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Manual Transfer Switch sizing

PV2EV

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With 30A working for the Lightning, does it make sense to oversize a Manual Transfer Switch (say 50A) for a future proof install? If so, what do I do for the outlet/truck connection?

Reading posts about the beta state of HIS (docs at least), and the need to free-up circuits for the FCSP 100A breaker, I am leaning to a transfer switch with a generator connection instead.

With a 400A main service on my house, 5 subpanels in 2 buildings, and my solar PV and inverters on my south facing barn, the HIS likely will not work for me. Optimally in future I could buy a 10kW or 24kW PV inverter that would keep the PV up when the grid down, treat the truck like a static battery, and remote disconnect the grid at the mains.
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FlasherZ

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I responded in your other thread but didn't address the generator inlet. I'd just install a 30A inlet for now, even if you upsize the ATS.

My setup is very similar to yours... I have 320/400 service. Meter has 3 sets of lugs for 3 different service panels, first service panel is the 200A ATS with all the standby loads; second service panel is a grid-only 200A panel with the feeders to the hot tub, pool house, machine shed, and EV charger #1 subpanels; third service panel is a 100A service disconnect with a feeder to EV charger #2 subpanel and FCSP. I have 18 kW of solar PV scattered across buildings.

I don't anticipate doing any V2H stuff, only because I'd be doing a lot of work to move things around for limited value.
 
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PV2EV

PV2EV

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Similar issues 🤷‍♂️ The options I have with the HIS (10kW version I am trying to get) suck:

1. Mount it all in the garage for the 200A panel there, and run the DC wires for 10kW of PV through the one remaining 2" conduit from the barn. Don't have clue how much wire this is, but doubt 2" is enough, not to mention the 80' distance.

2. Mount it in the barn and run the 200A service going to the garage, to the MID in the barn. Issue is I don't have enough conduit to return the power from the MID to the garage sub-panel (doubling the. conductors/fill).

3. Maybe install the MID in the garage for the house loads, and the BDI & FCSP in the barn for the PV. Then I would only need to run whatever (not sure per attached diagram) is needed between them in the conduit? Issue here is if the PV stays up, I am backfeeding the grid from the barn panel. If the PV is not up, all I am done is gone from 30A Gen input to 40A MID for big$

I looks like I will need to wait for a solution that works with the truck, and can disconnect @ the meter and feed the garage panel from the barn panel via the meter panel/breaker bus.

Ford F-150 Lightning Manual Transfer Switch sizing HIS Diagram
 


 


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