[RE-wrenches] EGC vs GEC, separately derived system

[Jason Szumlanski]

We typically run a #6 combined EGC/GEC on all residential systems just to
keep it simple. The cost difference is typically negligible. We use
irreversible C-crimps to combine the wires in a roof mounted junction box.

*Jason Szumlanski*

*Fafco Solar*


On Wed, Nov 28, 2012 at 10:56 PM, mac Lewis <maclewis1 at gmail.com> wrote:

> Hello wrenches,
>
> What constitutes a separately derived system?  Would you consider a
> breaker tied enphase system a separately-derived system?  Suddenly,
> inspectors in our AHJ are considering all PV systems separately derived
> systems and thus requiring applying GEC sizing (as opposed to EGC sizing)
> from the inverter(s) to the tie in point.  This does not jive with my
> understanding.  Would like to hear other thoughts about this.
>
> Here is the definition of a separately derived system as per 2008 NEC
> Article 100 Definitions:
>
> *Separately Derived System*:  *A premises wiring system whose power is
> derived from a source of electric energy or equipment other than a service.
>  Such systems have no direct electrical connection, including a solidly
> connected grounded circuit conductor, to supply conductors originating in
> another system.*
>
> For your enphase systems do you size your ground from roof to the breaker
> panel as an EGC or a GEC?
>
>
> Thanks in advance for your thoughts.
>
> --
>
>
>
> Mac Lewis
>
> *
>
> "Yo solo sé que no sé nada." -Sócrates
> *
>
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