Portable Generator Inlets with Interlocks: A Smart, Affordable Backup Power Option for Waukesha Homes

Power outages in southeastern Wisconsin aren’t a matter of if—they’re a matter of when. Between summer storms, heavy snow, ice, and high winds, losing power for hours (or even days) is something many Waukesha County homeowners experience at least once a year. When that happens, having a plan to keep the essentials running can make a stressful situation far more manageable.

One of the most practical and cost-effective solutions we recommend is installing a portable generator inlet with a mechanical interlock. This setup allows you to safely power key circuits in your home during an outage without the expense of a full whole-home generator system.

What Is a Portable Generator?

Portable generators are a flexible backup power option that can be powered by gasoline, propane, or natural gas. Many newer models are tri-fuel, meaning they can run on one or all three fuel types depending on availability. That flexibility is a big advantage during extended outages or fuel shortages.

Unlike whole-home standby generators, portable generators do not automatically turn on. They need to be started and connected manually. However, they typically cost a fraction of the price of an automatic generator installation while still providing reliable power for essential needs.

While a portable generator may not power every circuit in your electrical panel, it can comfortably run the most important loads, such as:

• Refrigerator and freezer

• Sump pump

• Furnace or boiler

• Select lighting circuits

• Wi-Fi, TVs, and small electronics

For most homeowners, that’s more than enough to get through an outage safely and comfortably.

Related: Looking for whole-home surge protection? Check out our full article on whole-home surge protectors here.

How a Portable Generator Inlet Works

Rather than running extension cords through doors or windows, we install a dedicated generator inlet box on the exterior of your home. This inlet uses a twist-lock connection, ensuring a secure and safe plug-in point for your generator.

The inlet is typically installed near the electrical meter and is rated for “in-use” conditions, meaning it keeps the electrical connection protected from rain, snow, and ice while operating. This is especially important in Wisconsin’s unpredictable weather.

When an outage occurs, you simply:

1. Move your portable generator outside to a safe location

2. Plug it into the exterior inlet using the proper generator cord

3. Start the generator

From there, power is safely delivered to your home's electrical system.

What Is a Mechanical Interlock—and Why It Matters

Inside your main electrical panel, we install a mechanical interlock device. This is a critical safety feature that physically prevents the generator breaker and the main utility breaker from being on at the same time.

Here’s how it works:

• When utility power goes out, you turn off the main breaker

• The interlock slides into position, allowing the generator (inlet) breaker to turn on

• This ensures power can only come from the generator—not the utility lines

This is extremely important for safety. It prevents backfeeding, which can cause serious injury to utility workers and damage electrical equipment.

When utility power is restored:

• The generator is shut off and unplugged

• The interlock slides back to its normal position

• The inlet breaker is blocked

• The main breaker can safely be turned back on

The system is simple, mechanical, and very reliable.

Related: Electrician tells all about whether you should use a fuse box or circuit breaker here.

How Big of a Generator Do You Need?

While every home is different, we generally recommend a 7,500-watt generator or larger for most residential applications. This size provides enough capacity to run multiple essential circuits without constantly worrying about overloads.

During installation, we can help you plan which circuits make the most sense to power during an outage, based on your home’s layout and priorities.

Why This Option Makes Sense

For many homeowners, a portable generator inlet with an interlock hits the sweet spot between cost, safety, and functionality:

• Significantly less expensive than whole-home generators

• No extension cords running through the house

• Few safety risks, code-compliant operation

• Flexible fuel options

• Reliable power for essential needs

If you want peace of mind during power outages without the investment of a standby generator, this is often the smartest solution.

Related: Do you have an electric vehicle? Learn more about how we can install an EV charging station at your home.

Professional Installation Matters

Generator inlets and interlocks must be installed correctly to meet electrical code requirements and ensure safe operation. As a local electrician serving Waukesha County, we at Home and Business Electric install these systems regularly and can walk you through your options from start to finish.

If you’re thinking ahead for the next outage, now is the time to prepare—before the lights go out.