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Running a generator during a power outage works well for basic household needs, but powering hardwired systems like a well pump or furnace requires a different approach. Many homeowners in remote or storm-prone areas face this challenge. You can solve it by installing a transfer switch for your portable generator.
In the video above, This Old House host Kevin O’Connor demonstrates how to install a transfer switch from start to finish. After watching, follow the step-by-step guide below to understand the process and gather the tools and materials you need.
Hiring a Professional vs. DIY for a Transfer Switch Installation
While installing a transfer switch can be a do-it-yourself (DIY) project, it can become dangerous. If you don’t have much experience with electrical work, we recommend hiring a professional. The right local electrician can work more safely and provide a higher caliber of work than an untrained DIY enthusiast, so it’s often worth the money to get it done right.
Understanding Transfer Switches
A transfer switch is a component that connects your portable generator to your home’s electrical system. It allows you to power essential circuits during an outage by simply flipping a switch.
Without a transfer switch, you’re forced to connect a generator directly to your circuit board, which can have catastrophic consequences. Dan Dunn, a power equipment expert featured in This Old House Magazine, warns that when utility power is restored while the generator is running, the two currents will collide violently. Such an electrical collision can burn out the generator or start a fire, dwarfing the damage of a mere blackout.
Types of Transfer Switches
There are two main types of transfer switches:
- Manual transfer switches: These require you to manually switch between utility and generator power.
- Automatic transfer switches: These detect power outages and automatically switch to generator power.
Preparing for Installation of Transfer Switches
Before starting the installation process, it’s important to gather the necessary materials.
Tools and Materials
To install a transfer switch, you’ll need:
- Circuit breakers
- Conduit and fittings
- Drill and bits
- Electrical cable
- Manual transfer switch kit
- Screwdrivers and pliers
- Voltage tester
- Wire strippers and cutters
Tip: Electrician Allan Gallant recommends adding the following tools and materials to your list for this job: a magnetic torpedo level for mounting the transfer switch plumb, a hacksaw for cutting conduit, a round file or reamer to remove burrs from freshly cut conduit, silicone caulk to seal the hole where wiring passes through your exterior wall, and galvanized decking screws for securing the electrical box to the wall.
Safety Precautions
Installing a transfer switch involves working with your home’s electrical system, which can be dangerous. Take these safety measures:
- Turn off the main power supply to your home.
- Use a voltage tester to make sure the wires aren’t active
- Use insulated tools and wear protective gear.
- Follow local electrical codes and obtain necessary permits.
- If you’re not comfortable with electrical work, hire a licensed electrician.
Transfer Switch for a Portable Generator Installation Steps
To install a transfer switch for a portable generator, follow the steps below:
- Mount the transfer switch to the wall beside the existing main electrical panel.
- Turn off the power to the house at the main electrical panel.
- Connect the wires coming from the transfer switch to the breakers in the main panel.
- From outside, drill a 1½-inch-diameter hole through the house wall.
- Screw the electrical box that comes with the transfer switch to the house wall directly over the hole.
- Run an electrical cable from the box to the transfer switch.
- At the outdoor box, connect the cable to the electrical receptacle that comes with the transfer switch.
- Screw the receptacle to the box.
- Move back inside and connect the receptacle cable to the transfer switch.
Testing and Operation of Your Portable Generator Transfer Switch
After installation, test the system and make sure it’s working correctly.
Initial Testing
- Start your portable generator outside, away from the house.
- Plug the generator into the inlet box.
- Simulate a power outage by turning your main circuit breaker off
- Switch the circuits on the transfer switch from “Line” to “Generator. “
- Verify that the selected circuits are receiving power.
Use the same steps to operate the generator during an actual power outage.
Portable Generator Safety Tips
Using a generator may seem pretty safe, but there are still some risks to consider. According to the Federal Emergency Management Agency, some common risks of using a generator are carbon monoxide poisoning, fire, and electrocution. Follow the safety tips below to make sure you don’t put yourself or your home in harm’s way.
Placement and Ventilation
Proper placement and ventilation can help prevent carbon monoxide poisoning:
- Outdoor use: Always operate the generator outdoors in a well-ventilated area.
- Distance: Keep the generator at least 20 feet away from your home, windows, and doors.
- Protection: Use a generator tent or cover to shield it from the elements while maintaining ventilation.
Tip: Consider purchasing a newer generator model with a built-in carbon monoxide sensor that automatically shuts the unit down if it detects dangerous carbon monoxide levels, adding an extra layer of protection.
Electrical Safety
Practicing electrical safety helps prevent accidents:
- Dry conditions: Operate the generator on a dry surface and avoid exposure to rain.
- Proper connections: Use heavy-duty, outdoor-rated extension cords that match your generator’s output.
- Avoid overloads: Do not exceed the generator’s rated capacity to prevent overheating and damage.
If you follow all the safety tips above, you can expect your generator to work safely and reliably.
Do you need help with home repairs? Consider a home warranty.
