[RE-wrenches] Will IQ8 microinverters backfeed a generator during grid interruptions

[Christopher Warfel]

Gah, thank you.

On 1/22/2026 8:43 AM, scot.arey at solarcentex.com wrote:
> MI = microinverter
>
> *Howard "Scot" Arey*
> *Owner, Solar CenTex*
> 254-300-1228
>
> ------------------------------------------------------------------------
> *From:* RE-wrenches <re-wrenches-bounces at lists.re-wrenches.org> on 
> behalf of Christopher Warfel via RE-wrenches 
> <re-wrenches at lists.re-wrenches.org>
> *Sent:* Thursday, January 22, 2026 6:43 AM
> *To:* scot.arey--- via RE-wrenches <re-wrenches at lists.re-wrenches.org>
> *Cc:* Christopher Warfel <cwarfel at entech-engineering.com>
> *Subject:* Re: [RE-wrenches] Will IQ8 microinverters backfeed a 
> generator during grid interruptions
>
> Hi Scot, I am not familiar with the term MI, what does it mean?  Thank 
> you, Chris
>
>
>
> On 1/21/2026 12:07 PM, scot.arey--- via RE-wrenches wrote:
>> Good day,
>>
>> I many years ago watched the fast-switching capabilities of the IQ-8 
>> microinverters to produce only what demanded of the MI, and wondered 
>> if it might have application in a grid-tied system that is served by 
>> a whole-house generator.
>>
>> We have the opportunity to install grid-tied-only array of 24 IQ8 but 
>> all the MIs will be on the customer side of an auto-transfer switch 
>> and generator. We want to leverage using existing building wiring to 
>> carry the solar and all solar sizing meets the 120% rules.
>>
>> But I know that grid-tied solar on the customer load-side of the 
>> transfer switch means no place for full solar power production to 
>> flow to when the grid is not available...but then I thought back to 
>> that fast switching capability: is there a way to ensure the IQ8 
>> don't backfeed a generator when it is operating for a grid anomaly?
>>
>> I suspect the answer is "are you nuts???" but that video of 
>> capability got me thinking, "why not?" and if not, how is it - what 
>> tells the MI to cease production? - when it is within a full and 
>> proper ISC/ESS system design?
>>
>>
>>
>> *Howard "Scot" Arey*
>> *Owner, Solar CenTex*
>>
>> NABCEP PV Installation Professional
>> TECL 29755
>> 254-300-1228
>>
>>
>> _______________________________________________
>> List sponsored by Redwood Alliance
>>
>> Pay optional member dues here:http://re-wrenches.org <http://re-wrenches.org>
>>
>> List Address:RE-wrenches at lists.re-wrenches.org <mailto:RE-wrenches at lists.re-wrenches.org>
>>
>> Change listserver email address & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org <http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org>
>>
>> There are two list archives for searching. When one doesn't work, try the other:
>> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ <https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/>
>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org>
>>
>> List rules & etiquette:
>> http://www.re-wrenches.org/etiquette.htm <http://www.re-wrenches.org/etiquette.htm>
>>
>> Check out or update participant bios:
>> http://www.members.re-wrenches.org <http://www.members.re-wrenches.org>
>>
> -- 
> Christopher Warfel, PE
> ENTECH Engineering, Inc.
> PO Box 871, Block Island, RI 02807
> (401) 447-5773

-- 
Christopher Warfel, PE
ENTECH Engineering, Inc.
PO Box 871, Block Island, RI 02807
(401) 447-5773
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20260122/1654ce1e/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Outlook-cjrhro0j.png
Type: image/png
Size: 294949 bytes
Desc: not available
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20260122/1654ce1e/attachment-0001.png>