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

[Chris Sparadeo]

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

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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