Generac 400A Service Rated Aut...
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GENERAC RTSW400A3 RTSW400A3 - Smart Switch 400 Amp Service Rated 120/240 1Ø NEMA 3R

Generac 400A Service Rated Automatic Transfer Switch 120/240V 1� NEMA 3R with Digital Power Management

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Model: RTSW400A3
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Generac 400A Service Rated Automatic Transfer Switch 120/240V 1� NEMA 3R with Digital Power Management

Professional Automatic Power Transfer & Load Management

The Generac 400A Service Rated Automatic Transfer Switch delivers reliable backup power management for single-phase applications up to 48kW. Housed in a durable aluminum NEMA 3R enclosure with electrostatically applied powder coating, this UL listed transfer switch features Digital Power Technology (DPM) for advanced HVAC load control and Smart Management Module compatibility for comprehensive power management solutions.

Professional Features & Benefits

  • 400 Amp Service Rating: Handles substantial electrical loads for comprehensive backup power coverage in residential and light commercial applications.
  • Digital Power Technology (DPM): Manages up to 4 individual HVAC loads with 24 VAC control without additional hardware, optimizing generator capacity utilization.
  • NEMA 3R Aluminum Enclosure: Weather-resistant construction with powder-coated finish ensures reliable outdoor installation and long-term durability.
  • Heavy Duty Generac Contactor: UL recognized switching device engineered for years of dependable service and reliable load transfer operations.
  • Smart Management Module Compatible: Expands load management capability to 8 loads when used with Smart Management Modules for maximum installation efficiency.
  • Single-Phase 120/240V Design: Optimized for generators 60kW and below, providing versatile compatibility with residential and small commercial backup power systems.
  • UL Listed Certification: Meets rigorous safety and performance standards for professional electrical installations.

Technical Specifications

  • Amperage: 400 A
  • Assembled Weight: 130 lbs
  • Color Finish: Grey
  • Country Of Origin: United States
  • Department: Electrical
  • Installation Hardware Included: transfer switch
  • Installation Instructions Included: Yes
  • Manufacturer Warranty: 5 year limited
  • Material: Aluminum
  • Maximum Generator Input: 48000 W
  • Overall Depth: 17 in
  • Overall Height: 52 in
  • Overall Width: 25 in
  • Product Group: Power Distribution
  • Product Subgroup: Transfer Switch
  • Product Voltage: 120 V
  • Restrictions: No
  • Weight: 130 lbs

Installation & Operation

  1. Mount the unit in a suitable location with appropriate clearance and access for connections and service.
  2. Connect utility and load conductors following applicable guidelines and the manufacturer's instructions.
  3. Wire generator or power input according to the provided voltage/phase specifications and compatible capacity.
  4. Configure any available load management or control features as supported by the provided specifications.
  5. Test automatic transfer or operational functionality and verify proper performance before placing into service.
  6. Complete final inspection and follow ongoing maintenance practices appropriate to the product category.

Professional Applications

  • Residential Backup Power Systems
  • Small Commercial Facilities
  • Multi-Unit Properties
  • Professional Offices
  • Retail Establishments
  • Light Industrial Applications
  • Emergency Services Facilities

Smart Load Management Advantage

The integrated Digital Power Technology (DPM) provides intelligent HVAC load control capabilities, managing up to 4 individual 24 VAC controlled loads without additional hardware. When combined with Smart Management Modules, the system expands to manage up to 8 loads total, delivering the most installation-efficient power management options available for optimized generator utilization and seamless backup power operation.

Why Choose Generac Quality?

Generac delivers proven reliability with this UL listed transfer switch backed by a comprehensive 5-year limited warranty. The heavy-duty aluminum construction with NEMA 3R rating ensures dependable performance in demanding outdoor environments, while the precision-engineered contactor provides years of reliable service for critical backup power applications.

Manufacturer Resources

Product Specs

Amperage:
400 A
Assembled Weight:
130 lbs
Color Finish:
Grey
Country Of Origin:
United States
Installation Hardware Included:
transfer switch
Installation Instructions Included:
Yes
Manufacturer Warranty:
5 year limited
Maximum Generator Input:
48000 W
Overall Depth:
17 in
Overall Height:
52 in
Overall Width:
25 in
Restrictions:
No
Department:
Electrical
Product Group:
Power Distribution
Product Subgroup:
Transfer Switch
Product Voltage:
120 V
Product Material:
Aluminum
Product Weight:
130 lbs

Generac RTSW400A3 – Frequently Asked Questions

1) Will the Generac RTSW400A3 transfer switch work with my 48kW standby generator?
The RTSW400A3 accepts a maximum generator input of 48,000 W, so a 48kW single-phase unit is right at the top of its range. It's a 400 amp service rated switch built for 120/240V single-phase service. If your generator is larger than 48kW output, this isn't the switch for that set, and a three-phase or higher-rated switch is required instead.
2) Can the Generac 400 amp Smart Switch be mounted outdoors on an exterior wall?
Yes. The RTSW400A3 is housed in an aluminum NEMA 3R enclosure with a powder-coated grey finish, which is the rating for outdoor, rain-exposed mounting. Aluminum also means it won't rust the way painted steel does in coastal or wet climates.
3) How much wall space do I need for a Generac 400A automatic transfer switch?
Plan the wall for an enclosure measuring 52 inches high, 25 inches wide, and 17 inches deep, plus NEC working clearance in front for a service rated device. It's also a 130 lb unit, so the mounting surface and the crew need to handle that weight, and back-fastening into structure matters more than it would on a smaller residential switch.
4) Does a service rated transfer switch replace my main breaker panel's service disconnect?
Service rated is the key word on the RTSW400A3. A service rated switch contains the service disconnecting means, so it installs ahead of the panel and takes the place of a separate 400 amp main disconnect. A non-service-rated switch has to go downstream of an existing service disconnect. If you're feeding a whole 400 amp service from the meter, this is the configuration that does it in one enclosure.
5) How many air conditioners can the Generac Smart Switch shed without adding modules?
Built-in Digital Power Management handles up to 4 individual HVAC loads using 24 VAC control, with no extra hardware in the enclosure. That's four condensers shed and staged off a generator that couldn't otherwise carry them all at once. Add Smart Management Modules and the system manages up to 8 loads total.
6) Will the Generac RTSW400A3 work on 208V three-phase commercial service?
No. This switch is single-phase 120/240V only. Three-phase service needs a three-phase transfer switch. For multi-unit residential, professional offices, and light commercial on single-phase 120/240 service, the 400 amp rating here covers the whole service.
7) I have more than four large loads to manage on a generator. What do I add to the Generac RTSW400A3?
Smart Management Modules. The switch's own DPM covers 4 HVAC loads on 24 VAC control; SMMs extend load management to 8 loads total. The modules are ordered separately, one per additional managed load, and they let you shed non-HVAC loads like a well pump or range circuit that the built-in 24 VAC HVAC control doesn't reach.
8) Is load management on a transfer switch worth it, or should I just buy a bigger generator?
Load management is the cheaper path when the problem is simultaneous starts rather than total running load. The RTSW400A3's Digital Power Management staggers up to 4 HVAC loads so the generator never sees all the compressors inrush at once, which lets a 48kW or smaller set cover a house or small building that would otherwise need a larger machine. Where your steady-state running load genuinely exceeds the generator, shedding won't fix it and you need more kW. This switch tops out at 48,000 W generator input either way.
9) Is the Generac 400 amp Smart Switch UL listed for a permitted commercial install?
Yes, it's a UL listed transfer switch, with a UL recognized Generac contactor as the switching device. That's what an inspector looks for on a service rated installation.
10) What comes in the box with the Generac RTSW400A3, and what does my electrician still need to supply?
You get the transfer switch itself with installation instructions. Conductors, conduit, fittings, the generator control wiring, and any Smart Management Modules are separate. Model number to order against is RTSW400A3.
11) Are there shipping or sale restrictions on the Generac 400A automatic transfer switch?
None. The RTSW400A3 carries no restrictions, and it's manufactured in the United States, which matters if you're procuring against domestic-preference requirements on a government or institutional job.
How fast can I get the Generac RTSW400A3 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Generac RTSW400A3 come with a warranty?
Absolutely. The Generac RTSW400A3 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Generac RTSW400A3?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the Generac RTSW400A3 from ZenSupply?
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