Generac 100 Amp Automatic Transfer Switch — SE Rated Service-Entrance, Whole-Home Backup with Smart AC Module

The Generac 100 Amp Legacy Automatic Generator Transfer Switch (RXSW100A3) automatically senses outages and transfers your entire 100A service to a compatible Generac standby generator for whole-home backup.

This service-entrance-rated transfer switch is built to connect a Generac home standby generator with an Evolution or Nexus controller to your main electrical panel, enabling fully automatic whole-house power switching up to 100 amps. It replaces manual interlock arrangements by starting the generator and moving the entire panel onto generator power when utility service fails, then reversing the process when utility power returns.

How does this switch protect my home and utility workers?

The unit uses an open-transition mechanical transfer method that never ties utility and generator power together, preventing backfeed into the grid. That isolation protects line crews and keeps your home wiring from being energized unexpectedly during an outage or restoration.

• Open-transition contactor prevents simultaneous connection of utility and generator.
• Service-entrance rating means it functions as your main disconnect under load.
• Powder-coated NEMA 3R aluminum housing resists corrosion outdoors or in garages.
• Requires a licensed electrician and permits for safe, code-compliant installation.

What electrical load can it handle for whole-home backup?

This 100-amp switch supports your entire 120V and 240V panel, allowing up to roughly 24,000 watts of generator supply depending on the generator model and configuration. It enables backup of major 240V appliances and central HVAC loads when paired with an appropriately sized Generac standby generator.

• Rated for full 100A service—covers whole-panel loads versus limited 30A or 50A manual options.
• Compatible with Generac standby generators using a floating neutral design.
• Actual supported wattage and run time depend on the chosen generator and its fuel.
• Not intended for portable generators or units with bonded neutrals from other brands.

Does this switch manage air conditioning and multiple large loads?

Yes—the RXSW100A3 includes a built-in Smart AC Module that sequences up to four HVAC loads so your generator can handle cycling high-demand equipment efficiently. If you need additional load management, Generac's optional Smart Management Modules expand controlled circuits without rewiring the main transfer switch.

• Built-in Smart AC Module sequences up to four HVAC systems automatically.
• Optional Smart Management Modules let you add staged control for more circuits.
• Load sequencing optimizes generator capacity and reduces peak strain.
• No extra hardware required for basic HVAC sequencing; extras are modular as needs grow.

What should I know about installation and compatibility?

Because this device serves as the service disconnect for your home, local electrical codes typically require a licensed electrician and permit for installation. Confirm your generator model uses a floating neutral and an Evolution or Nexus controller before ordering to ensure compatibility.

• Installation by a licensed electrician is required; this is not a DIY product.
• Designed specifically for Generac standby generators with Evolution or Nexus controls.
• Does not include generator, inlet box, or cord; those are sold separately.
• Allow roughly 20 inches height and 15 inches width clearance beside your main panel.

Who is this for? The Generac 100 Amp Legacy Automatic Transfer Switch is for homeowners who want fully automatic, whole-house standby power using a compatible Generac standby generator. It suits properties that require backup of large 240V loads—like central HVAC, well pumps, and dryers—and for anyone who prefers an automated, code-compliant transfer solution managed by a licensed electrician rather than manually switching circuits during outages.