[RE-wrenches] How to shed a load in a subpanel that is in a building other than where the solar system is interconnected

Christopher Warfel cwarfel at entech-engineering.com
Sat Aug 23 12:43:57 PDT 2025


Thank you, I did find their website and seeing if it has a chance.  Chris

On 8/22/2025 8:37 PM, Kirk Herander via RE-wrenches wrote:
> There is a company called Savant, I’ve seen their individual Smart 
> breakers installed in sqd Panels - they are individual smart breakers. 
> A single pole breaker would actually take up two slots one for the 
> OCPD itself, and one for the sp relay. Don’t know exactly how it 
> operates, but I know you don’t have to buy an entire smart panel for 
> it to work.
>
> As discussed on this forum, also, there are also RF transmitter/ 
> receivers, which can do what you ask. Used them to disconnect an 
> inverter from a common AC bus when the gennie turns on.
>
>
> *
> *
>
> *Kirk Herander / **kirkh at vermont.solar*
>
> *Owner|Principal, VT Solar, LLC*
>
> */Celebrating our 34^st  Anniversary 1991-2025!!/*
>
> dba Vermont Solar Engineering
>
> 802.559.1225
>
>
>
> On Fri, Aug 22, 2025 at 8:21 PM Chris Sparadeo via RE-wrenches 
> <re-wrenches at lists.re-wrenches.org> wrote:
>
>     Hi Chris,
>
>     I’m wondering if a load management device like this could be
>     helpful? However, it does not discern between grid presence and
>     island mode, so it might not fit the bill.
>
>     https://www.getstepwise.com/product?gad_source=1&gad_campaignid=22363404421&gclid=Cj0KCQjwqqDFBhDhARIsAIHTlkub687mJZYb6g0nIR33X1eA2FVY3bMc_zBxMr44IEl5a7QenVljhUgaArKeEALw_wcB
>     <https://www.getstepwise.com/product?gad_source=1&gad_campaignid=22363404421&gclid=Cj0KCQjwqqDFBhDhARIsAIHTlkub687mJZYb6g0nIR33X1eA2FVY3bMc_zBxMr44IEl5a7QenVljhUgaArKeEALw_wcB>
>
>     Quick caveat that shedding an HVAC unit potentially mid cycle is
>     not ideal for the health of that unit…but neither is an overload
>     and subsequent power failure.
>
>     I do know that Lumin Smart sells remote CTs for grid detection.
>     Might be worth a call to them to see if this fairly
>     inexpensive product can pair with a remote contactor to open the
>     HVAC circuit.
>
>     Best of luck!
>
>     -Chris
>
>     On Fri, Aug 22, 2025 at 3:54 PM Christopher Warfel via RE-wrenches
>     <re-wrenches at lists.re-wrenches.org> wrote:
>
>         We installed a 4kW Outback multimode system about 8 years
>         ago.  An
>         electrician came in afterwards and installed 3 heat pumps on
>         the battery
>         backed up power panels.  The Outback inverter disconnected on
>         load every
>         time there was a power outage. The electrician really messed
>         up and is
>         long gone. Also found out did not pull a permit. But I
>         digress.  We
>         managed to move two of the heat pump circuit breakers to the
>         utility
>         panel, so no longer on the battery backed up power panels. 
>         The third
>         heat pump is the problem as it is located in an apartment
>         building
>         remote from the main house. The whole apartment subpanel,
>         including the
>         heat pump load  is interconnected to the "main" battery backed
>         up power
>         panel in the home.
>
>         A master electrician and I are considering how to shed the
>         apartment
>         heat pump in a power outage.  We cannot easily run a separate
>         circuit to
>         the apartment building to pick up this load.  We have
>         considered a smart
>         panel, but the cost seems high for one circuit. Does anyone
>         know of a
>         power line product of RF product or similar that could operate
>         this
>         breaker when the main service panel loses power? I have been
>         unsuccessful over months of sporadic research.
>
>         Thanks in advance.
>
>
>         Chris
>
>
>
>
>
>
>
>
>         -- Christopher Warfel, PE ENTECH Engineering, Inc. PO Box 871,
>         Block
>         Island, RI 02807 (401) 447-5773
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-- 
Christopher Warfel, PE
ENTECH Engineering, Inc.
PO Box 871, Block Island, RI 02807
(401) 447-5773
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