480V Light fixtures

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LarryFine said:
You left out a 1.73.

9600 / 480 / 1.73 = 11.56a


Like you would a 240v load on 240v. Two lines, no neutral.

I still think the delta method makes most sense, but nobody said anything about it.
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Ah i see! ok so to get the current on three phase system i divide by 1.73.

So that being said a 480V 3-pole 20A breaker would be plenty correct?

And my phase conductors would be 6AWG instead of 3AWG?
 
Allegiantelectrical said:
Ah i see! ok so to get the current on three phase system i divide by 1.73.

So that being said a 480V 3-pole 20A breaker would be plenty correct?

And my phase conductors would be 6AWG instead of 3AWG?
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Read my post #8 again. You do not need the largest wire all the way to the first pole.
 
Allegiantelectrical said:
First light is 473' away.. so i could technically run #10 to the first pole?
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I'm thinking run #10 between poles 3 and 4, #8 between poles 2 and 3, #6 between poles 1 and 2, and #8 from panel to pole 1 (the home run).

As you run from pole to pole, you reduce the load, so you don't need as much conductor to the next pole. And, the conduit can be reduced in size as well.

The other thing I'm suggesting is to run all three phases the whole way, as well as up each pole, dividing each pole's lights into thirds, and connecting them in delta fashion.

That would give you the most efficient and economical use of wires, only three, as well as the least voltage drop. You may only need #s 12, 10, 8, and 6 wire.
 
What I mean is, for the twelve lights on each pole, wire them into three groups of four lights.

One group between L1 and L2, one group between L2 and L3, and one group between L3 and L1.
 
there will be 8 lights on each pole, but could I run them like this?
Light 1. (4) lights on L1, (4) lights on L2
Light 2. (4) lights on L2, (4) lights on L3
Light 3. (4) lights on L1, (4) lights on L3
Light 4. (4) lights on L1, (4) Lights on L2
 
Allegiantelectrical said:
and i could just run #6 all the way to avoid having to buy a bunch of different wire sizes right?
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You could, but I wouldn't. The last pole in each run certainly doesn't need wire that large.

My thought is: "I can buy a bunch of different wire sizes to avoid running #6 all the way."
 
Allegiantelectrical said:
there will be 8 lights on each pole, but could I run them like this?
Light 1. (4) lights on L1, (4) lights on L2
Light 2. (4) lights on L2, (4) lights on L3
Light 3. (4) lights on L1, (4) lights on L3
Light 4. (4) lights on L1, (4) Lights on L2
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Remember, we're talking line-to-line loads, so each light would be connected to two lines.

You have 32 lights per run, almost divisible by three. I'm suggesting, for example:

Pole 1: (3) lights on L1-L2, (3) lights on L2-L3, and (2) lights on L3-L1
Pole 2: (3) lights on L1-L2, (2) lights on L2-L3, and (3) lights on L3-L1
Pole 3: (2) lights on L1-L2, (3) lights on L2-L3, and (3) lights on L3-L1
Pole 4: (3) lights on L1-L2, (3) lights on L2-L3, and (2) lights on L3-L1 (same as pole 1)

Total loads: L1-L2: (11) lights, L2-L3: (11) lights, L3-L1: (10) lights

And that's with a total of only three wires (plus EGC) per run.

I see no more efficient use of materials nor less voltage drop than that.
 
LarryFine said:
I may have missed it. Do you agree with me?

i thin the OP mentioned multiple 2-wire circuits.
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I agree. Delta is the way to go.
I would be inclined #6 to the pole bases and #12 up the pole to fixtures. I haven't done any of the math.
I would use the bigger conduit throughout just for the physical strength where it emerges. Then again, I would also sleeve it a couple feet up for better mower protection. Depends on limited or get it done budget.
 
Allegiantelectrical said:
there will be 8 lights on each pole, but could I run them like this?
Light 1. (4) lights on L1, (4) lights on L2
Light 2. (4) lights on L2, (4) lights on L3
Light 3. (4) lights on L1, (4) lights on L3
Light 4. (4) lights on L1, (4) Lights on L2
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8 lights on each pole does not balance evenly across all three phases. In order to balance the run to the first pole as much as possible you need to swap which phase has lesser load on it at three of the four poles. The fourth pole is going to match one other 3 poles for loading of each phase.
 
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