Hook Up Generator to Breaker Box

A generator comes in handy in lots of ways during blackouts. However, you have to hook it up to your house to enjoy the benefits. What you need to know is, wiring a generator might seem like a tedious task. But guess what? It’s not! It’s quite a straightforward process when done right. What you need is to understand the wiring concept and the hooking up.

Wiring Basics You Need to Understand

Let’s assume you have a 240-volt circuit in your home; you will have a couple of wires working together as live 240-volts currying 240 volts. There is also a green or copper-colored wires known as the ground. With a 240-volt system, there is no neutral wire you can use.

You might want to use a 240-volt circuit for both 240-volt and 120-volt applications. If your generator comes with a 240-volt connection, the hookup gets easier. But it would be best if you did this with 240-volt capabilities.

What do you need?

Handling electrical task requires you to have the right tools to keep clean and perfect. Here are the few materials you need to connect your generator to the breaker box.


A Voltmeter

A Stripper Tool

Long Eight-by-Three Cable

A Pair of Electrical Safety Gloves

Electrical tape (black preferably)

A Screwdriver (with flathead preferred)

A double pole breaker with 40-amp power

Steps on how to hook up generator to breaker box

To hook up your generator to the breaker box might surprise you with its simplicity. But don’t take me wrong; a misstep can lead to a hazardous situation that can lead to electrocution and damage to your appliances and electronics. That’s why you need to take it seriously and follow along.

Step 1: Get Yourself Ready

Before you engage in anything, get yourself ready. Wear the right electrical gloves, apron, if necessary and protective glasses to protect your eyes during all the drilling.

Step 2: Turn off the main

The next step on how to hook up a generator to a breaker box is to shut your house’s main power source. Once you’re done, use a voltmeter to make sure the line is not active and if the electricity termination into your breaker box is done right. If any voltage is flowing, never start till it stops.

Step 3: Stripping the Wires

Now take the 8×3 cable and use it for this step. You have to strip the wire’s end to expose the wire’s right side, about half an inch. The stripper tool will help in making a cleaner cut safely.

Step 4: Drilling the holes

It’s time now to drill a hole for the inlet box installation. Before you do the drilling, find a convenient place for the generator, somewhere far from the windows and the doors and a few feet from the house. It would be best if you also considered the length of your generator extension cord while you choose the spot.

Once you’re done, it’s time to drill. Pick your generator inlet box and use something hard, a nail, or a stick to draw on the wall the size of hole you need using the hole inside the inlet box. Once done, you can use the ideal drilling machine to create the hole and run through the cables.

Step 5: Wiring

In this step, you need to make sure the ground wire is running through similar bars. It needs to run till the last point of the 240-volt receptacle inside your breaker box. Once you’ve inserted the ground wire, screw it tightly. Once that is done, it’s time to run the 8×3 through the walls till you reach the breaker box.

Step 6: Screwing Wires

Pick the two black wires and crew them to the main backup circuit breaker gradually. There are two screws inside the circuit breaker to help hold these two wires separately and safely. Pick the wires individually and insert them fully into the terminals. Tighten them with the screws securely and ensure they do not go out.

Step 7: Fixing the Breaker to Service Panel

You now have to fix the breaker into the service panel. You should find a free spot to insert it somewhere convenient. Inserting the breaker isn’t anything complicated; you need to snap it in, and you’re done. Pick the breaker, place it right and snap it in and use the back and forth rocking motion. That way, it gets easier to put the tabbed breaker end in the housing first.

And to finish the installation, you need to snap-rest the breaker over the hot bus bar. If you’re using a double pole breaker, make sure it fits properly. The double pole breaker is ideal for 240-volt generator hookup and does come with two 120-volt hot wires that sum the voltage to 240 volts.

Step 8: Installing an interlock device

Hooking up a generator to the breaker box without a transfer switch or interlock device is illegal. That’s why you need to install one in your service panel.

Why go for an interlock device? If you’re hooking up a portable generator, an interlock device is the most convenient device. It’s cheaper than a transfer switch, easy to install and use. How does it work? It works by keeping one power line shut while the other operates. If your main power line is on, the interlock device will keep the backup generator breaker off and vice versa.

How do you install it? Installing the interlock device is easy. All you need is to drill small holes for the screws on the breaker box inner cover near the main power breaker. Position it in a way that, when it’s slide up or down, it prevents one breaker (main power or generator power) from going on. Screw it down using the installation manual, and you’re good to go.

Step 9: Installing the inlet box

Once everything is connected to the breaker box, and the wires have reached the outside where you want to plug in the generator, you can now install the generator inlet box. Remember, the breaker needs to match your generator rating in amps. Fix in the weather cover and make it tight. Follow by screwing in the wires to the box terminals using the labeled directions. Next, snap the inlet to the weather cover and use silicon sealant to make it watertight.

Step 10: Hooking up the generator.

Now it’s time to hook up the generator and test if the power is getting to the breaker box. Go back to the breaker box and make sure the interlock is on the generator backup breaker, and it’s on. Also, if you’ve got lots of appliances in the house and you don’t want some to receive the backup power, here is the point to specify that. Shutdown the unnecessary circuits and leave the others on.

Start your generator and allow it to stabilize. Use an extension cord ideal for your generator size and capacity, hook it up one end in the inlet box, and the other on the generator outlet. Test the lights inside the house; if they are lighting, bingo, you did it.


As you can see, it’s relatively easy to hook up generator to a breaker box. Everything is straightforward. All you need is to follow the simple steps, use the right tools, and keep the work clean. Secure everything by tightening the screws and leave all the wires covered. As I mentioned, position the generator right to prevent noise pollution for the residents and CO poisoning.


About the author

Sharif Miah

I am Sharif, 22, a student, currently doing the BBA program. Besides, I am an online Blogger.

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