Generac RTSW300A3 300A 1ph-120/240V Service Rated Nema 3R Automatic Transfer Switch

Generac RTSW300A3 300A Automatic Transfer Switch Features:

The Generac RTSW300A3 300A Automatic Transfer Switch is built for whole-house protection where demand is heavy and reliability is critical. Service-rated and capable of handling up to 300 amps, this switch can act as the main disconnect—simplifying installation and ensuring your setup meets code in many jurisdictions. It’s designed to work with single-phase standby generator systems (120/240V), delivering safe, automatic power transfer when the grid fails.

What makes the RTSW300A3 smarter is its built-in load-management functionality. Without needing extra hardware, it can handle up to four HVAC circuits (24 VAC controlled), allowing the switch to prioritize essential loads and reduce the size (and cost) of the generator you need. For homes with additional large loads, there’s also expansion capability via Smart Management Modules (SMMs) to extend load control further.

Rugged construction ensures durable performance: the enclosure is NEMA 3R rated aluminum, making it suitable for outdoor or sheltered indoor mounting. Internal components—including the contactor and lugs—are built for frequent use and high electrical stress. It includes code-friendly features like service disconnect capability, open-transition switching (so utility is fully disconnected before generator supplies power), and a 5-year limited warranty to backup long-term reliability.

Key Features

• 300 Amp service-rated automatic transfer switch for single-phase, 120/240V systems

• Service entrance rated—can serve as the main disconnect where electrical code allows

• Built-in load management: controls up to 4 HVAC loads without extra hardware; expandable via Smart Management Modules for more loads

• Open-transition switching: utility load is disconnected before generator supplies power

• NEMA 3R aluminum enclosure, suitable for outdoor or indoor application; powder coated for corrosion resistance

• Heavy-duty contactor and properly sized lugs to handle high current loads

• Compatible with Generac standby generator controllers (Evolution™ or Nexus™) for integrated timing and sensing control

• UL/ETL listed for safety and performance

• 5-year limited warranty