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How to Connect Generator to House without Transfer Switch

Written by Edwin Jones / Fact checked by Andrew Wright

how to connect generator to house without transfer switch

Do you frequently experience sudden electricity loss in your place? Do you want to know how to connect generator to house without transfer switch?

If you frequently experience a sudden loss of electricity at your place, you probably want to use generators as your backup electricity. And using an extension to hook up generator to house without transfer switch is easy, but it is a bit messy, right?

To make it clean and more accessible, I highly suggest installing a generator plug for house, which you will learn in this article.


Tools You Need


  • Double outlet receptacle kit for a clean electrical connection
  • Three prong round plug and wire for connecting the power inlet box to portable generator
  • Power consumption watt tester for reading the wattage produced by your portable generator
  • Extension cord for connecting the power inlet inside to the generator
  • Hand drill for making a hole in the wall
  • Oscillating tools to cut out drywall
  • Philip screw for fixing the receptacle
  • Safety gear for additional safety since you are working with power tools
  • Metal waterproof box for keeping line safe from any possible damage
  • Sealant for making a solid waterproof installation
  • Generator set for backup electricity

You can use an old extension, but you must ensure that the line and end plugs are not damaged.

The perfect length for the line to connect your generator is at least 25 feet. You can use as much as you need to connect the generator, but it also requires a sizable waterproof storage box.

I use a generator power with 3500 watts and 30 amp breakers with 120 volts electrical supply for this application. You wouldn’t need anything more powerful as this is a power outage backup only. You may want to use a more powerful generator, but you should upgrade the electrical wires you need to connect it.

Furthermore, it is ideal to use an automatic transfer switch for connecting generator to house, especially if you have more extensive and higher voltage generators.

Step-by-Step Guide on How to Use a Generator Without Needing Any Transfer Switch


Step 1: Create a Place for the Outlet Utility Box


Create a place for the generator outlet in your preferred location. To do this, create a rectangular hole that fits your outlet on the wall using your oscillating tool for wood and drywall. If you have a concrete cement wall, you can also use your drill.

Step 2: Drill a Hole for Running Your Generator Cables to the Outlet


Using your drill, make a hole to run your wires from the outside of your house. Ensure that it is bigger than the expected diameter of your wires. This way, you can prevent damaging the electrical wires when installing them inside your outlet kit.

Step 3: Install the Waterproof Box Outside Your Wall


On the outside wall, install your waterproof box. This box is to protect your end plug from any possible damage. You can use any safety box like this Sigma Electric Box for covering the end plug. However, you may need to find a larger safety box that will fit your wires.

Step 4: Connect the Wire Into the Outlet


To connect the wires to your outlet kit, insert the other end of the wires with a plug outside your house. After inserting the line, you can now assemble the outlet kit inside.

When you assemble the outlet and the wire, you can seal the exterior and interior hole with a sealant. You need this for waterproofing your installation.

Step 5: Connect Generator to Outlet and Test it

To test this plug type connection, turn on your generator power, hook the inlet plug, and connect the extension into the generator inlet plug. Connect your power consumption tester and attach some appliances with a power rating that’s compatible with your generator to read how many watts your generator produces.

You can watch this video by GetMyTips to connect a generator to a house. It gives you a visual of how this step-by-step guide can be done safely.

How Many Appliances and Devices Can I Use with a 3000 Watts Generator

The answer depends on how many watts your appliances have or how many devices you have in your house. You can even use several lights with lower wattage and some electric devices like a phone charger and laptop computer at the same time.

It means you can run multiple devices and lights as long as it does not exceed the generator’s maximum capacity.

However, if you need to run power-hungry appliances like a portable electric stove, you may need to run it individually. This is to prevent overloads that may cause damage to your generator’s circuit. It’s also good practice to do essential reviews of your house appliances’ power draw before using them on your backup power supply.

Note: Miscalculation of wattage may cause overloads which can damage your generator circuit. So instead of aiming for the maximum power rating of 3000 watts, you should approximately target 2500 to 2800 watts only. This will prevent damage to your generator and extend its lifespan.

Will a 15-Kilowatt Generator Run a House


Most average household appliances use 3000 to 6500 watts of circuit power. Therefore, if you have a 15-kW generator, you can probably run all of your house appliances and lights with it. Furthermore, it usually supports both 120-volt and 240-volt electrical power output, letting you run both low-power and high-power machines.

In a simple explanation, 1 kW is equal to 1000 watts of power rating. Hence, a 15-kW generator set has a rating of 15,000 watts. However, if you have more powerful appliances that you use all at once, even a 15-kW generator might not be enough. You should compute your household requirement first before running them all on your generator.

Furthermore, using manual transfer switches or a generator interlock or an automatic transfer switch is essential in a 15-kW backup electrical supply. This way, you can easily switch to the electrical main power supply when power returns.

Because if you have your backup electricity running at the same time as your main power supply, you could damage your generator.


This method of connecting a generator to a house without an installed transfer switch is convenient, especially if you only need a small electrical generator.

For this application, you are free to use any safety box, especially if you want to use extension cords.

So, what do you think of this step-by-step guide on how to connect generator to house without transfer switch? Is it worth sharing this idea with your neighbor? Share your thoughts in the comment section below.

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