The Generac RTSW400A3 is a service‑rated automatic transfer switch designed for single‑phase standby generator systems operating at 120/240V. Rated for 400 amps, this switch can serve as the service entrance disconnect where permitted by local electrical codes, simplifying installation for larger residential or light commercial standby power systems. It is engineered to automatically transfer electrical load from utility power to generator power during an outage and return to utility power once normal voltage is restored, providing continuous power without manual intervention.

This transfer switch is well suited for whole‑home backup power applications that require high load capacity, including homes with multiple HVAC systems, large electrical panels, or significant connected loads. Integrated load management technology allows up to four HVAC loads to be managed directly without additional accessories, helping balance power demand during generator operation. Housed in a NEMA 3R aluminum enclosure, the RTSW400A3 supports both indoor and outdoor installations and is designed to protect internal components from environmental exposure. All timing, sensing, and transfer functions are managed by the compatible Generac generator controller to support reliable system coordination.

Service Entrance Rated

 Allows the transfer switch to function as the main electrical disconnect by safely interrupting utility power and enabling manual disconnection of a home or business from the electrical service.

Intelligent Load Management

 Supports control of up to four HVAC loads without additional hardware, improving system efficiency and helping reduce the generator size required for whole‑home backup power.

NEMA 3R Outdoor‑Rated Enclosure

 Supports indoor or outdoor installation while protecting internal switch components from rain, snow, ice, and debris.

Key Features:

• 400 amp service‑rated automatic transfer switch for single‑phase 120/240V systems
• Service entrance rated design allows use as the main disconnect where permitted by code
• Automatic operation transfers power between utility and generator sources without manual action
• Integrated load management supports control of up to four HVAC loads with no additional hardware
• NEMA 3R aluminum enclosure designed for indoor or outdoor installation
• Heavy‑duty Generac contactor engineered for long‑term service
• All timing, sensing, and transfer commands handled by the generator controller
• Backed by a 5‑year limited warranty