Generator Interlock Kit – Keeping You Safe When the Power’s Out

Summer brings with it the threat of powerful weather systems, from pop-up thunderstorms to hurricanes. These storms can bring heavy rains, high winds, and dangerous lightning—all of which can potentially knock out the power to your home.

Do you have a reliable backup power source? Like other Naples-area residents, you may have a portable generator to make sure you can comfortably ride out a power outage. But is your generator as safe as it could be? 

A generator interlock kit can help ensure that your critical appliances and equipment can function safely during a power outage, without the need to run multiple extension cords from around your house. 

What is a generator interlock kit?

Installing a generator interlock kit is an easy, affordable way to make sure your generator can safely power parts of your home and prevent dangerous situations when the power comes back on. 

If you have a generator, an interlock kit prevents the breaker that feeds the generator from turning on while the main breaker is on. 

A generator interlock kit works by adding an external mechanism to your breaker panel that allows either the main breaker or a designated load breaker to be turned on, but not both. In this case, the load breaker (or “backfeed” breaker) would be connected to the generator. 

How a generator interlock kit works

Under normal conditions, when the main breaker is on and functioning, utility power comes into the house, goes through the power meter, and into the breaker, where it is distributed to every circuit in the house and all the appliances. 

Generator interlock kits work by physically blocking either the main breaker or the generator backfeed breaker from switching on. When the main breaker is on, a plate or arm (depending on what type of kit you have and how your breakers are set up) blocks the backfeed breaker from turning on and vice versa when the generator is on. This prevents both breakers from operating at the same time. In the event of a power outage, you can use your generator safely, and when the power returns, the interlock kit prevents your main breaker from coming back online until you turn off the generator. 

If the main breaker and the backfeed breaker (feeding the generator) were to operate simultaneously, your generator could be damaged at the minimum, and backfeeding the main breaker could cause very dangerous conditions, including electrocution and fires. 

An alternative to a generator interlock kit is to install a dedicated transfer switch. This mechanism switches the power load between the main breaker and the generator (or other power sources), either manually or automatically. While effective, installing a transfer switch is much more expensive than a generator interlock kit. 

Advantages of a generator interlock kit

While there are other options, such as a transfer switch, there are certain advantages to choosing a generator interlock kit to safely power your home via a portable generator.

Less expensive

Installing a generator interlock kit is less expensive than a transfer switch, but just as safe. 

Easy to operate and install

Since the interlock kit is installed directly on your home’s breaker panel, it does not require a separate panel to operate. However, it does require that you have two or three open spaces on your breaker panel to install.


There’s no need for extension cords to power your appliances or devices during an outage.

Factors to keep in mind when considering a generator interlock kit

Here are a few things to keep in mind before you commit to installing a generator interlock kit.

UL Listing

You want to make sure the kit you install has a UL Listing mark. Some inspectors will not allow the use of kits without this.

It’s permanent

Installing a generator interlock kit will sometimes mean drilling holes into your breaker panel cover. Once the kit is installed, it can’t be removed.

Utility power return alert

Make sure the kit you are considering has a mechanism to alert you to when utility power comes back on so you know when it’s safe to turn your generator off and your main breaker back on. 

Consult a Professional

The electronics professionals at Best Home Services can give you expert guidance on whether a generator interlock kit is right for you. They will guide you through choosing a kit and ensuring it is professionally installed. Give us a call today at (239) 420-8265 and be ready for Mother Nature’s surprises! 

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