Automatic Transfer Switches for Generators Your Ultimate Buying Guide

Why Generators with Automatic Transfer Switches Are Essential for Reliable Backup Power

Generators with automatic transfer switches provide the ultimate solution for seamless backup power during outages. If you’re looking to buy a complete system, here’s what you need to know:

Quick Answer: What You’re Looking For

• Complete System: A standby generator paired with an Automatic Transfer Switch (ATS) that monitors power 24/7
• Transfer Time: Power switches automatically in 10 seconds or less during an outage
• Key Components: The generator produces backup power while the ATS handles all switching automatically
• No Manual Action Required: The system starts, switches, and restores power without you lifting a finger
• Common Sizes: 100A, 200A, 400A, 600A, and 800A systems available for homes and facilities

Why This Matters

When the power goes out, you face more than just darkness. For homeowners, an outage can mean spoiled food, no air conditioning during a sweltering Florida summer, and disabled security systems. For a business, even a few minutes of downtime can halt production, disrupt operations, and lead to significant financial losses.

An Automatic Transfer Switch (ATS) is the brain that makes your generator truly automatic. It constantly monitors your utility power and, the moment it detects an outage, signals your generator to start. It then automatically transfers your electrical load to the generator, restoring power to your home or facility in about 10 seconds.

Without an ATS, you would need to manually start your generator and use a cumbersome, potentially unsafe manual transfer switch. With an ATS, the entire process is handled for you, whether you’re home, at work, or away. When utility power is restored, the ATS seamlessly switches you back to the grid and shuts down the generator, all without any intervention.

Find more about generators with automatic transfer switches:

• manual transfer switches
• generator parts and accessories
• generator transfer switch installation

What is an Automatic Transfer Switch and Why Do You Need One?

When the power goes out, you want the lights back on as quickly and safely as possible. That’s the job of an Automatic Transfer Switch (ATS). It’s the intelligent component in a standby power system that makes the transition from utility power to generator power seamless and automatic. For a neutral overview of how these devices work, see this summary of a transfer switch.

An ATS is the crucial link between your property’s electrical system, the utility grid, and your backup generator. It constantly monitors the incoming utility voltage. The moment it detects a power failure, it automatically starts your generator and transfers the electrical load to it. This entire process typically happens in 10 seconds or less, ensuring you have reliable backup power with minimal interruption. This provides not only convenience but also true peace of mind and safety.

The Automatic Transfer Process: Step-by-Step

Here’s a simplified look at how an ATS works to restore your power:

1. Power Failure Detection: The ATS continuously monitors the utility power. When it drops below a set threshold, it signals an outage.
2. Generator Start-Up: The ATS sends a signal to the generator, which starts automatically.
3. Power Stabilization: The generator runs for a few seconds to reach a stable operating voltage and frequency.
4. Load Transfer: The ATS switches your electrical system from the utility to the generator, restoring power to your home or business.
5. Monitoring Utility Power: While the generator is running, the ATS continues to monitor the utility lines.
6. Re-transfer Process: Once stable utility power returns, the ATS transfers the load back to the grid.
7. Generator Cool-Down & Shutdown: The ATS allows the generator to run for a brief cool-down period before automatically shutting it off, leaving it ready for the next outage.

Key Benefits of an Automated System

An automated backup power system offers significant advantages beyond just keeping the lights on.

• Hands-Free Operation: The system works automatically, 24/7. You don’t need to be home or do anything to restore power.
• Uninterrupted Power: Critical systems like air conditioning, refrigeration, security systems, and medical equipment continue to run without interruption.
• Appliance Protection: The ATS ensures a smooth transfer of power, protecting sensitive electronics and appliances from the surges that can occur with manual changeovers.
• Improved Safety: The most critical function of an ATS is preventing backfeeding—the dangerous flow of generator power back into utility lines. This protects utility workers and prevents damage to your generator.
• Reliability: Automated systems perform self-tests on a regular schedule, ensuring your generator is always ready to run when you need it most.

How to Choose the Right Automatic Transfer Switch

Alright, so you’re ready to accept the magic of generators with automatic transfer switches! That’s fantastic. But before you dive in, let’s talk about picking the right ATS for your specific needs. It’s a bit like choosing the perfect co-pilot for your generator – you want one that’s perfectly matched to your journey, ensuring smooth sailing no matter the weather. At MTS Power Products, we know that selecting the correct ATS is crucial for top performance, utmost safety, and staying compliant with all electrical codes. It’s definitely not a one-size-fits-all kind of deal, and there are a few important things to think about.

Sizing the ATS

First things first: we need to make sure your ATS is the right fit. This mostly comes down to its amperage rating. Think of it like this: your ATS’s amperage needs to be strong enough to handle all the power your home or business uses, and it also needs to match up with what your generator can put out.

• Amperage Rating: ATS units come in a wide range of sizes, like 50A, 100A, 150A, 200A, 300A, 400A, 600A, and even 800A. To figure out what’s right for you, we look at your total electrical load. If you’re aiming for whole-house backup – meaning everything stays on – your ATS amperage should generally match your main electrical panel’s breaker. If you just want to power essential circuits, your ATS might be sized to a smaller sub-panel that feeds only those critical areas.
• Voltage and Phase Type: Most homes, especially here in sunny Miami, FL, use what’s called single-phase power (think 120/240V). But for bigger commercial buildings or industrial sites, you often need three-phase power (like 208V or 480V). It’s super important that your ATS is perfectly compatible with your electrical service’s voltage and phase setup.
• Load Calculation: We always, always, always recommend having a qualified electrician – like the experts we can connect you with – do a thorough load calculation. This helps us pinpoint exactly which circuits are absolutely essential and what your total power demand will be. This way, we ensure your ATS and generator are a match made in heaven, working together flawlessly.

Service Entrance vs. Non-Service Entrance Rated

This might sound a bit technical, but it’s a really important distinction, especially for how your ATS gets installed and how it adheres to electrical codes, particularly if you’re looking for whole-house backup.

• Service Entrance Rated ATS: Imagine the point where electricity first enters your property from the utility company. A service-entrance-rated ATS is designed to be installed right there. It comes with a built-in main disconnect breaker, which is a big safety feature. For whole-house backup systems, this type is often a nationwide code requirement because it provides a clear, safe way to disconnect your entire property from the utility grid. It also simplifies installation by combining the main disconnect with the transfer switch.
• Non-Service Entrance Rated ATS: These switches don’t have that integrated main disconnect. They’re typically installed after your main service panel or even in a sub-panel. If you opt for a non-service-entrance-rated ATS for whole-house backup, you’ll need to have a separate main disconnect breaker installed upstream (closer to where the power comes in) to meet electrical codes. These are commonly used when you only want to back up a specific set of essential circuits, rather than your entire property.

Choosing the right type isn’t just about functionality; it’s about making sure your system is safe and follows all the rules set by the National Electrical Code (NEC) and local regulations right here in Miami, FL.

Understanding ATS Transition Types and Switching Mechanisms

Beyond just how big your ATS is, the way it actually switches power and the internal components it uses also vary. These differences can impact how your system performs and what it’s best suited for.

ATS Transition Types

This refers to the tiny moment when your power source changes over. It’s all about how gracefully that switch happens!

| Transition Type | Description

How to Choose the Right Automatic Transfer Switch

Selecting the perfect ATS for your generators with automatic transfer switches setup is a pivotal decision. It’s not just about getting “a switch”; it’s about getting the right switch that integrates with your generator and electrical needs.

Sizing the ATS

The size of your ATS, primarily its amperage rating, is paramount. This rating must be chosen to match your electrical service and generator capacity.

• Amperage Rating: Available from 50A to 800A+, the ATS must handle your electrical load. For whole-house backup, the ATS should match your main electrical panel’s rating (e.g., 200A). For essential circuits only, size to the sub-panel feeding those circuits.
• Voltage and Phase Type: Most homes use single-phase power (120/240V), while commercial and industrial sites often use three-phase power (208V or 480V). Your ATS must match your electrical service’s voltage and phase.
• Load Calculation: A professional load calculation is recommended to determine total power demand and essential circuits, ensuring your ATS and generator are sized correctly.

Service Entrance vs. Non-Service Entrance Rated

This affects installation and code compliance.

• Service-Entrance Rated ATS: Includes a main disconnect breaker and is installed where utility power enters the property. Often required by code for whole-house backup because it provides a single means of disconnect.
• Non-Service Entrance Rated ATS: Installed after the main service panel, typically feeding a sub-panel of essential circuits. If used for whole-house backup, a separate upstream main disconnect is required for code compliance.

Understanding ATS Transition Types and Switching Mechanisms

ATS Transition Types

Transition Type	Description
Open Transition	Break-before-make. Brief, acceptable interruption during transfer. Common for residential and many commercial systems.
Closed Transition	Make-before-break. No interruption; requires synchronization. Used in critical facilities; higher complexity and cost.

Switching Mechanisms

• Contactor Type: Heavy-duty relays. Robust, simple, and cost-effective; common in residential/light commercial units.
• Molded Case Type: Uses molded case breakers as switching elements, adding overcurrent protection; common in mid-range commercial and industrial applications.
• Power Frame Type: Uses large power circuit breakers for very high current applications with superior fault withstand ratings; typical in large industrial facilities and critical infrastructure.

Key Features to Look for in an ATS

• Load Management: Prioritizes essential loads and sheds non-essential ones to prevent generator overloads; can enable smaller, more cost-effective generators. Our McPherson Controls line offers advanced programmable controls and load management.
• NEMA Enclosure Rating: For outdoor installations (e.g., in Miami, FL), a NEMA 3R enclosure is essential for weather resistance.
• Remote Monitoring: View status and receive alerts from a smartphone or computer—standard in many McPherson Controls products from MTS Power Products.
• LCD Display: Provides real-time status, history, and diagnostics.
• Self-Testing: Programmable exercise cycles keep the system ready.
• UL 1008 Standard: Ensure the ATS is UL 1008 listed for safety and reliability.
• Surge Protection (SPD): Integrated SPD adds protection against power surges.

A Look at Popular Generators with Automatic Transfer Switches

When you’re shopping for generators with automatic transfer switches, you’re really looking at a complete backup power solution—not just individual parts. The key is finding a system where the generator and ATS work together seamlessly. At MTS Power Products, we specialize in exactly this kind of integration, offering professional-quality systems including our own McPherson Controls line, designed specifically for superior performance and safety in real-world conditions.

Key Factors for Choosing Generators with Automatic Transfer Switches

Matching your generator to your ATS is critical for a reliable system. Here are the key factors to consider:

• Generator Compatibility: Your ATS must be compatible with your generator’s voltage, phase, and control signals. It’s an essential first step for proper communication and function.

• Amperage Matching: Whether you need a 100A system for a smaller home, a 200A setup for a typical family house, or a larger 400A, 600A, or 800A system for a large property or business, your ATS must be rated for your electrical service and your generator’s output.

• Single-Phase vs. Three-Phase: Most homes in Miami, FL, use single-phase power, while commercial buildings often require three-phase systems. Your ATS and generator must both be designed for your property’s specific power type.

• Fuel Type: Your generator’s fuel source—natural gas, propane, or diesel—affects installation and operating costs. While the ATS doesn’t use fuel, its integration with the generator is part of the overall system design.

• Load Management: An ATS with intelligent load management can prioritize essential circuits and shed non-essential ones during an outage. This feature can allow you to use a smaller, more cost-effective generator while still keeping critical systems running.

Examples of Popular ATS Models

The market offers a wide range of automatic transfer switches. At MTS Power Products, we’re proud of our McPherson Controls line, which is designed with advanced features like remote monitoring, programmable displays, and robust safety standards to meet professional-grade requirements. Other manufacturers also offer quality solutions, including Generac’s automatic transfer switches, Kohler’s RXT series, and Briggs & Stratton’s Symphony II switches.

• Residential (100A-200A): These are typically open-transition switches, often service-entrance rated for whole-home backup. They provide reliable, automatic power for most households. Popular options include models from Generac, Kohler, and our McPherson Controls line.

• Mid-Range Commercial (200A-400A): These units often feature more advanced controllers, NEMA 3R enclosures for outdoor use, and may offer closed-transition options for businesses that cannot afford any power interruption. ASCO Power Technologies and Eaton offer competitive solutions in this range alongside our McPherson Controls products.

• Heavy-Duty Industrial (400A-800A+): Built for demanding environments, these systems use power frame switching mechanisms to handle massive electrical loads in facilities like hospitals, data centers, and manufacturing plants. Leading manufacturers include ASCO, Eaton, and our professional-grade McPherson Controls systems.

At MTS Power Products, our McPherson Controls line represents our commitment to providing professional-grade solutions customized to meet the exacting demands of our clients in Miami, FL, and worldwide. We engineer complete power solutions that integrate advanced monitoring, programmable controls, and superior safety features. Being centrally located near Miami International Airport and the Port of Miami, we can deliver these custom solutions wherever they are needed.

ATS Installation and Safety: What You Need to Know

When it comes to installing generators with automatic transfer switches, this is not a DIY project. An Automatic Transfer Switch (ATS) connects directly to your main electrical service, and improper installation can lead to fire, equipment damage, or severe injury. For the safety of your home, family, and utility workers, professional installation by a licensed and certified electrician is essential and often required by law.

The Installation Process

A professional installation ensures your system is safe, reliable, and compliant with all codes. The process generally includes:

1. Professional Assessment: An electrician evaluates your home’s electrical system to determine the correct size for the ATS and generator and identify the best location for installation.
2. Siting and Mounting: The ATS is mounted in a location that is accessible for maintenance and protected from the elements. Outdoor units in areas like Miami require a NEMA 3R rated enclosure for weather resistance.
3. Wiring: The electrician connects the ATS to your main electrical panel and the generator, establishing the power and communication lines necessary for automatic operation.
4. Grounding and Bonding: Proper grounding is critical for electrical safety, protecting your system from power surges and lightning.
5. System Testing: After installation, the entire system is thoroughly tested. This includes simulating a power outage to verify that the generator starts, the ATS transfers power correctly, and all components function as expected.

Following these steps ensures compliance with the National Electrical Code (NEC) and local regulations. Attempting to bypass professional installation can void warranties and create significant safety hazards.

How an ATS Ensures Safety and Reliability

An ATS is the core of a safe and dependable backup power system. Its design incorporates several key safety features:

• Prevents Backfeeding: This is the most critical safety function. The ATS creates a physical barrier that stops generator power from flowing back into utility lines, which could otherwise electrocute utility workers repairing the grid.
• Isolates Power Sources: It ensures that your home is connected to only one power source at a time—either the utility or the generator—preventing dangerous electrical conflicts and equipment damage.
• Protects Home Electronics: By managing the transfer of power, an ATS shields sensitive electronics and appliances from damaging power fluctuations.
• Ensures Reliable Operation: The automatic, self-acting nature of the switch means power is restored quickly and consistently, minimizing disruption. Many units are also UL Certified, meaning they meet strict, independent safety and performance standards.
• Reduces Fire Risk: Professional installation of an ATS eliminates the fire hazards associated with improper wiring and the unsafe use of extension cords often seen with portable generators.

With a professionally installed system from MTS Power Products, you are investing in unwavering safety and reliability for your home or business.

Frequently Asked Questions about Automatic Transfer Switches

We hear a lot of questions from folks in Miami, FL, and beyond about generators with automatic transfer switches. Let’s tackle some of the most common ones to help you feel confident about your backup power decisions.

Can I install an automatic transfer switch myself?

While it may be tempting to DIY, installing an ATS is a job for a licensed professional. It involves working with high-voltage electricity and requires a deep understanding of the National Electrical Code (NEC) and local regulations. An incorrect installation can lead to serious safety hazards, including electrical shock, fire, and dangerous backfeeding into the utility grid, which can endanger utility workers. It can also damage your equipment and void your warranties. For safety and compliance, always hire a certified electrician.

How do I know what size ATS I need?

Choosing the right size ATS is crucial for a reliable system. The size, rated in amps, depends on your electrical needs.

• Whole-House Backup: If you want to power your entire home, the ATS amperage should match your main electrical panel’s rating (e.g., a 200-amp service requires a 200-amp ATS).
• Essential Circuits Only: If you only need to power critical circuits (like refrigeration, lights, and medical equipment), the ATS can be sized for a smaller sub-panel that feeds those circuits.

A qualified electrician can perform a load calculation to determine your exact needs and recommend the right ATS and generator combination. At MTS Power Products, we can help you with this assessment to ensure your system is perfectly matched to your requirements.

How long does it take for an ATS to switch to generator power?

One of the biggest benefits of an automatic system is the speed of the transfer. In most cases, power is restored in 10 seconds or less.

When a power outage occurs, the ATS senses the loss of utility power and immediately signals the generator to start. Once the generator is running at the correct speed and voltage, the ATS safely disconnects from the utility line and switches your home’s electrical load to the generator. The entire process is so fast that you’ll barely notice the interruption.

Conclusion: Power Your Home with Confidence

Investing in generators with automatic transfer switches is more than just buying equipment; it’s an investment in security, comfort, and peace of mind. For homes and businesses in areas like Miami, FL, where power outages can be frequent, a reliable backup system is essential. An ATS is the key to making that system seamless and automatic, ensuring you have power when you need it most without any manual effort.

From selecting the right size and type to ensuring a safe, code-compliant installation, every step is critical. An ATS protects your property, your sensitive electronics, and the utility workers who keep our grid running.

At MTS Power Products, we are your direct source for professional-grade generators, automatic transfer switches, and our exclusive line of McPherson Controls. We specialize in creating customized, integrated systems that meet the highest standards of safety and performance. Located near the Miami International Airport and the Port of Miami, we are positioned to deliver reliable power solutions anywhere in the world.

Power your home or business with confidence. Let us help you find the perfect automatic transfer switch for your generator.