Voltage Drop Calculators

[Kornbread]

I am getting some wildly varying results when using online voltage drop calculators. This is going to make a large difference in the cost of the home run wiring. What online calculators have you found to be accurate? ... and a link please.

Best Boat Wire dot com



Bay Marine Supply

 

[sunshine_eggo]

Same answer on the one I always use:

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.

www.calculator.net

 

[Kornbread]

Ok,, I think I see what is going on. The Bay Marine calculator asks for round trip, while calculatordotnet asks for distance one way, and the Best Boat Wire calculator fails to specify either but appears to double the run length. Huge difference in $ wire.

For 92volts/60amps and 100' one way, and considering what the local Lowes has in stock, it looks like two runs of 6awg copper thhn/thwn(cheaper to buy a 500' roll for $325), or Aluminum URD 2-2-4 triplex for ~$120.

 

[再生可能 エネルギー]

I am getting some wildly varying results when using online voltage drop calculators.

Looking at Bay Marine Supply the caption says: "Length is the measurement of all wire used (ie: round trip)."

So if you enter '400 ft' instead of '200 ft' you will get for #6 (5.66%)
which is the same value than Best Boat Wire.com or Calculator.net

 

[Kornbread]

IIRC, somewhere there is an NEC code that says only wire gauge of 1/0 or larger can be paralleled. Does this apply to the home run from a ground based solar array, or is it ok to parallel 6awg? Since the home run wires from the array join at the solar inverter, aren't they in effect paralleled even if they start separately at the array?