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Thread: 800 Amp Service

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    800 Amp Service

    I am going to figure Alu. conductors, would you run 2 pipes with #800 xhhw or more pipes / smaller wire. I had in my head #750 would work but looking at ampacities I don't think I can skip over the #800 when using the 800 or less exception. The service is 277/480 3 phase 800 amps.

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    Depending on specifics, I might run 4 250MCM. If I didn't need the full 800 I might go 3 350MCM.
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

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    If it satisfies your load you might even look at paralleling the 250s in (2) conduits, Likely it will be one size smaller conduit than your 800s and, possibly more readily available. and easier to work with..
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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    I would be safe with the #350. The load will not be close to the 750 amps they are good for.

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    Two sets of 750 kcmil Al is good for 770 (385*2) amps, next size up 800 amps. For copper 2 sets of 500 kcmil gets you 760 amps. Both scenarios in separate raceways.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

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    Quote Originally Posted by infinity View Post
    Two sets of 750 kcmil Al is good for 770 (385*2) amps, next size up 800 amps. For copper 2 sets of 500 kcmil gets you 760 amps. Both scenarios in separate raceways.
    Thanks I was looking at it wrong, wasn't doing a total like you.

    Thanks

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    Never asked a distributor or rep before...but can you get a CBer or Fus-SW with lugs for 800kCMIL.

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    Quote Originally Posted by MyCleveland View Post
    Never asked a distributor or rep before...but can you get a CBer or Fus-SW with lugs for 800kCMIL.
    Certainly not everything will have lugs for 750. One 800 A panelboard I did where I used 750 I had to specifically request 750 lugs
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

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    Quote Originally Posted by MyCleveland View Post
    Never asked a distributor or rep before...but can you get a CBer or Fus-SW with lugs for 800kCMIL.
    You always need to tell them what your cable size and quantities are going to be because the lugs are typically configurable when ordering.
    "Just because you're paranoid, doesn't mean they're not out to get you"

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    Quote Originally Posted by KWH View Post
    I am going to figure Alu. conductors, would you run 2 pipes with #800 xhhw or more pipes / smaller wire. I had in my head #750 would work but looking at ampacities I don't think I can skip over the #800 when using the 800 or less exception. The service is 277/480 3 phase 800 amps.
    Are you referring to 800 kcm? I didn't even know they made it that size. I can't imagine it being especially convenient or economical to use it. I would be inclined to parallel smaller conductors.

    I had to go look. it seems you can get XHHW in 1000 kcm as well. That is some big wire.
    Bob

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