Service Rated ATS with Remote Switch

[heimdm]

I am trying to design a solution for my customer. They have 400 amp service, that comes into the house via 2x 200 amp service disconnects. The utility has approved a line side tap for their solar installation. In order to add Tesla Powerwall, it gets complicated because of the 200 amp limitation. My current thought is that when the utility power goes off to have a service rated automatic transfer switch (outdoor rated), that way we can't back feed the grid. However, what I really need, is the ability to instead of routing the power from the solar to the grid, route it into the home. Is there any type of solution or ATS that has the ability to remote flip a circuit.

The idea is that in a utility power scenario, the connection between the "Patio MB MDP" and the 2x 200A Panels is closed. When utility power fails, the service disconnect would close, and the circuits between the "Patio MB MDP", and the 2x 200A would open.

 

[WildLeg 240]

You can use an ATS to do is, BUT with a grid tie system the inverters have a rapid shutdown to protect themselves and the electrical grid during an electrical outage. The inverters will not send out power unless they sense grid power. If you can over ride this function than you could use an ATS.

 

[heimdm]

The Tesla Gateway keeps the inverters online, and manages the Powerwall's (batteries). I have 2x 200amp sub-panels in the house, and the 200 amps that is connected via the line side tap. Since the service is rated for 400 amps, would I need a 400 amp ac disconnect after the meter to limit the current to 400 amps, since all the disconnects added together are 600 amps?

 

[jaggedben]

I am trying to design a solution for my customer. They have 400 amp service, that comes into the house via 2x 200 amp service disconnects. The utility has approved a line side tap for their solar installation. In order to add Tesla Powerwall, it gets complicated because of the 200 amp limitation. My current thought is that when the utility power goes off to have a service rated automatic transfer switch (outdoor rated), that way we can't back feed the grid. However, what I really need, is the ability to instead of routing the power from the solar to the grid, route it into the home. Is there any type of solution or ATS that has the ability to remote flip a circuit.

The idea is that in a utility power scenario, the connection between the "Patio MB MDP" and the 2x 200A Panels is closed. When utility power fails, the service disconnect would close, and the circuits between the "Patio MB MDP", and the 2x 200A would open.

I think it's hard to offer intelligible advice on this without a clearer description of the components and the customer's goals.

What is the solar system output and how many Powerwalls?
What '200A limitation' is at issue? The Tesla gateway?
Is it required to backup both existing 200A panels? Why not move critical loads from one to another? Or backup just one? Or, why not install separate backup systems? (i.e. two gateways?)

As far as an ATS that remotely or automatically flips a circuit, yes that is what an ATS does. You could put in an ATS for each 200A panel, that might be a solution. However, you'll have a problem that doesn't apply to the typical ATS setup with a generator, which is that the 'backup' supply will always be on when the normal 'grid' supply is on. You'll have to confirm that whatever ATS you use isn't confused by that. I imagine it's possible but i don't know enough about ATS products to advise.

 

[jaggedben]

You can use an ATS to do is, BUT with a grid tie system the inverters have a rapid shutdown to protect themselves and the electrical grid during an electrical outage. The inverters will not send out power unless they sense grid power. If you can over ride this function than you could use an ATS.

This is kind of off topic. Yes, in any system with backup power supplying AC voltage to the solar in an outage, you need a rapid shutdown disconnect that doesn't rely shutting down the grid power. But he would have to consider that issue regardless of the ATS. The two issues don't overlap.