[RE-wrenches] Interconnection with Generator

[Phil Forest]

Interconnecting the inverter output to the utility side of the transfer switch is not necessarily an absolute rule. A knowledgeable solar EE told me a few years back, that interconnection can be made on the load side if the inverter kW output is small compared to the generator kW, that large kW generators can produce clean AC power allowing the inverter to operate and to operate without risk of burning out the generator.  I don't remember what the inverter to generator ratio needs to be, or if other criteria needs to be met. 
Never tried it, we always connect to the utility side. 

Phil Forest
South Mountain Company

> On Oct 28, 2014, at 10:48 AM, Corey Shalanski <cshalanski at joule-energy.com> wrote:
> 
> Wrenches,
> 
> We frequently encounter residences with backup generators. The question that arises: how should the PV system be interconnected?
> 
> I have searched the archives and found some good information about this subject, but nothing definitive. I have fallen into the habit of broadly proclaiming that the PV system *must* be interconnected on the "utility" side of the transfer switch - in order to prevent backfeeding into the generator and thereby eliminate unintentional equipment damage. Is this concern justified? If so, should this be an absolute rule or would it depend on the generator make/model?
> 
> Thanks for any insights.
> 
> --
> Corey Shalanski
> Joule Energy
> New Orleans, LA
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