[RE-wrenches] Parallel wire runs to increase size

[Jesse Dahl]

The NEC says you cannot parallel a wire smaller than 1/0. 

Portable PV may not fall within the NEC. 

The reason I mention it is that I was called to check an off grid system where the installer used and extension cord and paralleled all three #14s in the cord (blk,wht, and green).  Not a safe way to do things. 



Sent from my iPhone

On Feb 2, 2011, at 11:05 AM, Nick Soleil <nicksoleilsolar at yahoo.com> wrote:

> You shouldn't parallel wiring that way.  That is not acceptable by code, and it is unnecessary.   If the #10 is not sufficient just replace it.  Due to the fact that the larger wiring has much less resistance, most if not all of the current will flow on the larger wires.
>  
> Nick Soleil
> Project Manager
> Advanced Alternative Energy Solutions, LLC
> PO Box 657
> Petaluma, CA 94953
> Cell: 707-321-2937
> Office: 707-789-9537
> Fax: 707-769-9037
> 
> 
> From: "Starlight Solar, Larry Crutcher" <larry at starlightsolar.com>
> To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
> Sent: Wed, February 2, 2011 8:00:07 AM
> Subject: [RE-wrenches] Parallel wire runs to increase size
> 
> 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
> powered by STARLIGHT™
> 
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