Skip to Content

Are Generator Interlock Kits Legal? [Briefly Explained]

During a power outage, generator interlock kits allow houses to be powered by a portable generator. There are some legality issues with using generator interlock kits. That’s why you can definitely get confused. 

Are generator interlock kits legal?

Most areas of the United States allow generator interlock kits. Only if the UL has licensed them under UL 67. That’s why you must ensure that the interlock kits are UL listed and accepted by electrical inspectors. These kits must be installed in accordance with the National Electrical Code and the National Fire Protection Code. 

You must still be puzzled about the inquiries. You will find all of the answers to your inquiries here.

Find out more about this in our article!

How Do Generators Interlock Kits Function?

Adding an external interlock to the circuit breaker panel is how interlock kits function. In this way, the main breaker can be activated. Or a specific load breaker can be activated in parallel. For extra safety, you can use a 3000 watt generator.

It is necessary to install an interlock kit for reasons of safety. This way when electricity is lost, a generator will take over the breaker panel.

The main breaker is where the electricity enters the building. Using the main breaker, the panel receives power from the external mains and distributes it. As a result, power from another interlocked line cannot return to the generator. 

Generators are at risk of overheating when the back feed breaker is not shut down. If there is a power outage, the backbreaker is activated to prevent further damage. The generator is connected to the panel, allowing power to flow.

Electricity does not return to the exterior main lines. Because the main circuit breaker has been shut off.

It is a crime to feed current back into the exterior mains. Due to the risk of causing the generator to malfunction. It can cause damage and possibly electrocution of line workers or fires.

Is It Allowed to Use Generator Interlock Kits?

Generator interlock kits can be used in most regions of America. Only if they meet the UL’s certification.

Electrical inspectors may object to the interlock kits you install. This will happen if they don’t have the UL listing. 

These devices must be installed in accordance with the National Electrical Code and the National Fire Protection Code. The person installing them should receive complete instruction on operating them. They should also know the penalty for misuse.

Generator interlock kits’ legality is inextricably linked to the firm that makes them. On the company’s web page, one thing should be explicitly stated. What you need to know is whether or not their kits are legal in your own area. 

They may be hiding anything if they have not disclosed it. So, you should do some investigating for yourself!

Why Are Generator Interlocks Deemed Unacceptable in Certain Areas?

You may be requested to take out your generator interlock kit at times as well. And this will be done by your local electrical regulatory authority agent.

The reason for this is that interlock kits are banned in many places. Because of the possibility of problems from back-feeding. Workers on the line or the electrical wiring system could be seriously harmed by back feeding.

It is also dangerous to manually remove the interlock panel. It is also hazardous to switch on the mainline when a generator is connected. 

In the worst-case scenario, the generator could shut down. Back feeding and overloading of the generator are also possible consequences of this. 

Interlock kits are supposed to be cut off immediately when the panel is removed. But main lines can still be damaged. 

It’s unclear how safe interlock kits are, especially in residential areas. That’s why most electrical authorities don’t allow them. 

But still, interlock kits are widely believed to be risk-free. In most cases, they’re designed to prevent unwanted access. Furthermore, you can avoid tripping circuit breakers with it.

Should You Use a Generator Interlock Kit?

Using an interlock kit has a lot to commend. You’ll surely see a positive change by using it. For example, here are some pros of using it:

Makes Your Work Easy

Extending cords is a hassle when connecting your generator directly to appliances. Moving big appliances like a fridge to plug them into an extension cord might be difficult. But not with an interlock system. 

No Need For Extra Breaker Panel

No additional breaker panel is needed for the kit. You can find it in your home’s breaker panel. As a result, there will be significant savings in time and money.

Consumes Less Power But Provides More

It consumes the needed power by the appliances plugged into your portable generator. This is generally a lot less than it can do. With interlock kits, you can use the generator’s full load capability and power more of your home.

Moreover, interlock kits cost significantly less than transfer switches. It’s also pretty cheap to install interlock kits.

If you are interested, you can go through suggestions regarding the kits below-

Product 1
Product 2

Alternative to Generator Interlock Kits 

You might still be worried about whether to use interlock kits or not. In that case, I have a great alternative for you. You won’t have my headache regarding the legal issue of this item.

The alternative to the generator interlock kits is the transfer switches. These perform in a similar way as the interlock kits. But there’s a downside. They are expensive and require more space. 

Still, these problems are overshadowed easily because of their safety. And as the switches are safe, they are legal in almost every region of America.

A transfer switch is needed if the generator you have is above 5000 watts. You won’t have to worry about anything after putting the switch. Your safety will be guaranteed. 

The switch is best for both portable and standby generators. You can easily purchase the switches for your generators and get them installed. 

There are two varieties: automated and manual. The manual switch is used for portable generators mainly. But automated ones are mostly used in industrial factories. 

That’s all for both generator interlock kit and transfer switches!


Question: How can I get my interlock kit to be legal?

Answer: Adhere to the rules that demand that a single device shield the interlock kit from overcurrents. Make sure the backup system can manage a full load of your backup generator.

Question: Why use an interlock kit rather than a transfer switch?

Answer: While a transfer switch is a more long-term and reliable choice, an interlock kit is much simpler to install. Putting it in will be a breeze. Interlock kits are typically less expensive than a transfer switch. Because they don’t require installations.

Question: How much does it cost to get a generator interlock kit installed?

Answer: You should expect to pay between $50 and $150 for an interlock system. The homeowner can install these. But a licensed electrician can help ensure that they are done correctly and comply with local building codes.

Bottom Line

You may now have no questions about whether general interlock kits are legal or not. For the simple reason that this article contains all the pertinent legal information.

If you’re still unsure about the legalities, you can consult with experts. This will help you until then.

Best of luck!