Keith,
I think if you search the archives you will find a bunch of information on this subject. The general consensus, I believe, was to not try to back feed a generator. Make your point of interconnection ahead of the generator transfer switch. Often this means a supply side connection is easier if the home is already wired for a whole house generator. I seriously doubt you will have a big impact on fuel consumption, even if you are able to run the PV system and generator in parallel operation. The PV to generator size ratio would need to be sufficiently small for this to work. You certainly don't want to attempt to operate a 10kW inverter output in parallel with a 5kW generator, for example. If I understand it right, the generator would overspeed and the inverter(s) would lose sync. Anyway, if you don't want to replace expensive generator control boards if it doesn't work, just isolate the systems altogether. I've never tried it... too chicken, or maybe too smart... J Jason Szumlanski Fafco Solar From: [email protected] [mailto:[email protected]] On Behalf Of Keith Cronin Sent: Wednesday, July 20, 2011 3:05 PM To: RE-Wrenches Subject: [RE-wrenches] Generator-Transfer Switch-Solar Wrenches With the advent of micros on the scene and the potential for using a generator on an on-grid property, are any of you using a transfer switch to isolate the genny and use the PV to feed the genny to reduce fuel consumption? Are there issues with frequency and voltage? How are the utilities looking at these types of installations? Favorable? Would you use 2 transfer switches- one ahead of the other- to completely isolate the property or circuit panel to ensure there is no chance of a backfeed? Is it just better to keep things isolated as two separate systems? Regards, Keith
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