What Should a Homeowner Ask About Gateways and Backup Panels?

In a Powerwall system, a gateway coordinates how the home, battery, solar equipment and utility connection interact, while a backup panel groups the circuits selected to remain available during an outage. Ask Solar Mike evaluates those components as part of the home’s complete electrical design, including support for 200A and 400A service panels .

The important question is not simply, “Does this proposal include a gateway?” It is, “What will this design actually back up, how will power be routed, and what assumptions were used?” Start with the broader guide to what whole-home backup means for a 200A or 400A Utah home before comparing equipment lists .

What does a gateway do in a Powerwall system?

A gateway is part of the control boundary between the home and the grid. In an outage-capable design, it helps the system recognize grid conditions, separate the protected electrical system from the utility connection when required, and coordinate available solar and battery power with the home’s selected loads.

That description is more useful than treating the gateway as an accessory. Its placement affects which electrical equipment sits inside the backed-up portion of the home. A proposal should therefore show where the gateway connects relative to the utility meter, main service equipment, solar equipment, battery equipment and any downstream panels.

Ask for a one-line diagram rather than relying only on a product list. The diagram should make the power path understandable to a homeowner: where utility power enters, where isolation occurs, which panel or panels remain energized during an outage, and which loads remain outside the backup boundary.

What does a backup panel do?

A backup panel is an electrical panel used to group the circuits selected for outage operation. Those circuits may include lighting, refrigeration, communications, selected receptacles or other loads chosen during design. Equipment outside that panel is not automatically part of the backed-up set.

The presence of a backup panel does not, by itself, tell you whether the proposed system is appropriate. You still need to know which circuits will be moved, whether any large loads will be excluded, and whether the selected battery configuration can support the intended operating plan.

Ask for a written circuit schedule. A useful schedule identifies each proposed backed-up circuit and any circuit intentionally left outside the backup panel. It should also distinguish between loads expected to run normally and loads that may require homeowner management during an outage.

Does every home need the same gateway and panel layout?

No. Electrical service size, panel arrangement, meter location, existing solar equipment, large loads and the homeowner’s outage priorities can change the architecture. Two homes with similar square footage can require different layouts because their electrical systems and desired backed-up loads are different.

Ask Solar Mike designs for both 200A and 400A service panels, but whether a specific home receives whole-home or essential-load backup—and the number and arrangement of gateways—is confirmed through site verification and engineering . Every system design is produced and reviewed by a licensed engineering firm .

For additional context about the relationship between service size and backup scope, review the Tesla Powerwall 3 whole-home backup guide for Utah .

What should the proposal show about the backup boundary?

The proposal should make the backup boundary visible. Do not settle for a general phrase such as “battery backup” without asking which equipment is on each side of that boundary.

• Utility connection: Where does grid power enter the home’s electrical system?
• Isolation point: Which device separates the protected system from the grid during an outage?
• Protected panels: Which panel or panels remain available after the grid connection is isolated?
• Excluded loads: Which circuits or equipment will not receive battery power?
• Solar relationship: How is the solar equipment connected relative to the protected electrical system?
• Battery relationship: Where does Powerwall connect, and which loads can request power from it?

If the proposal cannot answer those questions, request a revised diagram or written scope.

Which household loads deserve special attention?

Start with loads that can materially change the design or the homeowner’s outage strategy. Examples include central air conditioning, electric heat, electric water heating, EV charging, well pumps, pool equipment, workshops and multiple kitchens. The goal is not to assume that each load must be included or excluded. The goal is to identify it while the architecture is being developed.

For each large load, ask four questions:

1. Is this load inside or outside the proposed backup boundary?
2. Is it expected to start and run during an outage?
3. Will use of this load require another load to be turned off?
4. Is load-control equipment or a separate operating rule part of the design?

A clear answer prevents the phrase “whole-home backup” from doing more work than the electrical design. The practical scope should be shown by the diagram, circuit schedule and operating assumptions.

What should owners of 400A homes ask?

A 400A label does not describe the full panel arrangement. Ask whether the property has one main service assembly, multiple distribution panels, separate structures or other equipment that affects the backup boundary. Ask which panels are included and whether the proposal depends on more than one controlled connection point.

Ask Solar Mike can serve 400A homes, but the backup architecture must be confirmed at site verification rather than promised as a universal arrangement . The design should show how the proposed equipment relates to every panel that matters to the homeowner’s outage plan.

Which design documents should a homeowner request?

Request a package that allows the proposed scope to be checked without decoding sales language. At minimum, ask for:

• A one-line diagram showing the utility, gateway or isolation device, battery, solar equipment and protected panels.
• A circuit schedule identifying backed-up and excluded loads.
• A written explanation of how large loads are expected to operate during an outage.
• Any assumptions that depend on site verification or engineering review.
• A clear description of what could change after the electrical equipment is inspected.
• A change-order process for any material change in equipment, wiring or backup scope.

Ask Solar Mike provides a commissioning receipt, registration proof, monitoring handoff, homeowner ownership record, named escalation path and written change-order control after installation . Those records help connect the approved design to the system that was ultimately delivered.

Which questions clarify the proposed design?

Use this checklist during a proposal review:

1. What exact equipment is inside the backup boundary?
2. Which panels and circuits remain powered during an outage?
3. Which major loads are excluded?
4. Where is the gateway or other isolation equipment shown on the diagram?
5. Does the design cover one panel, multiple panels or a separate backup panel?
6. What assumptions still require site verification?
7. Who updates the design if the actual panel layout differs from the proposal?
8. What operating instructions will the homeowner receive?
9. What documentation confirms commissioning, registration and monitoring handoff?

The most useful answer is specific enough to compare with the final electrical design. If the response stays at the level of “everything should work,” ask for the circuit-level scope in writing.

What is the next step for comparing a proposed backup design?

Use the circuit checklist above, then continue with Ask Solar Mike’s guide to whole-home backup for 200A and 400A Utah homes .

Last reviewed: September 14, 2026 .
Reviewed by Mike Morris, Founder, Ask Solar Mike .