How To Wire A Transfer Switch To Your Home (Step By Step)

Installing a transfer switch to your home allows you to easily and safely switch incoming power from your main electrical panel to a portable generator in the event of a black out/power outage.

Transfer switches come in two configurations, manual and automatic, and both have their pros and cons.

Once you have your switch, you can decide to have it professional installed or tackle the simple process yourself. In this article, Iwill walk you through the process of wiring a transfer switch to your home and guide you to my top picks on the part you will need.

Parts needed

In order to get your transfer switch properly installed, you are going to need some parts.

You can buy a comprehensive kit that includes everything you may need, or you can piece together the parts you need.

We will look at all of your options for parts to save you the time researching on your own.

Portable Generator

Obviously you are going to need a decent sized portable generator. 

Lucky for you, I have broken down the top portable generators available in an easy to use buyers guide. You can check that out here – https://generatorgrid.com/

Individual Transfer Switch

electrical transfer switch
Image credits: Interlock Kits

If you are wanting to order just a switch, you can order a manual or automatic transfer switch individually. Here are a couple of my suggestions:

  • Maximum Running Generator Watts: 7,500
  • cUL1008 Listed
  • 5 Year Product Warranty
  • Maximum Running Generator Watts: 7,500
  • Outdoor capable
  • 1 Year Warranty

Power Inlet Box

power inlet box on a brick wall

The power inlet box mounts on the outside of your house on the other side of the wall of your indoor transfer switch.

It allows you to easily plug in a power cord to connect to your generator. Here are a couple of inlet boxes I found to be great picks.

    • 30 Amp
    • 125/250 Volts
    • Up to 7,500 Running Watts
    • 50 Amp
    • 125/250 Volts
    • Up to 12,500 Running Watts

Generator power cord

To connect the generator to the transfer switch, you are going to need a power cord. A 20 foot cord is standard and is usually plenty to make the connection.

    • 30 Amp
    • 20 Foot
    • Up to 7,500 Running Watts
    • 50 Amp
    • 20 Foot
    • Up to 12,500 Running Watts

Transfer Switch Installation process

Wiring a transfer switch to your home can be a daunting process, but with a little bit of electrical knowledge and an attention to detail of the process, you can have the job done in a few hours.

If you do not feel comfortable working with your home’s main electrical panel, please seek professional help.

Since you will be working with your home’s main electrical supply, we highly recommend reviewing your local and state laws and code requirements before tackling this install to prevent any broken laws or code violations.

Have a look at the video above from This Old House

  1. First you will want to figure out where you would like the switch to be mounted. You will want this near your panel box for easy installation.
  2. Once you figure out a safe place for your switch, away from an obstructions, you can now securely mount your switch to the wall.
  3. Switch off the main power to your house at the main electrical panel. You can test your appliances to double check that the power is off.
  4. Locate the wires that are coming from the transfer switch and connect them to the circuits in your panel box that you wish to control.
  5. Drill a 1 ½” hole through your house wall (from the outside) near the switch. This will be used to feel wires through from the switch to the electrical recepticle.
  6. If your switch came with an outdoor electrical box, mount this above the hole on the exterior wall.
  7. Now, connect the electrical cable from the transfer switch to the electrical box, snaking it through the drilled hole.
  8. Connect the electrical receptacle to the electrical cable in the outdoor box and screw/mount it to the box.
  9. Before testing your work, make sure that your portable generator is in good working order
  10. Now to test your work, with your main power still off, use the generator power cord to connect the generator to the outdoor electrical receptacle.
  11. Start your generator and flip the transfer switch (from line to generator). Your connected appliances should now have power.
  12. Once everything is confirmed to be working properly, turn the transfer switch from generator to line. You can now turn your main power back on.
  13. It is a good idea to seal the hole that you have drilled to prevent bugs, moisture, and dirt from getting in your home.

In Conclusion

Wrapping things up, the install is not as daunting as most may think.

The most important takeaways are to ensure you have a generator capable of powering the appliances you need, ensuring you have all of the correct parts that you need, reviewing code regulations, installing the parts correctly, and checking for proper function when finished.

Installing a transfer switch is not a common task and I want to hear from those who have installed them.

What was the hardest part of your install? Would you install one again?

2 thoughts on “How To Wire A Transfer Switch To Your Home (Step By Step)”

  1. I live inside the city limits. Can I legally install a 30 amp Inlet box that is hardwired to a circuit breaker in my main home circuit panel without having to use an electrician.?

  2. Tim,
    That will depend a lot on your municipality. Here in Kansas City, Missouri, a home owner can perform electrical repairs and upgrades without the help of an electrician as long as they’re going to do the work themselves and obtain the proper building permits.

    Any other municipality may well have different rules. For safety’s sake, many will require the work to be done by a licensed professional. If the city you live in has a local codes administration, talk to them about the specifics there. If the city has no specific codes or requirements in place for electrical upgrades of this sort, check with the county.

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