Are Generator Interlock Kits Legal?

are generator interlock kits legal in florida, Michigan, California, New York, Virginia, Ohio, Texas, New Jersey, nc

Being prepared for a power outage is the best thing you can do for your house. The experience of being without electricity is very inconvenient if you’re not used to it; not to mention the risk of damage to equipment and electrical supplies. When the power goes out after a storm, there is no telling when it would be coming back. If you live in an area where maintenance takes time, you may be without power for even days or weeks at a time depending on the damage. 

This is why it pays to be prepared. Many people have chosen to keep generators in their houses to be prepared for untimely power outages. With the discussion around generators, the discussion around interlock kits has also become a hot topic. Many people question if interlock kits are legal to use, and if yes, then why is there such a big concern about their legal status. 

We’re here to answer these questions today. Read on to find out!

Generator Interlock Kits – What do they do?

Generator interlock kits are devices designed to ensure that during a power outage, the house is powered safely by the generator. Interlock kits detect when the power goes out and automatically shift the house’s electricity supply system to the generator. 

How do interlock kits work?

Interlock kits work by adding an external interlock on the breaker panel. This allows one of two things to happen at a time: either the main breaker is turned on, or a designated load breaker is turned on. Since both cannot be turned on at the same time and one has to be on, the interlock kit shifts the breaker panel on to the generator as soon as the electricity supply is cut off. Pretty simple, right?

When the power supply is on, it comes through the main breaker. The main breaker accepts the supply from the external mains and leads it into the panel. The interlock has the back feed breaker for the other line turned off, so the power does not go back into the generator. If the back feed breaker is not turned off, it may damage the generator. 

When the power goes out, the back breaker is turned on. Power is allowed to flow from the generator into the panel. Since the main breaker is off at this point, electricity does not flow back to the external main lines. Back feeding the external mains is strictly prohibited because it can overload the generator and cause damage and may even electrocute line workers or start fires. 

Why are they unacceptable in some areas?

If you have installed an interlock kit in your home or are planning to do so, there is a chance that depending on the area you are living in, you may be asked to remove it on the next visit of your electrical regulatory authority representative. This is because interlock kits are not allowed in many places. Why? Because of the danger of back feeding. Back feeding can be very dangerous and may cause serious harm to line workers or the electrical wiring system. 

Interlock kits are also considered dangerous because of what may happen if a person manually takes the panel off and turns the main line on while the generator is connected. This may cause back feeding and also damage the generator because of overloading. While interlock kits are designed in such a way that they are turned off as soon as the panel is taken off, there is still a danger of misuse and harm to the main lines. 

While most electrical authorities do not allow interlock kits, especially in residential areas, there is no real consensus over how safe they are. Many people think that interlock kits are safe, and most models are designed specifically to prevent any possibility of misuse. However, others still have doubts. 

Are generator interlock kits legal to use?

Now comes the real question. Are they legal?

Nova ScotiaYES
Florida  YES
Oregon  YES
Michigan  YES
new york  YES
Connecticut  YES
New Jersey  YES
Kentucky  YES
Louisiana  YES
Wisconsin  YES
Maine  YES

Generator interlock kits are legal in most parts of the US if they are approved by the UL under their standard UL 67. The interlock kits you install should have the UL listing otherwise they may be objected upon by electrical inspectors. They should also be installed by professionals trained to abide strictly by the protocol of the National Electrical Code and National Fire Protection Code, and the person getting them installed should receive complete guidance on their use and the penalties of misuse. 

While you will be hard-pressed to find a region in the US that prohibits the use of interlock kits, make sure you read the local codes carefully. Some building, fire, and electric codes place restrictions on the use of interlocks.

In other words, they specify the circumstances in which you can use them and the precautions you must take beforehand. Try to remain abreast of changes in the local code. Most US states permit the use of interlocks today. But that may change in the next few weeks, months, or years once new data comes to the surface.

You don’t want to attract hefty fines because you made decisions based on outdated electric codes.

The legality of generator interlock kits also depends strongly on the company manufacturing these kits. It should be clearly mentioned on the company’s page, whomever you are planning to purchase from if their kits are legal in your country or not. If they have not mentioned any such thing, there is a chance they’re hiding something, and you should do a little digging for yourself!

What is the best alternative to generator interlock kits?

An alternative to generator interlock kits, whose legal side you won’t have to worry about, are transfer switches. They perform the same function but take up more space and are more expensive than interlock kits. However, their safety and lack of legal concerns allow them to be a superior option.

If you don’t have enough space by your breaker panel or want to save on the extra costs, be sure to do thorough research about any potential safety hazards of the interlock kit you are purchasing. If misuse of your kit does not cause any harm to anyone else, it will probably still damage your generator and render it useless. Also, look into the laws in your particular area to make sure you aren’t faced with any unwelcome surprises on your next visit by the electrical inspector.


While interlock kits approved by the UL standards and listed in UL listings are legal in most parts of the US, they are not allowed in several other countries. This is why you need to make sure you are aware of the laws of your particular area to avoid problems. 

Related post:

Leave a Reply

Your email address will not be published. Required fields are marked *

Recent Posts