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calculating max. distance from source to load at 480V

calculating max. distance from source to load at 480V

calculating max. distance from source to load at 480V

(OP)
How far can you run a 480V line to power a single phase 1500W .8pf load? I don't remember my transmission line theory - anyone know how to calculate this?

K2ofKeyLargo

RE: calculating max. distance from source to load at 480V

That's only 4 amps at 480V single-phase (assuming you meant 480V and not 277V). If you make the wire big enough, you can run it a long way.  How far do you need to go and what kind of load is it?  

RE: calculating max. distance from source to load at 480V

(OP)
A contractor is planning on running it about 1 mile.  I don't know what the actual loading is yet - I don't have specs on the equipment yet, but it is a Dept. of Transportation camera and some microwave equipment to send the picture up the line back to headquaters - The power requirements I gave are just an estimate.

K2ofKeyLargo

RE: calculating max. distance from source to load at 480V

Using the voltage drop tables in the Cutler-Hammer Specifying Guide (because I'm lazy), 4 amps in a mile of #6 copper for a single phase load yields about 18 volts drop.  

RE: calculating max. distance from source to load at 480V

480V camera... :)

RE: calculating max. distance from source to load at 480V

(OP)
It is actually a 120V camera they say, but they think they can get 480V service run a mile then drop it down to 120V.  With an inductive load and AC current, the calculation is not just a simple resistance calculation, is it?

K2ofKeyLargo

RE: calculating max. distance from source to load at 480V

The enclose calculator could help you:      http://www.nexansenergy.com/egy/tecdoc/Corflex/index.html

To obtain the equivalent distance of 1 phase, 2wires, 480V, use the following trick:

System Type: 1 phase, 2 wires, 240V

Ampacity: 2 Amp 1/2 the Ampacity at 480V (1500W/480V~4A)

Power Factor: 80  %

Voltage drop limit: 3% or less

Distance: change it until desire results. Notice that the conductor size also change.

Imput other specific requirement, OH/UG, jacket, etc.

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