[RE-wrenches] Parallel wire runs to increase size

[Mick Abraham]

Hi, Larry~

If you convert from American AWG wire gauge sizes to "millimeters squared"
units...you can add the "mm squared" values together, then convert back to
AWG. Here's one conversion chart among many which are available:

http://www.engineeringtoolbox.com/awg-wire-gauge-d_731.html

When running wires in parallel as you describe, one cannot be assured that
the amperage will divide proportionally to the various wire sizes...because
the connection to one strand may be stronger/better than the connection to
another one.

The marine world has the ABYC; the RV world may have something similar...and
those organizations may frown on the parallel wiring practice. I wouldn't
lose much sleep over this, but I would consider sizing any overcurrent
protection for the smallest conductor.

Jolliness,

Mick Abraham, Proprietor
www.abrahamsolar.com

Voice: 970-731-4675


On Wed, Feb 2, 2011 at 9:00 AM, Starlight Solar, Larry Crutcher <
larry at starlightsolar.com> wrote:

>  Wrenches,
>
> Some of our business involves repairing poor PV solar installations on
> recreational vehicles. So often we wind up installing a roof junction box
> and running a second PV to controller wire and then replacing the controller
> to battery wire size. For instance, we may find a 10 gauge wire run to the
> controller. We then add #8, #6, #4 or even 2 gauge and parallel to the #10
> depending on power and distance of the run. My question: Is there a
> calculator or chart that will tell me what the combination of any two wire
> sizes equate to? example: #10 + #4 = X
>
> Thanks.
>
> Larry Crutcher
> Starlight Solar Power Systems <http://www.starlightsolar.com>
> *powered by STARLIGHT*™
>
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