How to Wire a Generator to a Breaker Box

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Wire a Generator to a Breaker

The utility power supply of your area can go down, especially at the time of crisis; the power break down is quite often. An emergency backup power is essential in which a portable generator or a standby generator is the best option.

Setting up a generator is not just managing a few power cables from the generator to your home. You have to put much effort to wire a generator to a breaker box. There are some protocols that you can not overlook.

We have formulated a comprehensive guideline bearing all the answers to the queries on how to wire a generator to a breaker box.

The methods and tactics discussed below will assist you in hooking up the generator to the house’s main breaker.

Preliminaries Before the Installation of Generator

Before getting into action, there are a few preparations you need to ensure. Once you have checked and gathered all the essentials, you can begin with installing your generator.

Inspection of the Generator Plug Type and Amperage

When you are preparing to hook up your generator with the breaker box, you must know what you will deal with. It is important to check the plug type and the amperage of your generator.

The generators having a big round power plug will provide 220V of power. Those generators will power both sides of a breaker box. For amperage, you need to search around the pin. The amperage is written somewhere around the plug.

The list below includes some of the most common types. You will also encounter any of them during your generator amperage and plug type inspection.

  • Nema CS6365 (50 amp)
  • Nema L14-30 (30 amp)
  • Nema L14-20 (20 amp)

Assemble All the Essential Tools

Once you are done with the inspection, the next step is to gather all the supplies. The other tools that are also required include:

  • Breaker interlock kit – Check carefully that your breaker interlock kit is compatible with the specific breaker box with which you will wire your generator. Moreover, the kit must be UL rated officially in safety and reliability.
  • 2 Pole double breaker – Make sure that it is also compatible with your breaker box to avoid any inconveniences when you start to wire the generator to the breaker box or ant power outages in the future.
  • Power inlet box – It should match with the amperage of the rest of the gear. It is necessary to ensure the same level of amperage and power outage by every circuit component.
  • Other essentials – The other essential accessories that are required for the installation process are electrical wire (minimum 10 feet of 10 gauge), extension cords (corresponding to the main amperage of the complete circuit), conduit body, and conduit glue (waterproof).

Procedure to Wire a Generator to a Breaker Box

Once you are done gathering all the accessories now, you can begin the process. First, you need to organize a proper passage for the wires from the generator to the breaker box.

breaker board displays many switches

Access Holes

Usually, the exterior walls of the house are provided with access holes. You need to search it, and if it is nowhere, you have to drill one.

It is better to use a hammer drill and drill the hole near the main panel; it will ensure easy management while assembling all the components.

Installation of Conduit

You need to cut the conduit to the right length. The length could vary in your case; just make sure that it reaches properly the inlet box to the access hole. Do not forget to glue it properly while attaching it to the main wall.

Set Up the Generator Inlet Plug

Once the glue has dried properly, open the conduit cover and pull the wires across the tube. Use a screwdriver to fasten each wire with the terminal.

Attach the green or ground wire with the main power inlet box, white wire to the W terminal, black and red wires to the X and Y terminals.

Pull the other ends of the wires into the house and recover the conduit again. To fill the gaps, if there are any, you can use expanding form of silicon.

Preparation of the Existing Breaker Box

First, you need to turn off the main power breaker and all branch circuit breakers. Remove the screws on the front panel onto the breaker box.

Screw in a conduit adapter after removing one of the knockout panel parts. Make sure to it fit tightly. Now stretch the wires carefully through the conduit and into the breaker box.

In case you need more space, you can move one or two breakers down the main panel a bit. If the wires are not loose enough for this, you can use a short piece of insulated wire as a small extension cord.

Installation of Wires and Generator Power Breaker

After freeing up the space, you can easily install the new circuit breaker.

Attach the red wire to one terminal, black wire to the other terminal, white wire to the common bond rail in the circuit breaker box, and the green wire to the matching ground rail.

Then use a retaining bracket to tighten the breaker. Use the retaining bolt to attach the retaining bracket. Hence, the installation will successfully end here.

Frequently Asked Questions

Can I connect a generator to the house without a manual generator transfer switch?

You can hook up a generator to your house without a manual transfer switch. You have to wire it directly to the main electric panel. To connect the generator directly to the main electrical panel, you must use a subpanel.

Can you connect a generator to your house without an automatic transfer switches?

There are numerous reasons why having one installed in your home is highly recommended but you can connect the generator to the panel without an automatic transfer switch. But, you should have some sort of manual transfer switch in this case.

What causes a generator breaker to trip?

A generator might trip due to either the circuit breaker disrupting the supply. Another reason might be with the Ground Fault Circuit Interrupter (GFCI) receptacles. All generators have circuit breakers and fuses. These components trip or disconnect the electric supply whenever there is a potential threat to the connected devices.


After finishing the installation, you need to check that all the things are assembled adequately and working properly. Once you are assured that the generator is connected correctly, you can power everything up.