as my raceway.

    Also, the owner wants this tank operated with a key switch. Any recommendations about the "standard" or best way to accommodate this? I plan to call the supply house in the morning to see what they suggest. Should I do the key switch right at the tank dispenser or I can put the key switch where the power supply is that is just outside of the C1D2?

    Thanks for suggestions and input!
    What exactly are you going to tie into near the middle tank - Is it classified location rated? does it contain switches or overcurrent protection?

    Reason I ask is unless these are really large tanks you very well have an enclosure that is just barely outside the classified location and every raceway leaving it enters the classified location in one way or another - I would just treat it as though it were within the classified location, and I don't think there is anything wrong with that. If it doesn't contain any switches or other arc producing components - it wouldn't need to be explosion proof or have seals in the lines that connect to it. Any line that leaves and doesn't come back to the classified area would need a seal, as well as the other ends that connect to a pump or switch though.
    I live for today, I'm just a day behind.

  3. #3
    Join Date
    Jun 2006
    Location
    NoDak
    Posts
    339
    Yeah, it's definitely not classified location rated. It's a key switch that is mounted in a Midwest box (kinda hobble-fobbled together!).

    I was either thinking of mounting a key switch adjacent to it, stealing power off it, or just tapping power off of it and putting a key switch at the tank dispenser. Kinda depends on what the supply house has for key switch options.

    I know either way I'll have to use a seal-off when I leave that location and then again when I get to the tank dispenser, if I understand 501 & 514 correctly?

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