There is a scenario where you are not using the Grid Sell feature where you can do what this diagram suggests. You can check the box for GEN on grid terminals and the two-wire start will still work.
If the grid fails, the generator does not start automatically. The transfer switch could be automatic or manual, but the generator only starts on command by the inverter, and no power is backfed (or no objectionable amount of power, to be more accurate). In a netmetering scenario, this wiring diagram can't work safely. Jason Szumlanski Principal Solar Designer | Florida Solar Design Group NABCEP Certified Solar Professional (PVIP) Florida State Certified Solar Contractor CVC56956 Florida Certified Electrical Contractor EC13013208 On Mon, Oct 19, 2026 at 11:58 PM [email protected] < [email protected]> wrote: > This schematic is right out of their installation manual so not some > science project here. I was flabbergasted but hoping to gain more info for > SolArk and this community. > > *Howard "Scot" Arey* > *Owner, Solar CenTex* > 254-300-1228 <(254)%20300-1228> > > ------------------------------ > *From:* RE-Wrenches <[email protected]> on behalf > of Sky Sims <[email protected]> > *Sent:* Monday, October 19, 2026 9:38 PM > *To:* List for professional installers of home-scale renewable energy > systems <[email protected]>; List for professional > installers of home-scale renewable energy systems < > [email protected]> > *Subject:* Re: [Re-wrenches] Sol-Ark for 400-amp service; help me > understand this whole-house generation diagram > > If that generator doesn’t put out clean enough power on initial start up, > and maintain a tight enough range dyring operation, the solark will likely > power cycle until they sync up. > Attempted a grid side connection of a Ford Lightning for a customer and > long time friend, to the grid inputs of his Solark dual 15kw with a 400amp > service. He wanted to do the experiment (and was willing to take the > financial risk’s involved, which I explained at length, spent two years > telling him no before finally saying ok about 3years ago), but that > frequency variance on startup is just too wide coming from the lightning > inverter and the tolerance is too narrow on the solark to reliably sync up. > In solarks defense it does keep trying and does sync up eventually but I > would not run this experiment again without an improvement In either > products capability to handle more frequency variance. The devil is in that > initial startup. Once synced up and under load the solark and lightning > inverter seem to get along well enough. But it’s jenky enough that I set > that option as emergency only configuration, the customer can enable the > sync if he chooses by flipping two levers. I have an automatic transfer > switch built in but I disabled the automatic switch until a more stable > option on startup presents itself. > In answer to another question that was asked, yes you can set what load > the solark will place the grid input generator under and what state of > charge the batteries need to be at to call for gen start. Just make sure > the start up frequency variance of the generator is tight enough to be well > inside what the solark requires. And remember sales reps may paint a better > picture of the frequency ranges than actually exist, so get it in writing. > > Sky Sims > Ecological Systems > > Sent with Spark <https://sparkmailapp.com/source?from=signature> > On Oct 19, 2026 at 9:43 PM -0400, [email protected], > wrote: > > > Can you AC couple the old fashion way, by back-feeding a breaker in the > protected loads panel, to save the generator input? > > Drake > > > > On 2026-10-19 19:31, Jay wrote: > > I agree why wouldn’t you install the generator at the Gen input? > > Ok if you’ve got a ac couple then that eats up the Gen input. > > But yeah brings up a lot of questions as to integration. > > Here is another. Does the sol ark know to reduce the charge rate if > the generator is not as big as the grid which I would expect? > > Makes the case for multiple sets of CT’s to measure and allow for > control. > > I’ll be curious what others think/know > Jay > > > > _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: [email protected] > > Change listserver email address & settings: > > https://lists.re-wrenches.org/mailman/options/re-wrenches_lists.re-wrenches.org/ > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/[email protected]/ > https://lists.re-wrenches.org/pipermail/re-wrenches_lists.re-wrenches.org/ > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > > > _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: [email protected] > > Change listserver email address & settings: > > https://lists.re-wrenches.org/mailman/options/re-wrenches_lists.re-wrenches.org/ > > There are two list archives for searching. 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