Why a Generator Needs a Transfer Switch or Interlock Kit

It’s that time of year again. Fall is here, and winter is just around the corner. Cliche or not, it’s true. Many people are thinking back to this time last year when they were without power for 3 days during the winter storm that left them in the cold, without their heat and electricity to cook family dinners. I don’t mean to start out this blog sounding like a Debbie-downer, but these situations happen to more households than you think, especially in Southeastern PA where snow can pile high, and cause damage to power lines. So what is a person to do? He or she searches for a portable generator to power their home in case of a storm or power failure. But many people don’t realize that it takes more than just plugging in a cord and firing it up. After you have bought your home generator, it’s in desperate need of a transfer switch or an interlock kit so your home’s appliances can be powered safely. Here’s why it’s time to call your local electrician for transfer switch/interlock kit installation.


Why Do I Need a Transfer Switch or an Interlock Kit For My Generator?

Some people that don’t know about transfer switches or interlock kits use extension cords to plug their generator into the appliances that need power; however, this can be a safety hazard for you and your family by having multiple cords coming into the home. Being cautious not to slam or shut windows and doors on the extension cords is something to worry about, since this can cause a short in the cord and cause a fire. Not to mention, you can’t use extension cords to power some of the essentials needed during a winter storm, like your furnace fan that heats your home.


Others might try to bypass the extension cords, and plug their generator into their electrical panel directly without a transfer switch or an interlock kit. If you go to plug in your generator into your electrical panel without one of these, you could destroy your generator, electrical panel, and your home appliances. Not having a transfer switch or an interlock kit could also severely injure the people working on the utility poles, as the electrical currents can back-feed into the power lines.


What is a Generator Transfer Switch?

A generator transfer switch is a device that enables you to connect your generator to your home’s wiring, and is installed near your electrical panel into a dedicated outlet with just one cord. A transfer switch looks like a separate electrical panel, but usually has a limit of 6-8 circuit breakers. The transfer switch allows you to power your most needed circuits that power things like your heating system, refrigerator, sump pump, and many more. You can choose which circuits you would want to power through your transfer switch with the generator, but not all the circuits that are in your main electrical panel.


generator transfer switch

Generator Transfer Switch


How Does a Generator Transfer Switch Work?

A generator transfer switch prevents your utility power and the generator power from working at the same time. When the power goes out and it’s time to use your generator, you would plug it into the transfer switch via an exterior power inlet box (installed by a licensed electrician), turn the generator on, and then turn the switches on from the utility to the generator position for each circuit. Generator transfer switches require a licensed electrician to re-wire your existing circuits of your main electrical panel as well.


exterior inlet

Exterior Power Inlet Box


What is a Generator Interlock Kit?

A generator interlock kit is similar to a transfer switch in that it is a device that allows you to power on your generator through your home’s electrical wiring system. Unlike a transfer switch, an interlock kit allows you to provide power to anything in your home, since it isn’t just limited to 6-8 circuit breakers.


generator interlock kit

Generator Interlock Kit


How Does a Generator Interlock Kit Work?

A generator interlock kit is different from a transfer switch because it isn’t a separate electrical panel. An interlock kit is a system of slide plates that goes directly onto your existing main electrical panel. Just like a transfer switch, an interlock kit makes certain that the utility power and the generator power aren’t on at the same time. When the power goes out, simply turn off the main circuit breaker and the individual circuit breakers on your main electrical panel. Turn on your generator, slide the interlock plate on your main electrical panel, plug in your generator in the power inlet box (installed by a licensed electrician), power on the generator breaker, and lastly, turn on the individual breakers on your main electrical panel that you will need, without overloading your generator.


In Conclusion…

It all comes down to preference and the type of main electrical panel you have, as to which option to choose for powering your generator: either the transfer switch or the interlock kit. The more affordable option would be the interlock kit to power your home generator because it isn’t a separate panel, and it doesn’t require re-wiring of your existing circuits. Some go with the interlock kit because it gives you more options since it can power any area of your home; however, you need to make sure you do not overload your generator with the interlock kit. This is why some homeowners opt for the more expensive option with the transfer switch because they don’t want the hassle of trying to figure out which circuits to choose without overloading the generator. Again, it’s all about preference!


KB Electric LLC’s licensed electricians can help you decide which option is best for you. But remember, you can’t just connect your generator into your electrical panel without a transfer switch or an interlock kit. And who wants to constantly be worrying about tripping over extension cords or creating a short in one? I know I wouldn’t.